Migrate to AndroidX from the Android Support Library. https://redmine.stoutner.com...

[PrivacyBrowserAndroid.git] / app / src / main / java / com / stoutner / privacybrowser / activities / MainWebViewActivity.java

/*
 * Copyright © 2015-2019 Soren Stoutner <soren@stoutner.com>.
 *
 * Download cookie code contributed 2017 Hendrik Knackstedt.  Copyright assigned to Soren Stoutner <soren@stoutner.com>.
 *
 * This file is part of Privacy Browser <https://www.stoutner.com/privacy-browser>.
 *
 * Privacy Browser is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Privacy Browser is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Privacy Browser.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.stoutner.privacybrowser.activities;

import android.Manifest;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.DownloadManager;
import android.app.SearchManager;
import android.content.ActivityNotFoundException;
import android.content.BroadcastReceiver;
import android.content.ClipData;
import android.content.ClipboardManager;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.SharedPreferences;
import android.content.pm.PackageManager;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Typeface;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.net.Uri;
import android.net.http.SslCertificate;
import android.net.http.SslError;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.preference.PreferenceManager;
import android.print.PrintDocumentAdapter;
import android.print.PrintManager;
import android.text.Editable;
import android.text.Spanned;
import android.text.TextWatcher;
import android.text.style.ForegroundColorSpan;
import android.util.Patterns;
import android.view.ContextMenu;
import android.view.GestureDetector;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.view.inputmethod.InputMethodManager;
import android.webkit.CookieManager;
import android.webkit.HttpAuthHandler;
import android.webkit.SslErrorHandler;
import android.webkit.ValueCallback;
import android.webkit.WebBackForwardList;
import android.webkit.WebChromeClient;
import android.webkit.WebResourceResponse;
import android.webkit.WebSettings;
import android.webkit.WebStorage;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.webkit.WebViewDatabase;
import android.widget.ArrayAdapter;
import android.widget.CursorAdapter;
import android.widget.EditText;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.RadioButton;
import android.widget.RelativeLayout;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.ActionBarDrawerToggle;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.coordinatorlayout.widget.CoordinatorLayout;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
// `ShortcutInfoCompat`, `ShortcutManagerCompat`, and `IconCompat` can be switched to the non-compat versions once API >= 26.
import androidx.core.content.pm.ShortcutInfoCompat;
import androidx.core.content.pm.ShortcutManagerCompat;
import androidx.core.graphics.drawable.IconCompat;
import androidx.core.view.GravityCompat;
import androidx.drawerlayout.widget.DrawerLayout;
import androidx.fragment.app.DialogFragment;
import androidx.fragment.app.FragmentManager;
import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;

import com.google.android.material.floatingactionbutton.FloatingActionButton;
import com.google.android.material.navigation.NavigationView;
import com.google.android.material.snackbar.Snackbar;

import com.stoutner.privacybrowser.BuildConfig;
import com.stoutner.privacybrowser.R;
import com.stoutner.privacybrowser.dialogs.AdConsentDialog;
import com.stoutner.privacybrowser.dialogs.CreateBookmarkDialog;
import com.stoutner.privacybrowser.dialogs.CreateBookmarkFolderDialog;
import com.stoutner.privacybrowser.dialogs.CreateHomeScreenShortcutDialog;
import com.stoutner.privacybrowser.dialogs.DownloadImageDialog;
import com.stoutner.privacybrowser.dialogs.DownloadLocationPermissionDialog;
import com.stoutner.privacybrowser.dialogs.EditBookmarkDialog;
import com.stoutner.privacybrowser.dialogs.EditBookmarkFolderDialog;
import com.stoutner.privacybrowser.dialogs.HttpAuthenticationDialog;
import com.stoutner.privacybrowser.dialogs.PinnedMismatchDialog;
import com.stoutner.privacybrowser.dialogs.UrlHistoryDialog;
import com.stoutner.privacybrowser.dialogs.ViewSslCertificateDialog;
import com.stoutner.privacybrowser.helpers.AdHelper;
import com.stoutner.privacybrowser.helpers.BlockListHelper;
import com.stoutner.privacybrowser.helpers.BookmarksDatabaseHelper;
import com.stoutner.privacybrowser.helpers.DomainsDatabaseHelper;
import com.stoutner.privacybrowser.helpers.OrbotProxyHelper;
import com.stoutner.privacybrowser.dialogs.DownloadFileDialog;
import com.stoutner.privacybrowser.dialogs.SslCertificateErrorDialog;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.lang.ref.WeakReference;
import java.net.InetAddress;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

// AppCompatActivity from android.support.v7.app.AppCompatActivity must be used to have access to the SupportActionBar until the minimum API is >= 21.
public class MainWebViewActivity extends AppCompatActivity implements CreateBookmarkDialog.CreateBookmarkListener, CreateBookmarkFolderDialog.CreateBookmarkFolderListener,
        CreateHomeScreenShortcutDialog.CreateHomeScreenShortcutListener, DownloadFileDialog.DownloadFileListener, DownloadImageDialog.DownloadImageListener,
        DownloadLocationPermissionDialog.DownloadLocationPermissionDialogListener, EditBookmarkDialog.EditBookmarkListener, EditBookmarkFolderDialog.EditBookmarkFolderListener,
        HttpAuthenticationDialog.HttpAuthenticationListener, NavigationView.OnNavigationItemSelectedListener, PinnedMismatchDialog.PinnedMismatchListener,
        SslCertificateErrorDialog.SslCertificateErrorListener, UrlHistoryDialog.UrlHistoryListener {

    // `darkTheme` is public static so it can be accessed from everywhere.
    public static boolean darkTheme;

    // `allowScreenshots` is public static so it can be accessed from everywhere.  It is also used in `onCreate()`.
    public static boolean allowScreenshots;

    // `favoriteIconBitmap` is public static so it can be accessed from `CreateHomeScreenShortcutDialog`, `BookmarksActivity`, `BookmarksDatabaseViewActivity`, `CreateBookmarkDialog`,
    // `CreateBookmarkFolderDialog`, `EditBookmarkDialog`, `EditBookmarkFolderDialog`, `EditBookmarkDatabaseViewDialog`, and `ViewSslCertificateDialog`.  It is also used in `onCreate()`,
    // `onCreateBookmark()`, `onCreateBookmarkFolder()`, `onCreateHomeScreenShortcutCreate()`, `onSaveEditBookmark()`, `onSaveEditBookmarkFolder()`, and `applyDomainSettings()`.
    public static Bitmap favoriteIconBitmap;

    // `favoriteIconDefaultBitmap` public static so it can be accessed from `PinnedMismatchDialog`.  It is also used in `onCreate()` and `applyDomainSettings`.
    public static Bitmap favoriteIconDefaultBitmap;

    // `formattedUrlString` is public static so it can be accessed from `AddDomainDialog`, `BookmarksActivity`, `DomainSettingsFragment`, `CreateBookmarkDialog`, and `PinnedMismatchDialog`.
    // It is also used in `onCreate()`, `onOptionsItemSelected()`, `onNavigationItemSelected()`, `onCreateHomeScreenShortcutCreate()`, `loadUrlFromTextBox()`, and `applyProxyThroughOrbot()`.
    public static String formattedUrlString;

    // `sslCertificate` is public static so it can be accessed from `DomainsActivity`, `DomainsListFragment`, `DomainSettingsFragment`, `PinnedMismatchDialog`, and `ViewSslCertificateDialog`.
    // It is also used in `onCreate()` and `checkPinnedMismatch()`.
    public static SslCertificate sslCertificate;

    // `currentHostIpAddresses` is public static so it can be accessed from `DomainSettingsFragment` and `ViewSslCertificateDialog`.
    // It is also used in `onCreate()` and `GetHostIpAddresses()`.
    public static String currentHostIpAddresses;

    // `orbotStatus` is public static so it can be accessed from `OrbotProxyHelper`.  It is also used in `onCreate()`, `onResume()`, and `applyProxyThroughOrbot()`.
    public static String orbotStatus;

    // `webViewTitle` is public static so it can be accessed from `CreateBookmarkDialog` and `CreateHomeScreenShortcutDialog`.  It is also used in `onCreate()`.
    public static String webViewTitle;

    // `appliedUserAgentString` is public static so it can be accessed from `ViewSourceActivity`.  It is also used in `applyDomainSettings()`.
    public static String appliedUserAgentString;

    // `reloadOnRestart` is public static so it can be accessed from `SettingsFragment`.  It is also used in `onRestart()`
    public static boolean reloadOnRestart;

    // `reloadUrlOnRestart` is public static so it can be accessed from `SettingsFragment` and `BookmarksActivity`.  It is also used in `onRestart()`.
    public static boolean loadUrlOnRestart;

    // `restartFromBookmarksActivity` is public static so it can be accessed from `BookmarksActivity`.  It is also used in `onRestart()`.
    public static boolean restartFromBookmarksActivity;

    // The block list versions are public static so they can be accessed from `AboutTabFragment`.  They are also used in `onCreate()`.
    public static String easyListVersion;
    public static String easyPrivacyVersion;
    public static String fanboysAnnoyanceVersion;
    public static String fanboysSocialVersion;
    public static String ultraPrivacyVersion;

    // The request items are public static so they can be accessed by `BlockListHelper`, `RequestsArrayAdapter`, and `ViewRequestsDialog`.  They are also used in `onCreate()` and `onPrepareOptionsMenu()`.
    public static List<String[]> resourceRequests;
    public static String[] whiteListResultStringArray;
    private int blockedRequests;
    private int easyListBlockedRequests;
    private int easyPrivacyBlockedRequests;
    private int fanboysAnnoyanceListBlockedRequests;
    private int fanboysSocialBlockingListBlockedRequests;
    private int ultraPrivacyBlockedRequests;
    private int thirdPartyBlockedRequests;

    public final static int REQUEST_DISPOSITION = 0;
    public final static int REQUEST_URL = 1;
    public final static int REQUEST_BLOCKLIST = 2;
    public final static int REQUEST_SUBLIST = 3;
    public final static int REQUEST_BLOCKLIST_ENTRIES = 4;
    public final static int REQUEST_BLOCKLIST_ORIGINAL_ENTRY = 5;

    public final static int REQUEST_DEFAULT = 0;
    public final static int REQUEST_ALLOWED = 1;
    public final static int REQUEST_THIRD_PARTY = 2;
    public final static int REQUEST_BLOCKED = 3;

    public final static int MAIN_WHITELIST = 1;
    public final static int FINAL_WHITELIST = 2;
    public final static int DOMAIN_WHITELIST = 3;
    public final static int DOMAIN_INITIAL_WHITELIST = 4;
    public final static int DOMAIN_FINAL_WHITELIST = 5;
    public final static int THIRD_PARTY_WHITELIST = 6;
    public final static int THIRD_PARTY_DOMAIN_WHITELIST = 7;
    public final static int THIRD_PARTY_DOMAIN_INITIAL_WHITELIST = 8;

    public final static int MAIN_BLACKLIST = 9;
    public final static int INITIAL_BLACKLIST = 10;
    public final static int FINAL_BLACKLIST = 11;
    public final static int DOMAIN_BLACKLIST = 12;
    public final static int DOMAIN_INITIAL_BLACKLIST = 13;
    public final static int DOMAIN_FINAL_BLACKLIST = 14;
    public final static int DOMAIN_REGULAR_EXPRESSION_BLACKLIST = 15;
    public final static int THIRD_PARTY_BLACKLIST = 16;
    public final static int THIRD_PARTY_INITIAL_BLACKLIST = 17;
    public final static int THIRD_PARTY_DOMAIN_BLACKLIST = 18;
    public final static int THIRD_PARTY_DOMAIN_INITIAL_BLACKLIST = 19;
    public final static int THIRD_PARTY_REGULAR_EXPRESSION_BLACKLIST = 20;
    public final static int THIRD_PARTY_DOMAIN_REGULAR_EXPRESSION_BLACKLIST = 21;
    public final static int REGULAR_EXPRESSION_BLACKLIST = 22;

    // `blockAllThirdPartyRequests` is public static so it can be accessed from `RequestsActivity`.
    // It is also used in `onCreate()`, `onPrepareOptionsMenu()`, `onOptionsItemSelected()`, and `applyAppSettings()`
    public static boolean blockAllThirdPartyRequests;

    // `currentBookmarksFolder` is public static so it can be accessed from `BookmarksActivity`.  It is also used in `onCreate()`, `onBackPressed()`, `onCreateBookmark()`, `onCreateBookmarkFolder()`,
    // `onSaveEditBookmark()`, `onSaveEditBookmarkFolder()`, and `loadBookmarksFolder()`.
    public static String currentBookmarksFolder;

    // `domainSettingsDatabaseId` is public static so it can be accessed from `PinnedMismatchDialog`.  It is also used in `onCreate()`, `onOptionsItemSelected()`, and `applyDomainSettings()`.
    public static int domainSettingsDatabaseId;

    // The pinned variables are public static so they can be accessed from `PinnedMismatchDialog`.  They are also used in `onCreate()`, `applyDomainSettings()`, and `checkPinnedMismatch()`.
    public static String pinnedSslIssuedToCName;
    public static String pinnedSslIssuedToOName;
    public static String pinnedSslIssuedToUName;
    public static String pinnedSslIssuedByCName;
    public static String pinnedSslIssuedByOName;
    public static String pinnedSslIssuedByUName;
    public static Date pinnedSslStartDate;
    public static Date pinnedSslEndDate;
    public static String pinnedHostIpAddresses;

    // The user agent constants are public static so they can be accessed from `SettingsFragment`, `DomainsActivity`, and `DomainSettingsFragment`.
    public final static int UNRECOGNIZED_USER_AGENT = -1;
    public final static int SETTINGS_WEBVIEW_DEFAULT_USER_AGENT = 1;
    public final static int SETTINGS_CUSTOM_USER_AGENT = 12;
    public final static int DOMAINS_SYSTEM_DEFAULT_USER_AGENT = 0;
    public final static int DOMAINS_WEBVIEW_DEFAULT_USER_AGENT = 2;
    public final static int DOMAINS_CUSTOM_USER_AGENT = 13;



    // `urlIsLoading` is used in `onCreate()`, `onCreateOptionsMenu()`, `loadUrl()`, `applyDomainSettings()`, and `GetHostIpAddresses`.
    private static boolean urlIsLoading;

    // `gettingIpAddresses` is used in `onCreate() and `GetHostIpAddresses`.
    private static boolean gettingIpAddresses;

    // `pinnedDomainSslCertificate` is used in `onCreate()`, `applyDomainSettings()`, and `checkPinnedMismatch()`.
    private static boolean pinnedSslCertificate;

    // `pinnedIpAddress` is used in `applyDomainSettings()` and `checkPinnedMismatch()`.
    private static boolean pinnedIpAddresses;

    // `ignorePinnedDomainInformation` is used in `onSslMismatchProceed()`, `applyDomainSettings()`, and `checkPinnedMismatch()`.
    private static boolean ignorePinnedDomainInformation;

    // The fragment manager is initialized in `onCreate()` and accessed from the static `checkPinnedMismatch()`.
    private static FragmentManager fragmentManager;


    // `navigatingHistory` is used in `onCreate()`, `onNavigationItemSelected()`, `onSslMismatchBack()`, and `applyDomainSettings()`.
    private boolean navigatingHistory;

    // `mainWebView` is used in `onCreate()`, `onPrepareOptionsMenu()`, `onOptionsItemSelected()`, `onNavigationItemSelected()`, `onRestart()`, `onCreateContextMenu()`, `findPreviousOnPage()`,
    // `findNextOnPage()`, `closeFindOnPage()`, `loadUrlFromTextBox()`, `onSslMismatchBack()`, and `applyProxyThroughOrbot()`.
    private WebView mainWebView;

    // `fullScreenVideoFrameLayout` is used in `onCreate()` and `onConfigurationChanged()`.
    private FrameLayout fullScreenVideoFrameLayout;

    // `urlAppBarRelativeLayout` is used in `onCreate()` and `applyDomainSettings()`.
    private RelativeLayout urlAppBarRelativeLayout;

    // `favoriteIconImageView` is used in `onCreate()` and `applyDomainSettings()`
    private ImageView favoriteIconImageView;

    // `cookieManager` is used in `onCreate()`, `onOptionsItemSelected()`, and `onNavigationItemSelected()`, `loadUrlFromTextBox()`, `onDownloadImage()`, `onDownloadFile()`, and `onRestart()`.
    private CookieManager cookieManager;

    // `customHeader` is used in `onCreate()`, `onOptionsItemSelected()`, `onCreateContextMenu()`, and `loadUrl()`.
    private final Map<String, String> customHeaders = new HashMap<>();

    // `javaScriptEnabled` is also used in `onCreate()`, `onPrepareOptionsMenu()`, `onOptionsItemSelected()`, `applyDomainSettings()`, and `updatePrivacyIcons()`.
    private boolean javaScriptEnabled;

    // `firstPartyCookiesEnabled` is used in `onCreate()`, `onPrepareOptionsMenu()`, `onOptionsItemSelected()`, `onDownloadImage()`, `onDownloadFile()`, and `applyDomainSettings()`.
    private boolean firstPartyCookiesEnabled;

    // `thirdPartyCookiesEnabled` used in `onCreate()`, `onPrepareOptionsMenu()`, `onPrepareOptionsMenu()`, `onOptionsItemSelected()`, and `applyDomainSettings()`.
    private boolean thirdPartyCookiesEnabled;

    // `domStorageEnabled` is used in `onCreate()`, `onPrepareOptionsMenu()`, `onOptionsItemSelected()`, and `applyDomainSettings()`.
    private boolean domStorageEnabled;

    // `saveFormDataEnabled` is used in `onCreate()`, `onPrepareOptionsMenu()`, `onOptionsItemSelected()`, and `applyDomainSettings()`.  It can be removed once the minimum API >= 26.
    private boolean saveFormDataEnabled;

    // `nightMode` is used in `onCreate()`, `onPrepareOptionsMenu()`, `onOptionsItemSelected()`, and  `applyDomainSettings()`.
    private boolean nightMode;

    // 'homepage' is used in `onCreate()`, `onNavigationItemSelected()`, and `applyProxyThroughOrbot()`.
    private String homepage;

    // `searchURL` is used in `loadURLFromTextBox()` and `applyProxyThroughOrbot()`.
    private String searchURL;

    // `mainMenu` is used in `onCreateOptionsMenu()` and `updatePrivacyIcons()`.
    private Menu mainMenu;

    // `refreshMenuItem` is used in `onCreate()` and `onCreateOptionsMenu()`.
    private MenuItem refreshMenuItem;

    // The blocklist menu items are used in `onCreate()`, `onCreateOptionsMenu()`, and `onPrepareOptionsMenu()`.
    private MenuItem blocklistsMenuItem;
    private MenuItem easyListMenuItem;
    private MenuItem easyPrivacyMenuItem;
    private MenuItem fanboysAnnoyanceListMenuItem;
    private MenuItem fanboysSocialBlockingListMenuItem;
    private MenuItem ultraPrivacyMenuItem;
    private MenuItem blockAllThirdPartyRequestsMenuItem;

    // The blocklist variables are used in `onCreate()`, `onPrepareOptionsMenu()`, `onOptionsItemSelected()`, and `applyAppSettings()`.
    private boolean easyListEnabled;
    private boolean easyPrivacyEnabled;
    private boolean fanboysAnnoyanceListEnabled;
    private boolean fanboysSocialBlockingListEnabled;
    private boolean ultraPrivacyEnabled;

    // `webViewDefaultUserAgent` is used in `onCreate()` and `onPrepareOptionsMenu()`.
    private String webViewDefaultUserAgent;

    // `defaultCustomUserAgentString` is used in `onPrepareOptionsMenu()` and `applyDomainSettings()`.
    private String defaultCustomUserAgentString;

    // `privacyBrowserRuntime` is used in `onCreate()`, `onOptionsItemSelected()`, and `applyAppSettings()`.
    private Runtime privacyBrowserRuntime;

    // `proxyThroughOrbot` is used in `onRestart()`, `onOptionsItemSelected()`, `applyAppSettings()`, and `applyProxyThroughOrbot()`.
    private boolean proxyThroughOrbot;

    // `incognitoModeEnabled` is used in `onCreate()` and `applyAppSettings()`.
    private boolean incognitoModeEnabled;

    // `fullScreenBrowsingModeEnabled` is used in `onCreate()` and `applyAppSettings()`.
    private boolean fullScreenBrowsingModeEnabled;

    // `inFullScreenBrowsingMode` is used in `onCreate()`, `onConfigurationChanged()`, and `applyAppSettings()`.
    private boolean inFullScreenBrowsingMode;

    // `hideSystemBarsOnFullscreen` is used in `onCreate()` and `applyAppSettings()`.
    private boolean hideSystemBarsOnFullscreen;

    // `translucentNavigationBarOnFullscreen` is used in `onCreate()` and `applyAppSettings()`.
    private boolean translucentNavigationBarOnFullscreen;

    // `reapplyDomainSettingsOnRestart` is used in `onCreate()`, `onOptionsItemSelected()`, `onNavigationItemSelected()`, `onRestart()`, and `onAddDomain()`, .
    private boolean reapplyDomainSettingsOnRestart;

    // `reapplyAppSettingsOnRestart` is used in `onNavigationItemSelected()` and `onRestart()`.
    private boolean reapplyAppSettingsOnRestart;

    // `displayingFullScreenVideo` is used in `onCreate()` and `onResume()`.
    private boolean displayingFullScreenVideo;

    // `downloadWithExternalApp` is used in `onCreate()`, `onCreateContextMenu()`, and `applyDomainSettings()`.
    private boolean downloadWithExternalApp;

    // `currentDomainName` is used in `onCreate()`, `onOptionsItemSelected()`, `onNavigationItemSelected()`, `onAddDomain()`, and `applyDomainSettings()`.
    private String currentDomainName;

    // `orbotStatusBroadcastReceiver` is used in `onCreate()` and `onDestroy()`.
    private BroadcastReceiver orbotStatusBroadcastReceiver;

    // `waitingForOrbot` is used in `onCreate()`, `onResume()`, and `applyProxyThroughOrbot()`.
    private boolean waitingForOrbot;

    // `domainSettingsApplied` is used in `prepareOptionsMenu()` and `applyDomainSettings()`.
    private boolean domainSettingsApplied;

    // `domainSettingsJavaScriptEnabled` is used in `onOptionsItemSelected()` and `applyDomainSettings()`.
    private Boolean domainSettingsJavaScriptEnabled;

    // `waitingForOrbotHtmlString` is used in `onCreate()` and `applyProxyThroughOrbot()`.
    private String waitingForOrbotHtmlString;

    // `privateDataDirectoryString` is used in `onCreate()`, `onOptionsItemSelected()`, and `onNavigationItemSelected()`.
    private String privateDataDirectoryString;

    // `findOnPageLinearLayout` is used in `onCreate()`, `onOptionsItemSelected()`, and `closeFindOnPage()`.
    private LinearLayout findOnPageLinearLayout;

    // `findOnPageEditText` is used in `onCreate()`, `onOptionsItemSelected()`, and `closeFindOnPage()`.
    private EditText findOnPageEditText;

    // `displayAdditionalAppBarIcons` is used in `onCreate()` and `onCreateOptionsMenu()`.
    private boolean displayAdditionalAppBarIcons;

    // The action bar drawer toggle is initialized in `onCreate()` and used in `onPostCreate()`.
    private ActionBarDrawerToggle actionBarDrawerToggle;

    // `urlTextBox` is used in `onCreate()`, `onOptionsItemSelected()`, `loadUrlFromTextBox()`, `loadUrl()`, and `highlightUrlText()`.
    private EditText urlTextBox;

    // The color spans are used in `onCreate()` and `highlightUrlText()`.
    private ForegroundColorSpan redColorSpan;
    private ForegroundColorSpan initialGrayColorSpan;
    private ForegroundColorSpan finalGrayColorSpan;

    // The drawer header padding variables are used in `onCreate()` and `onConfigurationChanged()`.
    private int drawerHeaderPaddingLeftAndRight;
    private int drawerHeaderPaddingTop;
    private int drawerHeaderPaddingBottom;

    // `sslErrorHandler` is used in `onCreate()`, `onSslErrorCancel()`, and `onSslErrorProceed`.
    private SslErrorHandler sslErrorHandler;

    // `httpAuthHandler` is used in `onCreate()`, `onHttpAuthenticationCancel()`, and `onHttpAuthenticationProceed()`.
    private static HttpAuthHandler httpAuthHandler;

    // `inputMethodManager` is used in `onOptionsItemSelected()`, `loadUrlFromTextBox()`, and `closeFindOnPage()`.
    private InputMethodManager inputMethodManager;

    // `bookmarksDatabaseHelper` is used in `onCreate()`, `onDestroy`, `onOptionsItemSelected()`, `onCreateBookmark()`, `onCreateBookmarkFolder()`, `onSaveEditBookmark()`, `onSaveEditBookmarkFolder()`,
    // and `loadBookmarksFolder()`.
    private BookmarksDatabaseHelper bookmarksDatabaseHelper;

    // `bookmarksListView` is used in `onCreate()`, `onCreateBookmark()`, `onCreateBookmarkFolder()`, and `loadBookmarksFolder()`.
    private ListView bookmarksListView;

    // `bookmarksTitleTextView` is used in `onCreate()` and `loadBookmarksFolder()`.
    private TextView bookmarksTitleTextView;

    // `bookmarksCursor` is used in `onDestroy()`, `onOptionsItemSelected()`, `onCreateBookmark()`, `onCreateBookmarkFolder()`, `onSaveEditBookmark()`, `onSaveEditBookmarkFolder()`, and `loadBookmarksFolder()`.
    private Cursor bookmarksCursor;

    // `bookmarksCursorAdapter` is used in `onCreateBookmark()`, `onCreateBookmarkFolder()` `onSaveEditBookmark()`, `onSaveEditBookmarkFolder()`, and `loadBookmarksFolder()`.
    private CursorAdapter bookmarksCursorAdapter;

    // `oldFolderNameString` is used in `onCreate()` and `onSaveEditBookmarkFolder()`.
    private String oldFolderNameString;

    // `fileChooserCallback` is used in `onCreate()` and `onActivityResult()`.
    private ValueCallback<Uri[]> fileChooserCallback;

    // The download strings are used in `onCreate()` and `onRequestPermissionResult()`.
    private String downloadUrl;
    private String downloadContentDisposition;
    private long downloadContentLength;

    // `downloadImageUrl` is used in `onCreateContextMenu()` and `onRequestPermissionResult()`.
    private String downloadImageUrl;

    // The user agent variables are used in `onCreate()` and `applyDomainSettings()`.
    private ArrayAdapter<CharSequence> userAgentNamesArray;
    private String[] userAgentDataArray;

    // The request codes are used in `onCreate()`, `onCreateContextMenu()`, `onCloseDownloadLocationPermissionDialog()`, and `onRequestPermissionResult()`.
    private final int DOWNLOAD_FILE_REQUEST_CODE = 1;
    private final int DOWNLOAD_IMAGE_REQUEST_CODE = 2;

    @Override
    // Remove Android Studio's warning about the dangers of using SetJavaScriptEnabled.  The whole premise of Privacy Browser is built around an understanding of these dangers.
    // Also, remove the warning about needing to override `performClick()` when using an `OnTouchListener` with `WebView`.
    @SuppressLint({"SetJavaScriptEnabled", "ClickableViewAccessibility"})
    // Remove Android Studio's warning about deprecations.  The deprecated `getColor()` must be used until API >= 23.
    @SuppressWarnings("deprecation")
    protected void onCreate(Bundle savedInstanceState) {
        // Get a handle for the shared preferences.
        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);

        // Get the theme and screenshot preferences.
        darkTheme = sharedPreferences.getBoolean("dark_theme", false);
        allowScreenshots = sharedPreferences.getBoolean("allow_screenshots", false);

        // Disable screenshots if not allowed.
        if (!allowScreenshots) {
            getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE);
        }

        // Set the activity theme.
        if (darkTheme) {
            setTheme(R.style.PrivacyBrowserDark);
        } else {
            setTheme(R.style.PrivacyBrowserLight);
        }

        // Run the default commands.
        super.onCreate(savedInstanceState);

        // Set the content view.
        setContentView(R.layout.main_drawerlayout);

        // Get handles for views, resources, and managers.
        Resources resources = getResources();
        fragmentManager = getSupportFragmentManager();
        inputMethodManager = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
        Toolbar toolbar = findViewById(R.id.toolbar);

        // Set the action bar.  `SupportActionBar` must be used until the minimum API is >= 21.
        setSupportActionBar(toolbar);
        ActionBar actionBar = getSupportActionBar();

        // This is needed to get rid of the Android Studio warning that the action bar might be null.
        assert actionBar != null;

        // Add the custom `url_app_bar` layout, which shows the favorite icon and the URL text bar.
        actionBar.setCustomView(R.layout.url_app_bar);
        actionBar.setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM);

        // Initialize the foreground color spans for highlighting the URLs.  We have to use the deprecated `getColor()` until API >= 23.
        redColorSpan = new ForegroundColorSpan(resources.getColor(R.color.red_a700));
        initialGrayColorSpan = new ForegroundColorSpan(resources.getColor(R.color.gray_500));
        finalGrayColorSpan = new ForegroundColorSpan(resources.getColor(R.color.gray_500));

        // Get a handle for `urlTextBox`.
        urlTextBox = findViewById(R.id.url_edittext);

        // Remove the formatting from `urlTextBar` when the user is editing the text.
        urlTextBox.setOnFocusChangeListener((View v, boolean hasFocus) -> {
            if (hasFocus) {  // The user is editing the URL text box.
                // Remove the highlighting.
                urlTextBox.getText().removeSpan(redColorSpan);
                urlTextBox.getText().removeSpan(initialGrayColorSpan);
                urlTextBox.getText().removeSpan(finalGrayColorSpan);
            } else {  // The user has stopped editing the URL text box.
                // Move to the beginning of the string.
                urlTextBox.setSelection(0);

                // Reapply the highlighting.
                highlightUrlText();
            }
        });

        // Set the go button on the keyboard to load the URL in `urlTextBox`.
        urlTextBox.setOnKeyListener((View v, int keyCode, KeyEvent event) -> {
            // If the event is a key-down event on the `enter` button, load the URL.
            if ((event.getAction() == KeyEvent.ACTION_DOWN) && (keyCode == KeyEvent.KEYCODE_ENTER)) {
                // Load the URL into the mainWebView and consume the event.
                loadUrlFromTextBox();

                // If the enter key was pressed, consume the event.
                return true;
            } else {
                // If any other key was pressed, do not consume the event.
                return false;
            }
        });

        // Set `waitingForOrbotHTMLString`.
        waitingForOrbotHtmlString = "<html><body><br/><center><h1>" + getString(R.string.waiting_for_orbot) + "</h1></center></body></html>";

        // Initialize `currentDomainName`, `orbotStatus`, and `waitingForOrbot`.
        currentDomainName = "";
        orbotStatus = "unknown";
        waitingForOrbot = false;

        // Create an Orbot status `BroadcastReceiver`.
        orbotStatusBroadcastReceiver = new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
                // Store the content of the status message in `orbotStatus`.
                orbotStatus = intent.getStringExtra("org.torproject.android.intent.extra.STATUS");

                // If Privacy Browser is waiting on Orbot, load the website now that Orbot is connected.
                if (orbotStatus.equals("ON") && waitingForOrbot) {
                    // Reset `waitingForOrbot`.
                    waitingForOrbot = false;

                    // Load `formattedUrlString
                    loadUrl(formattedUrlString);
                }
            }
        };

        // Register `orbotStatusBroadcastReceiver` on `this` context.
        this.registerReceiver(orbotStatusBroadcastReceiver, new IntentFilter("org.torproject.android.intent.action.STATUS"));

        // Get handles for views that need to be modified.
        DrawerLayout drawerLayout = findViewById(R.id.drawerlayout);
        CoordinatorLayout coordinatorLayout = findViewById(R.id.coordinatorlayout);
        bookmarksListView = findViewById(R.id.bookmarks_drawer_listview);
        bookmarksTitleTextView = findViewById(R.id.bookmarks_title_textview);
        FloatingActionButton launchBookmarksActivityFab = findViewById(R.id.launch_bookmarks_activity_fab);
        FloatingActionButton createBookmarkFolderFab = findViewById(R.id.create_bookmark_folder_fab);
        FloatingActionButton createBookmarkFab = findViewById(R.id.create_bookmark_fab);
        SwipeRefreshLayout swipeRefreshLayout = findViewById(R.id.swiperefreshlayout);
        mainWebView = findViewById(R.id.main_webview);
        findOnPageLinearLayout = findViewById(R.id.find_on_page_linearlayout);
        findOnPageEditText = findViewById(R.id.find_on_page_edittext);
        fullScreenVideoFrameLayout = findViewById(R.id.full_screen_video_framelayout);
        urlAppBarRelativeLayout = findViewById(R.id.url_app_bar_relativelayout);
        favoriteIconImageView = findViewById(R.id.favorite_icon);

        // Set the bookmarks drawer resources according to the theme.  This can't be done in the layout due to compatibility issues with the `DrawerLayout` support widget.
        if (darkTheme) {
            launchBookmarksActivityFab.setImageDrawable(resources.getDrawable(R.drawable.bookmarks_dark));
            createBookmarkFolderFab.setImageDrawable(resources.getDrawable(R.drawable.create_folder_dark));
            createBookmarkFab.setImageDrawable(resources.getDrawable(R.drawable.create_bookmark_dark));
            bookmarksListView.setBackgroundColor(resources.getColor(R.color.gray_850));
        } else {
            launchBookmarksActivityFab.setImageDrawable(resources.getDrawable(R.drawable.bookmarks_light));
            createBookmarkFolderFab.setImageDrawable(resources.getDrawable(R.drawable.create_folder_light));
            createBookmarkFab.setImageDrawable(resources.getDrawable(R.drawable.create_bookmark_light));
            bookmarksListView.setBackgroundColor(resources.getColor(R.color.white));
        }

        // Set the launch bookmarks activity FAB to launch the bookmarks activity.
        launchBookmarksActivityFab.setOnClickListener(v -> {
            // Create an intent to launch the bookmarks activity.
            Intent bookmarksIntent = new Intent(getApplicationContext(), BookmarksActivity.class);

            // Include the current folder with the `Intent`.
            bookmarksIntent.putExtra("Current Folder", currentBookmarksFolder);

            // Make it so.
            startActivity(bookmarksIntent);
        });

        // Set the create new bookmark folder FAB to display an alert dialog.
        createBookmarkFolderFab.setOnClickListener(v -> {
            // Show the create bookmark folder dialog and name the instance `@string/create_folder`.
            DialogFragment createBookmarkFolderDialog = new CreateBookmarkFolderDialog();
            createBookmarkFolderDialog.show(fragmentManager, resources.getString(R.string.create_folder));
        });

        // Set the create new bookmark FAB to display an alert dialog.
        createBookmarkFab.setOnClickListener(view -> {
            // Show the create bookmark dialog and name the instance `@string/create_bookmark`.
            DialogFragment createBookmarkDialog = new CreateBookmarkDialog();
            createBookmarkDialog.show(fragmentManager, resources.getString(R.string.create_bookmark));
        });

        // Create a double-tap listener to toggle full-screen mode.
        final GestureDetector gestureDetector = new GestureDetector(this, new GestureDetector.SimpleOnGestureListener() {
            // Override `onDoubleTap()`.  All other events are handled using the default settings.
            @Override
            public boolean onDoubleTap(MotionEvent event) {
                if (fullScreenBrowsingModeEnabled) {  // Only process the double-tap if full screen browsing mode is enabled.
                    // Toggle `inFullScreenBrowsingMode`.
                    inFullScreenBrowsingMode = !inFullScreenBrowsingMode;

                    if (inFullScreenBrowsingMode) {  // Switch to full screen mode.
                        // Hide the action bar.
                        actionBar.hide();

                        // Hide the banner ad in the free flavor.
                        if (BuildConfig.FLAVOR.contentEquals("free")) {
                            // The AdView is destroyed and recreated, which changes the ID, every time it is reloaded to handle possible rotations.
                            AdHelper.hideAd(findViewById(R.id.adview));
                        }

                        // Modify the system bars.
                        if (hideSystemBarsOnFullscreen) {  // Hide everything.
                            // Remove the translucent overlays.
                            getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);

                            // Remove the translucent status bar overlay on the `Drawer Layout`, which is special and needs its own command.
                            drawerLayout.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);

                            /* SYSTEM_UI_FLAG_FULLSCREEN hides the status bar at the top of the screen.
                             * SYSTEM_UI_FLAG_HIDE_NAVIGATION hides the navigation bar on the bottom or right of the screen.
                             * SYSTEM_UI_FLAG_IMMERSIVE_STICKY makes the status and navigation bars translucent and automatically re-hides them after they are shown.
                             */
                            coordinatorLayout.setSystemUiVisibility(View.SYSTEM_UI_FLAG_FULLSCREEN | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);

                            // Set the coordinator layout to fill the entire screen.
                            coordinatorLayout.setFitsSystemWindows(false);
                        } else {  // Hide everything except the status and navigation bars.
                            // Set the coordinator layout to fill the entire screen.
                            coordinatorLayout.setFitsSystemWindows(false);

                            // There is an Android Support Library bug that causes a scrim to print on the right side of the `Drawer Layout` when the navigation bar is displayed on the right of the screen.
                            if (translucentNavigationBarOnFullscreen) {
                                // Set the navigation bar to be translucent.
                                getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
                            }
                        }
                    } else {  // Switch to normal viewing mode.
                        // Show the action bar.
                        actionBar.show();

                        // Show the `BannerAd` in the free flavor.
                        if (BuildConfig.FLAVOR.contentEquals("free")) {
                            // Reload the ad.  The AdView is destroyed and recreated, which changes the ID, every time it is reloaded to handle possible rotations.
                            AdHelper.loadAd(findViewById(R.id.adview), getApplicationContext(), getString(R.string.ad_unit_id));
                        }

                        // Remove the translucent navigation bar flag if it is set.
                        getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);

                        // Add the translucent status flag if it is unset.  This also resets `drawerLayout's` `View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN`.
                        getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);

                        // Remove any `SYSTEM_UI` flags from the coordinator layout.
                        coordinatorLayout.setSystemUiVisibility(0);

                        // Constrain the coordinator layout inside the status and navigation bars.
                        coordinatorLayout.setFitsSystemWindows(true);
                    }

                    // Consume the double-tap.
                    return true;
                } else { // Do not consume the double-tap because full screen browsing mode is disabled.
                    return false;
                }
            }
        });

        // Pass all touch events on `mainWebView` through `gestureDetector` to check for double-taps.
        mainWebView.setOnTouchListener((View view, MotionEvent event) -> {
            // Call `performClick()` on the view, which is required for accessibility.
            view.performClick();

            // Send the `event` to `gestureDetector`.
            return gestureDetector.onTouchEvent(event);
        });

        // Update `findOnPageCountTextView`.
        mainWebView.setFindListener(new WebView.FindListener() {
            // Get a handle for `findOnPageCountTextView`.
            final TextView findOnPageCountTextView = findViewById(R.id.find_on_page_count_textview);

            @Override
            public void onFindResultReceived(int activeMatchOrdinal, int numberOfMatches, boolean isDoneCounting) {
                if ((isDoneCounting) && (numberOfMatches == 0)) {  // There are no matches.
                    // Set `findOnPageCountTextView` to `0/0`.
                    findOnPageCountTextView.setText(R.string.zero_of_zero);
                } else if (isDoneCounting) {  // There are matches.
                    // `activeMatchOrdinal` is zero-based.
                    int activeMatch = activeMatchOrdinal + 1;

                    // Build the match string.
                    String matchString = activeMatch + "/" + numberOfMatches;

                    // Set `findOnPageCountTextView`.
                    findOnPageCountTextView.setText(matchString);
                }
            }
        });

        // Search for the string on the page whenever a character changes in the `findOnPageEditText`.
        findOnPageEditText.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {
                // Do nothing.
            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {
                // Do nothing.
            }

            @Override
            public void afterTextChanged(Editable s) {
                // Search for the text in `mainWebView`.
                mainWebView.findAllAsync(findOnPageEditText.getText().toString());
            }
        });

        // Set the `check mark` button for the `findOnPageEditText` keyboard to close the soft keyboard.
        findOnPageEditText.setOnKeyListener((v, keyCode, event) -> {
            if ((event.getAction() == KeyEvent.ACTION_DOWN) && (keyCode == KeyEvent.KEYCODE_ENTER)) {  // The `enter` key was pressed.
                // Hide the soft keyboard.  `0` indicates no additional flags.
                inputMethodManager.hideSoftInputFromWindow(mainWebView.getWindowToken(), 0);

                // Consume the event.
                return true;
            } else {  // A different key was pressed.
                // Do not consume the event.
                return false;
            }
        });

        // Implement swipe to refresh.
        swipeRefreshLayout.setOnRefreshListener(() -> mainWebView.reload());

        // Set the swipe to refresh color according to the theme.
        if (darkTheme) {
            swipeRefreshLayout.setColorSchemeResources(R.color.blue_600);
            swipeRefreshLayout.setProgressBackgroundColorSchemeResource(R.color.gray_850);
        } else {
            swipeRefreshLayout.setColorSchemeResources(R.color.blue_700);
        }

        // `DrawerTitle` identifies the `DrawerLayouts` in accessibility mode.
        drawerLayout.setDrawerTitle(GravityCompat.START, getString(R.string.navigation_drawer));
        drawerLayout.setDrawerTitle(GravityCompat.END, getString(R.string.bookmarks));

        // Listen for touches on the navigation menu.
        final NavigationView navigationView = findViewById(R.id.navigationview);
        navigationView.setNavigationItemSelectedListener(this);

        // Get handles for `navigationMenu` and the back and forward menu items.  The menu is zero-based, so items 1, 2, and 3 are the second, third, and fourth entries in the menu.
        final Menu navigationMenu = navigationView.getMenu();
        final MenuItem navigationBackMenuItem = navigationMenu.getItem(1);
        final MenuItem navigationForwardMenuItem = navigationMenu.getItem(2);
        final MenuItem navigationHistoryMenuItem = navigationMenu.getItem(3);
        final MenuItem navigationRequestsMenuItem = navigationMenu.getItem(4);

        // Initialize the bookmarks database helper.  The `0` specifies a database version, but that is ignored and set instead using a constant in `BookmarksDatabaseHelper`.
        bookmarksDatabaseHelper = new BookmarksDatabaseHelper(this, null, null, 0);

        // Initialize `currentBookmarksFolder`.  `""` is the home folder in the database.
        currentBookmarksFolder = "";

        // Load the home folder, which is `""` in the database.
        loadBookmarksFolder();

        bookmarksListView.setOnItemClickListener((parent, view, position, id) -> {
            // Convert the id from long to int to match the format of the bookmarks database.
            int databaseID = (int) id;

            // Get the bookmark cursor for this ID and move it to the first row.
            Cursor bookmarkCursor = bookmarksDatabaseHelper.getBookmark(databaseID);
            bookmarkCursor.moveToFirst();

            // Act upon the bookmark according to the type.
            if (bookmarkCursor.getInt(bookmarkCursor.getColumnIndex(BookmarksDatabaseHelper.IS_FOLDER)) == 1) {  // The selected bookmark is a folder.
                // Store the new folder name in `currentBookmarksFolder`.
                currentBookmarksFolder = bookmarkCursor.getString(bookmarkCursor.getColumnIndex(BookmarksDatabaseHelper.BOOKMARK_NAME));

                // Load the new folder.
                loadBookmarksFolder();
            } else {  // The selected bookmark is not a folder.
                // Load the bookmark URL.
                loadUrl(bookmarkCursor.getString(bookmarkCursor.getColumnIndex(BookmarksDatabaseHelper.BOOKMARK_URL)));

                // Close the bookmarks drawer.
                drawerLayout.closeDrawer(GravityCompat.END);
            }

            // Close the `Cursor`.
            bookmarkCursor.close();
        });

        bookmarksListView.setOnItemLongClickListener((parent, view, position, id) -> {
            // Convert the database ID from `long` to `int`.
            int databaseId = (int) id;

            // Find out if the selected bookmark is a folder.
            boolean isFolder = bookmarksDatabaseHelper.isFolder(databaseId);

            if (isFolder) {
                // Save the current folder name, which is used in `onSaveEditBookmarkFolder()`.
                oldFolderNameString = bookmarksCursor.getString(bookmarksCursor.getColumnIndex(BookmarksDatabaseHelper.BOOKMARK_NAME));

                // Show the edit bookmark folder `AlertDialog` and name the instance `@string/edit_folder`.
                DialogFragment editBookmarkFolderDialog = EditBookmarkFolderDialog.folderDatabaseId(databaseId);
                editBookmarkFolderDialog.show(fragmentManager, resources.getString(R.string.edit_folder));
            } else {
                // Show the edit bookmark `AlertDialog` and name the instance `@string/edit_bookmark`.
                DialogFragment editBookmarkDialog = EditBookmarkDialog.bookmarkDatabaseId(databaseId);
                editBookmarkDialog.show(fragmentManager, resources.getString(R.string.edit_bookmark));
            }

            // Consume the event.
            return true;
        });

        // Get the status bar pixel size.
        int statusBarResourceId = resources.getIdentifier("status_bar_height", "dimen", "android");
        int statusBarPixelSize = resources.getDimensionPixelSize(statusBarResourceId);

        // Get the resource density.
        float screenDensity = resources.getDisplayMetrics().density;

        // Calculate the drawer header padding.  This is used to move the text in the drawer headers below any cutouts.
        drawerHeaderPaddingLeftAndRight = (int) (15 * screenDensity);
        drawerHeaderPaddingTop = statusBarPixelSize + (int) (4 * screenDensity);
        drawerHeaderPaddingBottom = (int) (8 * screenDensity);

        // The drawer listener is used to update the navigation menu.`
        drawerLayout.addDrawerListener(new DrawerLayout.DrawerListener() {
            @Override
            public void onDrawerSlide(@NonNull View drawerView, float slideOffset) {
            }

            @Override
            public void onDrawerOpened(@NonNull View drawerView) {
            }

            @Override
            public void onDrawerClosed(@NonNull View drawerView) {
            }

            @Override
            public void onDrawerStateChanged(int newState) {
                if ((newState == DrawerLayout.STATE_SETTLING) || (newState == DrawerLayout.STATE_DRAGGING)) {  // A drawer is opening or closing.
                    // Get handles for the drawer headers.
                    TextView navigationHeaderTextView = findViewById(R.id.navigationText);
                    TextView bookmarksHeaderTextView = findViewById(R.id.bookmarks_title_textview);

                    // Apply the navigation header paddings if the view is not null (sometimes it is null if another activity has already started).  This moves the text in the header below any cutouts.
                    if (navigationHeaderTextView != null) {
                        navigationHeaderTextView.setPadding(drawerHeaderPaddingLeftAndRight, drawerHeaderPaddingTop, drawerHeaderPaddingLeftAndRight, drawerHeaderPaddingBottom);
                    }

                    // Apply the bookmarks header paddings if the view is not null (sometimes it is null if another activity has already started).  This moves the text in the header below any cutouts.
                    if (bookmarksHeaderTextView != null) {
                        bookmarksHeaderTextView.setPadding(drawerHeaderPaddingLeftAndRight, drawerHeaderPaddingTop, drawerHeaderPaddingLeftAndRight, drawerHeaderPaddingBottom);
                    }

                    // Update the back, forward, history, and requests menu items.
                    navigationBackMenuItem.setEnabled(mainWebView.canGoBack());
                    navigationForwardMenuItem.setEnabled(mainWebView.canGoForward());
                    navigationHistoryMenuItem.setEnabled((mainWebView.canGoBack() || mainWebView.canGoForward()));
                    navigationRequestsMenuItem.setTitle(getString(R.string.requests) + " - " + blockedRequests);

                    // Hide the keyboard (if displayed).
                    inputMethodManager.hideSoftInputFromWindow(mainWebView.getWindowToken(), 0);

                    // Clear the focus from from the URL text box and the WebView.  This removes any text selection markers and context menus, which otherwise draw above the open drawers.
                    urlTextBox.clearFocus();
                    mainWebView.clearFocus();
                }
            }
        });

        // Create the hamburger icon at the start of the AppBar.
        actionBarDrawerToggle = new ActionBarDrawerToggle(this, drawerLayout, toolbar, R.string.open_navigation_drawer, R.string.close_navigation_drawer);

        // Get a handle for the progress bar.
        final ProgressBar progressBar = findViewById(R.id.progress_bar);

        mainWebView.setWebChromeClient(new WebChromeClient() {
            // Update the progress bar when a page is loading.
            @Override
            public void onProgressChanged(WebView view, int progress) {
                // Inject the night mode CSS if night mode is enabled.
                if (nightMode) {
                    // `background-color: #212121` sets the background to be dark gray.  `color: #BDBDBD` sets the text color to be light gray.  `box-shadow: none` removes a lower underline on links
                    // used by WordPress.  `text-decoration: none` removes all text underlines.  `text-shadow: none` removes text shadows, which usually have a hard coded color.
                    // `border: none` removes all borders, which can also be used to underline text.  `a {color: #1565C0}` sets links to be a dark blue.
                    // `::selection {background: #0D47A1}' sets the text selection highlight color to be a dark blue. `!important` takes precedent over any existing sub-settings.
                    mainWebView.evaluateJavascript("(function() {var parent = document.getElementsByTagName('head').item(0); var style = document.createElement('style'); style.type = 'text/css'; " +
                            "style.innerHTML = '* {background-color: #212121 !important; color: #BDBDBD !important; box-shadow: none !important; text-decoration: none !important;" +
                            "text-shadow: none !important; border: none !important;} a {color: #1565C0 !important;} ::selection {background: #0D47A1 !important;}'; parent.appendChild(style)})()", value -> {
                                // Initialize a handler to display `mainWebView`.
                                Handler displayWebViewHandler = new Handler();

                                // Setup a runnable to display `mainWebView` after a delay to allow the CSS to be applied.
                                Runnable displayWebViewRunnable = () -> {
                                    // Only display `mainWebView` if the progress bar is gone.  This prevents the display of the `WebView` while it is still loading.
                                    if (progressBar.getVisibility() == View.GONE) {
                                        mainWebView.setVisibility(View.VISIBLE);
                                    }
                                };

                                // Displaying of `mainWebView` after 500 milliseconds.
                                displayWebViewHandler.postDelayed(displayWebViewRunnable, 500);
                            });
                }

                // Update the progress bar.
                progressBar.setProgress(progress);

                // Set the visibility of the progress bar.
                if (progress < 100) {
                    // Show the progress bar.
                    progressBar.setVisibility(View.VISIBLE);
                } else {
                    // Hide the progress bar.
                    progressBar.setVisibility(View.GONE);

                    // Display `mainWebView` if night mode is disabled.
                    // Because of a race condition between `applyDomainSettings` and `onPageStarted`, when night mode is set by domain settings the `WebView` may be hidden even if night mode is not
                    // currently enabled.
                    if (!nightMode) {
                        mainWebView.setVisibility(View.VISIBLE);
                    }

                    //Stop the swipe to refresh indicator if it is running
                    swipeRefreshLayout.setRefreshing(false);
                }
            }

            // Set the favorite icon when it changes.
            @Override
            public void onReceivedIcon(WebView view, Bitmap icon) {
                // Only update the favorite icon if the website has finished loading.
                if (progressBar.getVisibility() == View.GONE) {
                    // Save a copy of the favorite icon.
                    favoriteIconBitmap = icon;

                    // Place the favorite icon in the appBar.
                    favoriteIconImageView.setImageBitmap(Bitmap.createScaledBitmap(icon, 64, 64, true));
                }
            }

            // Save a copy of the title when it changes.
            @Override
            public void onReceivedTitle(WebView view, String title) {
                // Save a copy of the title.
                webViewTitle = title;
            }

            // Enter full screen video.
            @Override
            public void onShowCustomView(View view, CustomViewCallback callback) {
                // Set the full screen video flag.
                displayingFullScreenVideo = true;

                // Pause the ad if this is the free flavor.
                if (BuildConfig.FLAVOR.contentEquals("free")) {
                    // The AdView is destroyed and recreated, which changes the ID, every time it is reloaded to handle possible rotations.
                    AdHelper.pauseAd(findViewById(R.id.adview));
                }

                // Remove the translucent overlays.
                getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);

                // Remove the translucent status bar overlay on the `Drawer Layout`, which is special and needs its own command.
                drawerLayout.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);

                /* SYSTEM_UI_FLAG_FULLSCREEN hides the status bar at the top of the screen.
                 * SYSTEM_UI_FLAG_HIDE_NAVIGATION hides the navigation bar on the bottom or right of the screen.
                 * SYSTEM_UI_FLAG_IMMERSIVE_STICKY makes the status and navigation bars translucent and automatically re-hides them after they are shown.
                 */
                coordinatorLayout.setSystemUiVisibility(View.SYSTEM_UI_FLAG_FULLSCREEN | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);

                // Set the coordinator layout to fill the entire screen.
                coordinatorLayout.setFitsSystemWindows(false);

                // Hide the action bar.
                actionBar.hide();

                // Disable the sliding drawers.
                drawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);

                // Add `view` to `fullScreenVideoFrameLayout` and display it on the screen.
                fullScreenVideoFrameLayout.addView(view);
                fullScreenVideoFrameLayout.setVisibility(View.VISIBLE);
            }

            // Exit full screen video.
            @Override
            public void onHideCustomView() {
                // Unset the full screen video flag.
                displayingFullScreenVideo = false;

                // Hide `fullScreenVideoFrameLayout`.
                fullScreenVideoFrameLayout.removeAllViews();
                fullScreenVideoFrameLayout.setVisibility(View.GONE);

                // Enable the sliding drawers.
                drawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED);

                // Apply the appropriate full screen mode the `SYSTEM_UI` flags.
                if (fullScreenBrowsingModeEnabled && inFullScreenBrowsingMode) {  // Privacy Browser is currently in full screen browsing mode.
                    if (hideSystemBarsOnFullscreen) {  // Hide everything.
                        // Remove the translucent navigation setting if it is currently flagged.
                        getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);

                        // Remove the translucent status bar overlay.
                        getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);

                        // Remove the translucent status bar overlay on the `Drawer Layout`, which is special and needs its own command.
                        drawerLayout.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);

                        /* SYSTEM_UI_FLAG_FULLSCREEN hides the status bar at the top of the screen.
                         * SYSTEM_UI_FLAG_HIDE_NAVIGATION hides the navigation bar on the bottom or right of the screen.
                         * SYSTEM_UI_FLAG_IMMERSIVE_STICKY makes the status and navigation bars translucent and automatically re-hides them after they are shown.
                         */
                        coordinatorLayout.setSystemUiVisibility(View.SYSTEM_UI_FLAG_FULLSCREEN | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);
                    } else {  // Hide everything except the status and navigation bars.
                        // Remove any `SYSTEM_UI` flags from the coordinator layout.
                        coordinatorLayout.setSystemUiVisibility(0);

                        // Add the translucent status flag if it is unset.
                        getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);

                        if (translucentNavigationBarOnFullscreen) {
                            // Set the navigation bar to be translucent.  This also resets `drawerLayout's` `View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN`.
                            getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
                        } else {
                            // Set the navigation bar to be black.
                            getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
                        }
                    }
                } else {  // Switch to normal viewing mode.
                    // Show the action bar if the find on page linear layout is not visible.
                    if (findOnPageLinearLayout.getVisibility() == View.GONE) {
                        actionBar.show();
                    }

                    // Show the `BannerAd` in the free flavor.
                    if (BuildConfig.FLAVOR.contentEquals("free")) {
                        // Initialize the ad.  The AdView is destroyed and recreated, which changes the ID, every time it is reloaded to handle possible rotations.
                        AdHelper.initializeAds(findViewById(R.id.adview), getApplicationContext(), fragmentManager, getString(R.string.google_app_id), getString(R.string.ad_unit_id));
                    }

                    // Remove any `SYSTEM_UI` flags from the coordinator layout.
                    coordinatorLayout.setSystemUiVisibility(0);

                    // Remove the translucent navigation bar flag if it is set.
                    getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);

                    // Add the translucent status flag if it is unset.  This also resets `drawerLayout's` `View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN`.
                    getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);

                    // Constrain the coordinator layout inside the status and navigation bars.
                    coordinatorLayout.setFitsSystemWindows(true);

                    // Show the action bar.
                    actionBar.show();
                }

                // Show the ad if this is the free flavor.
                if (BuildConfig.FLAVOR.contentEquals("free")) {
                    // Reload the ad.  The AdView is destroyed and recreated, which changes the ID, every time it is reloaded to handle possible rotations.
                    AdHelper.loadAd(findViewById(R.id.adview), getApplicationContext(), getString(R.string.ad_unit_id));
                }
            }

            // Upload files.
            @Override
            public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback, FileChooserParams fileChooserParams) {
                // Show the file chooser if the device is running API >= 21.
                if (Build.VERSION.SDK_INT >= 21) {
                    // Store the file path callback.
                    fileChooserCallback = filePathCallback;

                    // Create an intent to open a chooser based ont the file chooser parameters.
                    Intent fileChooserIntent = fileChooserParams.createIntent();

                    // Open the file chooser.  Currently only one `startActivityForResult` exists in this activity, so the request code, used to differentiate them, is simply `0`.
                    startActivityForResult(fileChooserIntent, 0);
                }
                return true;
            }
        });

        // Register `mainWebView` for a context menu.  This is used to see link targets and download images.
        registerForContextMenu(mainWebView);

        // Allow the downloading of files.
        mainWebView.setDownloadListener((String url, String userAgent, String contentDisposition, String mimetype, long contentLength) -> {
            // Check if the download should be processed by an external app.
            if (downloadWithExternalApp) {  // Download with an external app.
                openUrlWithExternalApp(url);
            } else {  // Download with Android's download manager.
                // Check to see if the WRITE_EXTERNAL_STORAGE permission has already been granted.
                if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_DENIED) {  // The storage permission has not been granted.
                    // The WRITE_EXTERNAL_STORAGE permission needs to be requested.

                    // Store the variables for future use by `onRequestPermissionsResult()`.
                    downloadUrl = url;
                    downloadContentDisposition = contentDisposition;
                    downloadContentLength = contentLength;

                    // Show a dialog if the user has previously denied the permission.
                    if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {  // Show a dialog explaining the request first.
                        // Instantiate the download location permission alert dialog and set the download type to DOWNLOAD_FILE.
                        DialogFragment downloadLocationPermissionDialogFragment = DownloadLocationPermissionDialog.downloadType(DownloadLocationPermissionDialog.DOWNLOAD_FILE);

                        // Show the download location permission alert dialog.  The permission will be requested when the the dialog is closed.
                        downloadLocationPermissionDialogFragment.show(fragmentManager, getString(R.string.download_location));
                    } else {  // Show the permission request directly.
                        // Request the permission.  The download dialog will be launched by `onRequestPermissionResult()`.
                        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, DOWNLOAD_FILE_REQUEST_CODE);
                    }
                } else {  // The storage permission has already been granted.
                    // Get a handle for the download file alert dialog.
                    DialogFragment downloadFileDialogFragment = DownloadFileDialog.fromUrl(url, contentDisposition, contentLength);

                    // Show the download file alert dialog.
                    downloadFileDialogFragment.show(fragmentManager, getString(R.string.download));
                }
            }
        });

        // Allow pinch to zoom.
        mainWebView.getSettings().setBuiltInZoomControls(true);

        // Hide zoom controls.
        mainWebView.getSettings().setDisplayZoomControls(false);

        // Don't allow mixed content (HTTP and HTTPS) on the same website.
        if (Build.VERSION.SDK_INT >= 21) {
            mainWebView.getSettings().setMixedContentMode(WebSettings.MIXED_CONTENT_NEVER_ALLOW);
        }

        // Set the WebView to use a wide viewport.  Otherwise, some web pages will be scrunched and some content will render outside the screen.
        mainWebView.getSettings().setUseWideViewPort(true);

        // Set the WebView to load in overview mode (zoomed out to the maximum width).
        mainWebView.getSettings().setLoadWithOverviewMode(true);

        // Explicitly disable geolocation.
        mainWebView.getSettings().setGeolocationEnabled(false);

        // Initialize cookieManager.
        cookieManager = CookieManager.getInstance();

        // Replace the header that `WebView` creates for `X-Requested-With` with a null value.  The default value is the application ID (com.stoutner.privacybrowser.standard).
        customHeaders.put("X-Requested-With", "");

        // Initialize the default preference values the first time the program is run.  `false` keeps this command from resetting any current preferences back to default.
        PreferenceManager.setDefaultValues(this, R.xml.preferences, false);

        // Get a handle for the `Runtime`.
        privacyBrowserRuntime = Runtime.getRuntime();

        // Store the application's private data directory.
        privateDataDirectoryString = getApplicationInfo().dataDir;
        // `dataDir` will vary, but will be something like `/data/user/0/com.stoutner.privacybrowser.standard`, which links to `/data/data/com.stoutner.privacybrowser.standard`.

        // Initialize `inFullScreenBrowsingMode`, which is always false at this point because Privacy Browser never starts in full screen browsing mode.
        inFullScreenBrowsingMode = false;

        // Initialize the privacy settings variables.
        javaScriptEnabled = false;
        firstPartyCookiesEnabled = false;
        thirdPartyCookiesEnabled = false;
        domStorageEnabled = false;
        saveFormDataEnabled = false;  // Form data can be removed once the minimum API >= 26.
        nightMode = false;

        // Store the default user agent.
        webViewDefaultUserAgent = mainWebView.getSettings().getUserAgentString();

        // Initialize the WebView title.
        webViewTitle = getString(R.string.no_title);

        // Initialize the favorite icon bitmap.  `ContextCompat` must be used until API >= 21.
        Drawable favoriteIconDrawable = ContextCompat.getDrawable(getApplicationContext(), R.drawable.world);
        BitmapDrawable favoriteIconBitmapDrawable = (BitmapDrawable) favoriteIconDrawable;
        assert favoriteIconBitmapDrawable != null;
        favoriteIconDefaultBitmap = favoriteIconBitmapDrawable.getBitmap();

        // If the favorite icon is null, load the default.
        if (favoriteIconBitmap == null) {
            favoriteIconBitmap = favoriteIconDefaultBitmap;
        }

        // Initialize the user agent array adapter and string array.
        userAgentNamesArray = ArrayAdapter.createFromResource(this, R.array.user_agent_names, R.layout.spinner_item);
        userAgentDataArray = resources.getStringArray(R.array.user_agent_data);

        // Apply the app settings from the shared preferences.
        applyAppSettings();

        // Instantiate the block list helper.
        BlockListHelper blockListHelper = new BlockListHelper();

        // Initialize the list of resource requests.
        resourceRequests = new ArrayList<>();

        // Parse the block lists.
        final ArrayList<List<String[]>> easyList = blockListHelper.parseBlockList(getAssets(), "blocklists/easylist.txt");
        final ArrayList<List<String[]>> easyPrivacy = blockListHelper.parseBlockList(getAssets(), "blocklists/easyprivacy.txt");
        final ArrayList<List<String[]>> fanboysAnnoyanceList = blockListHelper.parseBlockList(getAssets(), "blocklists/fanboy-annoyance.txt");
        final ArrayList<List<String[]>> fanboysSocialList = blockListHelper.parseBlockList(getAssets(), "blocklists/fanboy-social.txt");
        final ArrayList<List<String[]>> ultraPrivacy = blockListHelper.parseBlockList(getAssets(), "blocklists/ultraprivacy.txt");

        // Store the list versions.
        easyListVersion = easyList.get(0).get(0)[0];
        easyPrivacyVersion = easyPrivacy.get(0).get(0)[0];
        fanboysAnnoyanceVersion = fanboysAnnoyanceList.get(0).get(0)[0];
        fanboysSocialVersion = fanboysSocialList.get(0).get(0)[0];
        ultraPrivacyVersion = ultraPrivacy.get(0).get(0)[0];

        // Get a handle for the activity.  This is used to update the requests counter while the navigation menu is open.
        Activity activity = this;

        mainWebView.setWebViewClient(new WebViewClient() {
            // `shouldOverrideUrlLoading` makes this `WebView` the default handler for URLs inside the app, so that links are not kicked out to other apps.
            // The deprecated `shouldOverrideUrlLoading` must be used until API >= 24.
            @SuppressWarnings("deprecation")
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                if (url.startsWith("http")) {  // Load the URL in Privacy Browser.
                    // Reset the formatted URL string so the page will load correctly if blocking of third-party requests is enabled.
                    formattedUrlString = "";

                    // Apply the domain settings for the new URL.  `applyDomainSettings` doesn't do anything if the domain has not changed.
                    boolean userAgentChanged = applyDomainSettings(url, true, false);

                    // Check if the user agent has changed.
                    if (userAgentChanged) {
                        // Manually load the URL.  The changing of the user agent will cause WebView to reload the previous URL.
                        mainWebView.loadUrl(url, customHeaders);

                        // Returning true indicates that Privacy Browser is manually handling the loading of the URL.
                        return true;
                    } else {
                        // Returning false causes the current WebView to handle the URL and prevents it from adding redirects to the history list.
                        return false;
                    }
                } else if (url.startsWith("mailto:")) {  // Load the email address in an external email program.
                    // Use `ACTION_SENDTO` instead of `ACTION_SEND` so that only email programs are launched.
                    Intent emailIntent = new Intent(Intent.ACTION_SENDTO);

                    // Parse the url and set it as the data for the intent.
                    emailIntent.setData(Uri.parse(url));

                    // Open the email program in a new task instead of as part of Privacy Browser.
                    emailIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

                    // Make it so.
                    startActivity(emailIntent);

                    // Returning true indicates Privacy Browser is handling the URL by creating an intent.
                    return true;
                } else if (url.startsWith("tel:")) {  // Load the phone number in the dialer.
                    // Open the dialer and load the phone number, but wait for the user to place the call.
                    Intent dialIntent = new Intent(Intent.ACTION_DIAL);

                    // Add the phone number to the intent.
                    dialIntent.setData(Uri.parse(url));

                    // Open the dialer in a new task instead of as part of Privacy Browser.
                    dialIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

                    // Make it so.
                    startActivity(dialIntent);

                    // Returning true indicates Privacy Browser is handling the URL by creating an intent.
                    return true;
                } else {  // Load a system chooser to select an app that can handle the URL.
                    // Open an app that can handle the URL.
                    Intent genericIntent = new Intent(Intent.ACTION_VIEW);

                    // Add the URL to the intent.
                    genericIntent.setData(Uri.parse(url));

                    // List all apps that can handle the URL instead of just opening the first one.
                    genericIntent.addCategory(Intent.CATEGORY_BROWSABLE);

                    // Open the app in a new task instead of as part of Privacy Browser.
                    genericIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

                    // Start the app or display a snackbar if no app is available to handle the URL.
                    try {
                        startActivity(genericIntent);
                    } catch (ActivityNotFoundException exception) {
                        Snackbar.make(mainWebView, getString(R.string.unrecognized_url) + "  " + url, Snackbar.LENGTH_SHORT).show();
                    }

                    // Returning true indicates Privacy Browser is handling the URL by creating an intent.
                    return true;
                }
            }

            // Check requests against the block lists.  The deprecated `shouldInterceptRequest()` must be used until minimum API >= 21.
            @SuppressWarnings("deprecation")
            @Override
            public WebResourceResponse shouldInterceptRequest(WebView view, String url){
                // Create an empty web resource response to be used if the resource request is blocked.
                WebResourceResponse emptyWebResourceResponse = new WebResourceResponse("text/plain", "utf8", new ByteArrayInputStream("".getBytes()));

                // Reset the whitelist results tracker.
                whiteListResultStringArray = null;

                // Initialize the third party request tracker.
                boolean isThirdPartyRequest = false;

                // Initialize the current domain string.
                String currentDomain = "";

                // Nobody is happy when comparing null strings.
                if (!(formattedUrlString == null) && !(url == null)) {
                    // Get the domain strings to URIs.
                    Uri currentDomainUri = Uri.parse(formattedUrlString);
                    Uri requestDomainUri = Uri.parse(url);

                    // Get the domain host names.
                    String currentBaseDomain = currentDomainUri.getHost();
                    String requestBaseDomain = requestDomainUri.getHost();

                    // Update the current domain variable.
                    currentDomain = currentBaseDomain;

                    // Only compare the current base domain and the request base domain if neither is null.
                    if (!(currentBaseDomain == null) && !(requestBaseDomain == null)) {
                        // Determine the current base domain.
                        while (currentBaseDomain.indexOf(".", currentBaseDomain.indexOf(".") + 1) > 0) {  // There is at least one subdomain.
                            // Remove the first subdomain.
                            currentBaseDomain = currentBaseDomain.substring(currentBaseDomain.indexOf(".") + 1);
                        }

                        // Determine the request base domain.
                        while (requestBaseDomain.indexOf(".", requestBaseDomain.indexOf(".") + 1) > 0) {  // There is at least one subdomain.
                            // Remove the first subdomain.
                            requestBaseDomain = requestBaseDomain.substring(requestBaseDomain.indexOf(".") + 1);
                        }

                        // Update the third party request tracker.
                        isThirdPartyRequest = !currentBaseDomain.equals(requestBaseDomain);
                    }
                }

                // Block third-party requests if enabled.
                if (isThirdPartyRequest && blockAllThirdPartyRequests) {
                    // Increment the blocked requests counters.
                    blockedRequests++;
                    thirdPartyBlockedRequests++;

                    // Update the titles of the blocklist menu items.  This must be run from the UI thread.
                    activity.runOnUiThread(() -> {
                        navigationRequestsMenuItem.setTitle(getString(R.string.requests) + " - " + blockedRequests);
                        blocklistsMenuItem.setTitle(getString(R.string.requests) + " - " + blockedRequests);
                        blockAllThirdPartyRequestsMenuItem.setTitle(thirdPartyBlockedRequests + " - " + getString(R.string.block_all_third_party_requests));
                    });

                    // Add the request to the log.
                    resourceRequests.add(new String[]{String.valueOf(REQUEST_THIRD_PARTY), url});

                    // Return an empty web resource response.
                    return emptyWebResourceResponse;
                }

                // Check UltraPrivacy if it is enabled.
                if (ultraPrivacyEnabled) {
                    if (blockListHelper.isBlocked(currentDomain, url, isThirdPartyRequest, ultraPrivacy)) {
                        // Increment the blocked requests counters.
                        blockedRequests++;
                        ultraPrivacyBlockedRequests++;

                        // Update the titles of the blocklist menu items.  This must be run from the UI thread.
                        activity.runOnUiThread(() -> {
                            navigationRequestsMenuItem.setTitle(getString(R.string.requests) + " - " + blockedRequests);
                            blocklistsMenuItem.setTitle(getString(R.string.requests) + " - " + blockedRequests);
                            ultraPrivacyMenuItem.setTitle(ultraPrivacyBlockedRequests + " - " + getString(R.string.ultraprivacy));
                        });

                        // The resource request was blocked.  Return an empty web resource response.
                        return emptyWebResourceResponse;
                    }

                    // If the whitelist result is not null, the request has been allowed by UltraPrivacy.
                    if (whiteListResultStringArray != null) {
                        // Add a whitelist entry to the resource requests array.
                        resourceRequests.add(whiteListResultStringArray);

                        // The resource request has been allowed by UltraPrivacy.  `return null` loads the requested resource.
                        return null;
                    }
                }

                // Check EasyList if it is enabled.
                if (easyListEnabled) {
                    if (blockListHelper.isBlocked(currentDomain, url, isThirdPartyRequest, easyList)) {
                        // Increment the blocked requests counters.
                        blockedRequests++;
                        easyListBlockedRequests++;

                        // Update the titles of the blocklist menu items.  This must be run from the UI thread.
                        activity.runOnUiThread(() -> {
                            navigationRequestsMenuItem.setTitle(getString(R.string.requests) + " - " + blockedRequests);
                            blocklistsMenuItem.setTitle(getString(R.string.requests) + " - " + blockedRequests);
                            easyListMenuItem.setTitle(easyListBlockedRequests + " - " + getString(R.string.easylist));
                        });

                        // Reset the whitelist results tracker (because otherwise it will sometimes add results to the list due to a race condition).
                        whiteListResultStringArray = null;

                        // The resource request was blocked.  Return an empty web resource response.
                        return emptyWebResourceResponse;
                    }
                }

                // Check EasyPrivacy if it is enabled.
                if (easyPrivacyEnabled) {
                    if (blockListHelper.isBlocked(currentDomain, url, isThirdPartyRequest, easyPrivacy)) {
                        // Increment the blocked requests counters.
                        blockedRequests++;
                        easyPrivacyBlockedRequests++;

                        // Update the titles of the blocklist menu items.  This must be run from the UI thread.
                        activity.runOnUiThread(() -> {
                            navigationRequestsMenuItem.setTitle(getString(R.string.requests) + " - " + blockedRequests);
                            blocklistsMenuItem.setTitle(getString(R.string.requests) + " - " + blockedRequests);
                            easyPrivacyMenuItem.setTitle(easyPrivacyBlockedRequests + " - " + getString(R.string.easyprivacy));
                        });

                        // Reset the whitelist results tracker (because otherwise it will sometimes add results to the list due to a race condition).
                        whiteListResultStringArray = null;

                        // The resource request was blocked.  Return an empty web resource response.
                        return emptyWebResourceResponse;
                    }
                }

                // Check Fanboy’s Annoyance List if it is enabled.
                if (fanboysAnnoyanceListEnabled) {
                    if (blockListHelper.isBlocked(currentDomain, url, isThirdPartyRequest, fanboysAnnoyanceList)) {
                        // Increment the blocked requests counters.
                        blockedRequests++;
                        fanboysAnnoyanceListBlockedRequests++;

                        // Update the titles of the blocklist menu items.  This must be run from the UI thread.
                        activity.runOnUiThread(() -> {
                            navigationRequestsMenuItem.setTitle(getString(R.string.requests) + " - " + blockedRequests);
                            blocklistsMenuItem.setTitle(getString(R.string.requests) + " - " + blockedRequests);
                            fanboysAnnoyanceListMenuItem.setTitle(fanboysAnnoyanceListBlockedRequests + " - " + getString(R.string.fanboys_annoyance_list));
                        });

                        // Reset the whitelist results tracker (because otherwise it will sometimes add results to the list due to a race condition).
                        whiteListResultStringArray = null;

                        // The resource request was blocked.  Return an empty web resource response.
                        return emptyWebResourceResponse;
                    }
                } else if (fanboysSocialBlockingListEnabled){  // Only check Fanboy’s Social Blocking List if Fanboy’s Annoyance List is disabled.
                    if (blockListHelper.isBlocked(currentDomain, url, isThirdPartyRequest, fanboysSocialList)) {
                        // Increment the blocked requests counters.
                        blockedRequests++;
                        fanboysSocialBlockingListBlockedRequests++;

                        // Update the titles of the blocklist menu items.  This must be run from the UI thread.
                        activity.runOnUiThread(() -> {
                            navigationRequestsMenuItem.setTitle(getString(R.string.requests) + " - " + blockedRequests);
                            blocklistsMenuItem.setTitle(getString(R.string.requests) + " - " + blockedRequests);
                            fanboysSocialBlockingListMenuItem.setTitle(fanboysSocialBlockingListBlockedRequests + " - " + getString(R.string.fanboys_social_blocking_list));
                        });

                        // Reset the whitelist results tracker (because otherwise it will sometimes add results to the list due to a race condition).
                        whiteListResultStringArray = null;

                        // The resource request was blocked.  Return an empty web resource response.
                        return emptyWebResourceResponse;
                    }
                }

                // Add the request to the log because it hasn't been processed by any of the previous checks.
                if (whiteListResultStringArray != null ) {  // The request was processed by a whitelist.
                    resourceRequests.add(whiteListResultStringArray);
                } else {  // The request didn't match any blocklist entry.  Log it as a default request.
                    resourceRequests.add(new String[]{String.valueOf(REQUEST_DEFAULT), url});
                }

                // The resource request has not been blocked.  `return null` loads the requested resource.
                return null;
            }

            // Handle HTTP authentication requests.
            @Override
            public void onReceivedHttpAuthRequest(WebView view, HttpAuthHandler handler, String host, String realm) {
                // Store `handler` so it can be accessed from `onHttpAuthenticationCancel()` and `onHttpAuthenticationProceed()`.
                httpAuthHandler = handler;

                // Display the HTTP authentication dialog.
                DialogFragment httpAuthenticationDialogFragment = HttpAuthenticationDialog.displayDialog(host, realm);
                httpAuthenticationDialogFragment.show(fragmentManager, getString(R.string.http_authentication));
            }

            // Update the URL in urlTextBox when the page starts to load.
            @Override
            public void onPageStarted(WebView view, String url, Bitmap favicon) {
                // Set `urlIsLoading` to `true`, so that redirects while loading do not trigger changes in the user agent, which forces another reload of the existing page.
                // This is also used to determine when to check for pinned mismatches.
                urlIsLoading = true;

                // Reset the list of host IP addresses.
                currentHostIpAddresses = "";

                // Reset the list of resource requests.
                resourceRequests.clear();

                // Initialize the counters for requests blocked by each blocklist.
                blockedRequests = 0;
                easyListBlockedRequests = 0;
                easyPrivacyBlockedRequests = 0;
                fanboysAnnoyanceListBlockedRequests = 0;
                fanboysSocialBlockingListBlockedRequests = 0;
                ultraPrivacyBlockedRequests = 0;
                thirdPartyBlockedRequests = 0;

                // If night mode is enabled, hide `mainWebView` until after the night mode CSS is applied.
                if (nightMode) {
                    mainWebView.setVisibility(View.INVISIBLE);
                }

                // Hide the keyboard.  `0` indicates no additional flags.
                inputMethodManager.hideSoftInputFromWindow(mainWebView.getWindowToken(), 0);

                // Check to see if Privacy Browser is waiting on Orbot.
                if (!waitingForOrbot) {  // Process the URL.
                    // The formatted URL string must be updated at the beginning of the load, so that if the user toggles JavaScript during the load the new website is reloaded.
                    formattedUrlString = url;

                    // Display the formatted URL text.
                    urlTextBox.setText(formattedUrlString);

                    // Apply text highlighting to `urlTextBox`.
                    highlightUrlText();

                    // Get a URI for the current URL.
                    Uri currentUri = Uri.parse(formattedUrlString);

                    // Get the IP addresses for the host.
                    new GetHostIpAddresses(activity).execute(currentUri.getHost());

                    // Apply any custom domain settings if the URL was loaded by navigating history.
                    if (navigatingHistory) {
                        // Apply the domain settings.
                        boolean userAgentChanged = applyDomainSettings(url, true, false);

                        // Reset `navigatingHistory`.
                        navigatingHistory = false;

                        // Manually load the URL if the user agent has changed, which will have caused the previous URL to be reloaded.
                        if (userAgentChanged) {
                            loadUrl(formattedUrlString);
                        }
                    }

                    // Replace Refresh with Stop if the menu item has been created.  (The WebView typically begins loading before the menu items are instantiated.)
                    if (refreshMenuItem != null) {
                        // Set the title.
                        refreshMenuItem.setTitle(R.string.stop);

                        // If the icon is displayed in the AppBar, set it according to the theme.
                        if (displayAdditionalAppBarIcons) {
                            if (darkTheme) {
                                refreshMenuItem.setIcon(R.drawable.close_dark);
                            } else {
                                refreshMenuItem.setIcon(R.drawable.close_light);
                            }
                        }
                    }
                }
            }

            // It is necessary to update `formattedUrlString` and `urlTextBox` after the page finishes loading because the final URL can change during load.
            @Override
            public void onPageFinished(WebView view, String url) {
                // Reset the wide view port if it has been turned off by the waiting for Orbot message.
                if (!waitingForOrbot) {
                    // Only use a wide view port if the URL starts with `http`, not for `file://` and `content://`.
                    mainWebView.getSettings().setUseWideViewPort(url.startsWith("http"));
                }

                // Flush any cookies to persistent storage.  `CookieManager` has become very lazy about flushing cookies in recent versions.
                if (firstPartyCookiesEnabled && Build.VERSION.SDK_INT >= 21) {
                    cookieManager.flush();
                }

                // Update the Refresh menu item if it has been created.
                if (refreshMenuItem != null) {
                    // Reset the Refresh title.
                    refreshMenuItem.setTitle(R.string.refresh);

                    // If the icon is displayed in the AppBar, reset it according to the theme.
                    if (displayAdditionalAppBarIcons) {
                        if (darkTheme) {
                            refreshMenuItem.setIcon(R.drawable.refresh_enabled_dark);
                        } else {
                            refreshMenuItem.setIcon(R.drawable.refresh_enabled_light);
                        }
                    }
                }



                // Clear the cache and history if Incognito Mode is enabled.
                if (incognitoModeEnabled) {
                    // Clear the cache.  `true` includes disk files.
                    mainWebView.clearCache(true);

                    // Clear the back/forward history.
                    mainWebView.clearHistory();

                    // Manually delete cache folders.
                    try {
                        // Delete the main cache directory.
                        privacyBrowserRuntime.exec("rm -rf " + privateDataDirectoryString + "/cache");

                        // Delete the secondary `Service Worker` cache directory.
                        // A `String[]` must be used because the directory contains a space and `Runtime.exec` will not escape the string correctly otherwise.
                        privacyBrowserRuntime.exec(new String[] {"rm", "-rf", privateDataDirectoryString + "/app_webview/Service Worker/"});
                    } catch (IOException e) {
                        // Do nothing if an error is thrown.
                    }
                }

                // Update the URL text box and apply domain settings if not waiting on Orbot.
                if (!waitingForOrbot) {
                    // Check to see if `WebView` has set `url` to be `about:blank`.
                    if (url.equals("about:blank")) {  // `WebView` is blank, so `formattedUrlString` should be `""` and `urlTextBox` should display a hint.
                        // Set `formattedUrlString` to `""`.
                        formattedUrlString = "";

                        urlTextBox.setText(formattedUrlString);

                        // Request focus for `urlTextBox`.
                        urlTextBox.requestFocus();

                        // Display the keyboard.
                        inputMethodManager.showSoftInput(urlTextBox, 0);

                        // Apply the domain settings.  This clears any settings from the previous domain.
                        applyDomainSettings(formattedUrlString, true, false);
                    } else {  // `WebView` has loaded a webpage.
                        // Set the formatted URL string.  Getting the URL from the WebView instead of using the one provided by `onPageFinished` makes websites like YouTube function correctly.
                        formattedUrlString = mainWebView.getUrl();

                        // Only update the URL text box if the user is not typing in it.
                        if (!urlTextBox.hasFocus()) {
                            // Display the formatted URL text.
                            urlTextBox.setText(formattedUrlString);

                            // Apply text highlighting to `urlTextBox`.
                            highlightUrlText();
                        }
                    }

                    // Store the SSL certificate so it can be accessed from `ViewSslCertificateDialog` and `PinnedMismatchDialog`.
                    sslCertificate = mainWebView.getCertificate();

                    // Check the current website information against any pinned domain information if the current IP addresses have been loaded.
                    if (!gettingIpAddresses) {
                        checkPinnedMismatch();
                    }
                }

                // Reset `urlIsLoading`, which is used to prevent reloads on redirect if the user agent changes.  It is also used to determine when to check for pinned mismatches.
                urlIsLoading = false;
            }

            // Handle SSL Certificate errors.
            @Override
            public void onReceivedSslError(WebView view, SslErrorHandler handler, SslError error) {
                // Get the current website SSL certificate.
                SslCertificate currentWebsiteSslCertificate = error.getCertificate();

                // Extract the individual pieces of information from the current website SSL certificate.
                String currentWebsiteIssuedToCName = currentWebsiteSslCertificate.getIssuedTo().getCName();
                String currentWebsiteIssuedToOName = currentWebsiteSslCertificate.getIssuedTo().getOName();
                String currentWebsiteIssuedToUName = currentWebsiteSslCertificate.getIssuedTo().getUName();
                String currentWebsiteIssuedByCName = currentWebsiteSslCertificate.getIssuedBy().getCName();
                String currentWebsiteIssuedByOName = currentWebsiteSslCertificate.getIssuedBy().getOName();
                String currentWebsiteIssuedByUName = currentWebsiteSslCertificate.getIssuedBy().getUName();
                Date currentWebsiteSslStartDate = currentWebsiteSslCertificate.getValidNotBeforeDate();
                Date currentWebsiteSslEndDate = currentWebsiteSslCertificate.getValidNotAfterDate();

                // Proceed to the website if the current SSL website certificate matches the pinned domain certificate.
                if (pinnedSslCertificate &&
                        currentWebsiteIssuedToCName.equals(pinnedSslIssuedToCName) && currentWebsiteIssuedToOName.equals(pinnedSslIssuedToOName) &&
                        currentWebsiteIssuedToUName.equals(pinnedSslIssuedToUName) && currentWebsiteIssuedByCName.equals(pinnedSslIssuedByCName) &&
                        currentWebsiteIssuedByOName.equals(pinnedSslIssuedByOName) && currentWebsiteIssuedByUName.equals(pinnedSslIssuedByUName) &&
                        currentWebsiteSslStartDate.equals(pinnedSslStartDate) && currentWebsiteSslEndDate.equals(pinnedSslEndDate)) {

                    // An SSL certificate is pinned and matches the current domain certificate.  Proceed to the website without displaying an error.
                    handler.proceed();
                } else {  // Either there isn't a pinned SSL certificate or it doesn't match the current website certificate.
                    // Store `handler` so it can be accesses from `onSslErrorCancel()` and `onSslErrorProceed()`.
                    sslErrorHandler = handler;

                    // Display the SSL error `AlertDialog`.
                    DialogFragment sslCertificateErrorDialogFragment = SslCertificateErrorDialog.displayDialog(error);
                    sslCertificateErrorDialogFragment.show(fragmentManager, getString(R.string.ssl_certificate_error));
                }
            }
        });

        // Get the intent that started the app.
        Intent launchingIntent = getIntent();

        // Get the information from the intent.
        String launchingIntentAction = launchingIntent.getAction();
        Uri launchingIntentUriData = launchingIntent.getData();

        // If the intent action is a web search, perform the search.
        if ((launchingIntentAction != null) && launchingIntentAction.equals(Intent.ACTION_WEB_SEARCH)) {
            // Create an encoded URL string.
            String encodedUrlString;

            // Sanitize the search input and convert it to a search.
            try {
                encodedUrlString = URLEncoder.encode(launchingIntent.getStringExtra(SearchManager.QUERY), "UTF-8");
            } catch (UnsupportedEncodingException exception) {
                encodedUrlString = "";
            }

            // Add the base search URL.
            formattedUrlString = searchURL + encodedUrlString;
        } else if (launchingIntentUriData != null){  // Check to see if the intent contains a new URL.
            // Set the formatted URL string.
            formattedUrlString = launchingIntentUriData.toString();
        }

        // Load the website if not waiting for Orbot to connect.
        if (!waitingForOrbot) {
            loadUrl(formattedUrlString);
        }
    }

    @Override
    protected void onNewIntent(Intent intent) {
        // Sets the new intent as the activity intent, so that any future `getIntent()`s pick up this one instead of creating a new activity.
        setIntent(intent);

        // Get the information from the intent.
        String intentAction = intent.getAction();
        Uri intentUriData = intent.getData();

        // If the intent action is a web search, perform the search.
        if ((intentAction != null) && intentAction.equals(Intent.ACTION_WEB_SEARCH)) {
            // Create an encoded URL string.
            String encodedUrlString;

            // Sanitize the search input and convert it to a search.
            try {
                encodedUrlString = URLEncoder.encode(intent.getStringExtra(SearchManager.QUERY), "UTF-8");
            } catch (UnsupportedEncodingException exception) {
                encodedUrlString = "";
            }

            // Add the base search URL.
            formattedUrlString = searchURL + encodedUrlString;
        } else if (intentUriData != null){  // Check to see if the intent contains a new URL.
            // Set the formatted URL string.
            formattedUrlString = intentUriData.toString();
        }

        // Load the URL.
        loadUrl(formattedUrlString);

        // Get a handle for the drawer layout.
        DrawerLayout drawerLayout = findViewById(R.id.drawerlayout);

        // Close the navigation drawer if it is open.
        if (drawerLayout.isDrawerVisible(GravityCompat.START)) {
            drawerLayout.closeDrawer(GravityCompat.START);
        }

        // Close the bookmarks drawer if it is open.
        if (drawerLayout.isDrawerVisible(GravityCompat.END)) {
            drawerLayout.closeDrawer(GravityCompat.END);
        }

        // Clear the keyboard if displayed and remove the focus on the urlTextBar if it has it.
        mainWebView.requestFocus();
    }

    @Override
    public void onRestart() {
        // Run the default commands.
        super.onRestart();

        // Make sure Orbot is running if Privacy Browser is proxying through Orbot.
        if (proxyThroughOrbot) {
            // Request Orbot to start.  If Orbot is already running no hard will be caused by this request.
            Intent orbotIntent = new Intent("org.torproject.android.intent.action.START");

            // Send the intent to the Orbot package.
            orbotIntent.setPackage("org.torproject.android");

            // Make it so.
            sendBroadcast(orbotIntent);
        }

        // Apply the app settings if returning from the Settings activity..
        if (reapplyAppSettingsOnRestart) {
            // Apply the app settings.
            applyAppSettings();

            // Reload the webpage if displaying of images has been disabled in the Settings activity.
            if (reloadOnRestart) {
                // Reload `mainWebView`.
                mainWebView.reload();

                // Reset `reloadOnRestartBoolean`.
                reloadOnRestart = false;
            }

            // Reset the return from settings flag.
            reapplyAppSettingsOnRestart = false;
        }

        // Apply the domain settings if returning from the Domains activity.
        if (reapplyDomainSettingsOnRestart) {
            // Reapply the domain settings.
            applyDomainSettings(formattedUrlString, false, true);

            // Reset `reapplyDomainSettingsOnRestart`.
            reapplyDomainSettingsOnRestart = false;
        }

        // Load the URL on restart to apply changes to night mode.
        if (loadUrlOnRestart) {
            // Load the current `formattedUrlString`.
            loadUrl(formattedUrlString);

            // Reset `loadUrlOnRestart.
            loadUrlOnRestart = false;
        }

        // Update the bookmarks drawer if returning from the Bookmarks activity.
        if (restartFromBookmarksActivity) {
            // Get a handle for the drawer layout.
            DrawerLayout drawerLayout = findViewById(R.id.drawerlayout);

            // Close the bookmarks drawer.
            drawerLayout.closeDrawer(GravityCompat.END);

            // Reload the bookmarks drawer.
            loadBookmarksFolder();

            // Reset `restartFromBookmarksActivity`.
            restartFromBookmarksActivity = false;
        }

        // Update the privacy icon.  `true` runs `invalidateOptionsMenu` as the last step.  This can be important if the screen was rotated.
        updatePrivacyIcons(true);
    }

    // `onResume()` runs after `onStart()`, which runs after `onCreate()` and `onRestart()`.
    @Override
    public void onResume() {
        // Run the default commands.
        super.onResume();

        // Resume JavaScript (if enabled).
        mainWebView.resumeTimers();

        // Resume `mainWebView`.
        mainWebView.onResume();

        // Resume the adView for the free flavor.
        if (BuildConfig.FLAVOR.contentEquals("free")) {
            // Resume the ad.
            AdHelper.resumeAd(findViewById(R.id.adview));
        }

        // Display a message to the user if waiting for Orbot.
        if (waitingForOrbot && !orbotStatus.equals("ON")) {
            // Disable the wide view port so that the waiting for Orbot text is displayed correctly.
            mainWebView.getSettings().setUseWideViewPort(false);

            // Load a waiting page.  `null` specifies no encoding, which defaults to ASCII.
            mainWebView.loadData(waitingForOrbotHtmlString, "text/html", null);
        }

        if (displayingFullScreenVideo) {
            // Get handles for the layouts that need to be modified.
            DrawerLayout drawerLayout = findViewById(R.id.drawerlayout);
            CoordinatorLayout coordinatorLayout = findViewById(R.id.coordinatorlayout);

            // Remove the translucent overlays.
            getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);

            // Remove the translucent status bar overlay on the `Drawer Layout`, which is special and needs its own command.
            drawerLayout.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);

            /* SYSTEM_UI_FLAG_FULLSCREEN hides the status bar at the top of the screen.
             * SYSTEM_UI_FLAG_HIDE_NAVIGATION hides the navigation bar on the bottom or right of the screen.
             * SYSTEM_UI_FLAG_IMMERSIVE_STICKY makes the status and navigation bars translucent and automatically re-hides them after they are shown.
             */
            coordinatorLayout.setSystemUiVisibility(View.SYSTEM_UI_FLAG_FULLSCREEN | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
        }
    }

    @Override
    public void onPause() {
        // Run the default commands.
        super.onPause();

        // Pause `mainWebView`.
        mainWebView.onPause();

        // Stop all JavaScript.
        mainWebView.pauseTimers();

        // Pause the ad or it will continue to consume resources in the background on the free flavor.
        if (BuildConfig.FLAVOR.contentEquals("free")) {
            // Pause the ad.
            AdHelper.pauseAd(findViewById(R.id.adview));
        }
    }

    @Override
    public void onDestroy() {
        // Unregister the Orbot status broadcast receiver.
        this.unregisterReceiver(orbotStatusBroadcastReceiver);

        // Close the bookmarks cursor and database.
        bookmarksCursor.close();
        bookmarksDatabaseHelper.close();

        // Run the default commands.
        super.onDestroy();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu.  This adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.webview_options_menu, menu);

        // Set mainMenu so it can be used by `onOptionsItemSelected()` and `updatePrivacyIcons`.
        mainMenu = menu;

        // Set the initial status of the privacy icons.  `false` does not call `invalidateOptionsMenu` as the last step.
        updatePrivacyIcons(false);

        // Get handles for the menu items.
        MenuItem toggleFirstPartyCookiesMenuItem = menu.findItem(R.id.toggle_first_party_cookies);
        MenuItem toggleThirdPartyCookiesMenuItem = menu.findItem(R.id.toggle_third_party_cookies);
        MenuItem toggleDomStorageMenuItem = menu.findItem(R.id.toggle_dom_storage);
        MenuItem toggleSaveFormDataMenuItem = menu.findItem(R.id.toggle_save_form_data);  // Form data can be removed once the minimum API >= 26.
        MenuItem clearFormDataMenuItem = menu.findItem(R.id.clear_form_data);  // Form data can be removed once the minimum API >= 26.
        refreshMenuItem = menu.findItem(R.id.refresh);
        blocklistsMenuItem = menu.findItem(R.id.blocklists);
        easyListMenuItem = menu.findItem(R.id.easylist);
        easyPrivacyMenuItem = menu.findItem(R.id.easyprivacy);
        fanboysAnnoyanceListMenuItem = menu.findItem(R.id.fanboys_annoyance_list);
        fanboysSocialBlockingListMenuItem = menu.findItem(R.id.fanboys_social_blocking_list);
        ultraPrivacyMenuItem = menu.findItem(R.id.ultraprivacy);
        blockAllThirdPartyRequestsMenuItem = menu.findItem(R.id.block_all_third_party_requests);
        MenuItem adConsentMenuItem = menu.findItem(R.id.ad_consent);

        // Only display third-party cookies if API >= 21
        toggleThirdPartyCookiesMenuItem.setVisible(Build.VERSION.SDK_INT >= 21);

        // Only display the form data menu items if the API < 26.
        toggleSaveFormDataMenuItem.setVisible(Build.VERSION.SDK_INT < 26);
        clearFormDataMenuItem.setVisible(Build.VERSION.SDK_INT < 26);

        // Only show Ad Consent if this is the free flavor.
        adConsentMenuItem.setVisible(BuildConfig.FLAVOR.contentEquals("free"));

        // Get the shared preference values.
        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);

        // Get the status of the additional AppBar icons.
        displayAdditionalAppBarIcons = sharedPreferences.getBoolean("display_additional_app_bar_icons", false);

        // Set the status of the additional app bar icons.  Setting the refresh menu item to `SHOW_AS_ACTION_ALWAYS` makes it appear even on small devices like phones.
        if (displayAdditionalAppBarIcons) {
            toggleFirstPartyCookiesMenuItem.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);
            toggleDomStorageMenuItem.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);
            refreshMenuItem.setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);
        } else { //Do not display the additional icons.
            toggleFirstPartyCookiesMenuItem.setShowAsAction(MenuItem.SHOW_AS_ACTION_NEVER);
            toggleDomStorageMenuItem.setShowAsAction(MenuItem.SHOW_AS_ACTION_NEVER);
            refreshMenuItem.setShowAsAction(MenuItem.SHOW_AS_ACTION_NEVER);
        }

        // Replace Refresh with Stop if a URL is already loading.
        if (urlIsLoading) {
            // Set the title.
            refreshMenuItem.setTitle(R.string.stop);

            // If the icon is displayed in the AppBar, set it according to the theme.
            if (displayAdditionalAppBarIcons) {
                if (darkTheme) {
                    refreshMenuItem.setIcon(R.drawable.close_dark);
                } else {
                    refreshMenuItem.setIcon(R.drawable.close_light);
                }
            }
        }

        return true;
    }

    @Override
    public boolean onPrepareOptionsMenu(Menu menu) {
        // Get a handle for the swipe refresh layout.
        SwipeRefreshLayout swipeRefreshLayout = findViewById(R.id.swiperefreshlayout);

        // Get handles for the menu items.
        MenuItem addOrEditDomain = menu.findItem(R.id.add_or_edit_domain);
        MenuItem toggleFirstPartyCookiesMenuItem = menu.findItem(R.id.toggle_first_party_cookies);
        MenuItem toggleThirdPartyCookiesMenuItem = menu.findItem(R.id.toggle_third_party_cookies);
        MenuItem toggleDomStorageMenuItem = menu.findItem(R.id.toggle_dom_storage);
        MenuItem toggleSaveFormDataMenuItem = menu.findItem(R.id.toggle_save_form_data);  // Form data can be removed once the minimum API >= 26.
        MenuItem clearDataMenuItem = menu.findItem(R.id.clear_data);
        MenuItem clearCookiesMenuItem = menu.findItem(R.id.clear_cookies);
        MenuItem clearDOMStorageMenuItem = menu.findItem(R.id.clear_dom_storage);
        MenuItem clearFormDataMenuItem = menu.findItem(R.id.clear_form_data);  // Form data can be removed once the minimum API >= 26.
        MenuItem fontSizeMenuItem = menu.findItem(R.id.font_size);
        MenuItem swipeToRefreshMenuItem = menu.findItem(R.id.swipe_to_refresh);
        MenuItem displayImagesMenuItem = menu.findItem(R.id.display_images);
        MenuItem nightModeMenuItem = menu.findItem(R.id.night_mode);
        MenuItem proxyThroughOrbotMenuItem = menu.findItem(R.id.proxy_through_orbot);

        // Set the text for the domain menu item.
        if (domainSettingsApplied) {
            addOrEditDomain.setTitle(R.string.edit_domain_settings);
        } else {
            addOrEditDomain.setTitle(R.string.add_domain_settings);
        }

        // Set the status of the menu item checkboxes.
        toggleFirstPartyCookiesMenuItem.setChecked(firstPartyCookiesEnabled);
        toggleThirdPartyCookiesMenuItem.setChecked(thirdPartyCookiesEnabled);
        toggleDomStorageMenuItem.setChecked(domStorageEnabled);
        toggleSaveFormDataMenuItem.setChecked(saveFormDataEnabled);  // Form data can be removed once the minimum API >= 26.
        easyListMenuItem.setChecked(easyListEnabled);
        easyPrivacyMenuItem.setChecked(easyPrivacyEnabled);
        fanboysAnnoyanceListMenuItem.setChecked(fanboysAnnoyanceListEnabled);
        fanboysSocialBlockingListMenuItem.setChecked(fanboysSocialBlockingListEnabled);
        ultraPrivacyMenuItem.setChecked(ultraPrivacyEnabled);
        blockAllThirdPartyRequestsMenuItem.setChecked(blockAllThirdPartyRequests);
        swipeToRefreshMenuItem.setChecked(swipeRefreshLayout.isEnabled());
        displayImagesMenuItem.setChecked(mainWebView.getSettings().getLoadsImagesAutomatically());
        nightModeMenuItem.setChecked(nightMode);
        proxyThroughOrbotMenuItem.setChecked(proxyThroughOrbot);

        // Enable third-party cookies if first-party cookies are enabled.
        toggleThirdPartyCookiesMenuItem.setEnabled(firstPartyCookiesEnabled);

        // Enable DOM Storage if JavaScript is enabled.
        toggleDomStorageMenuItem.setEnabled(javaScriptEnabled);

        // Enable Clear Cookies if there are any.
        clearCookiesMenuItem.setEnabled(cookieManager.hasCookies());

        // Get a count of the number of files in the Local Storage directory.
        File localStorageDirectory = new File (privateDataDirectoryString + "/app_webview/Local Storage/");
        int localStorageDirectoryNumberOfFiles = 0;
        if (localStorageDirectory.exists()) {
            localStorageDirectoryNumberOfFiles = localStorageDirectory.list().length;
        }

        // Get a count of the number of files in the IndexedDB directory.
        File indexedDBDirectory = new File (privateDataDirectoryString + "/app_webview/IndexedDB");
        int indexedDBDirectoryNumberOfFiles = 0;
        if (indexedDBDirectory.exists()) {
            indexedDBDirectoryNumberOfFiles = indexedDBDirectory.list().length;
        }

        // Enable Clear DOM Storage if there is any.
        clearDOMStorageMenuItem.setEnabled(localStorageDirectoryNumberOfFiles > 0 || indexedDBDirectoryNumberOfFiles > 0);

        // Enable Clear Form Data is there is any.  This can be removed once the minimum API >= 26.
        if (Build.VERSION.SDK_INT < 26) {
            WebViewDatabase mainWebViewDatabase = WebViewDatabase.getInstance(this);
            clearFormDataMenuItem.setEnabled(mainWebViewDatabase.hasFormData());
        } else {
            // Disable clear form data because it is not supported on current version of Android.
            clearFormDataMenuItem.setEnabled(false);
        }

        // Enable Clear Data if any of the submenu items are enabled.
        clearDataMenuItem.setEnabled(clearCookiesMenuItem.isEnabled() || clearDOMStorageMenuItem.isEnabled() || clearFormDataMenuItem.isEnabled());

        // Disable Fanboy's Social Blocking List if Fanboy's Annoyance List is checked.
        fanboysSocialBlockingListMenuItem.setEnabled(!fanboysAnnoyanceListEnabled);

        // Initialize the display names for the blocklists with the number of blocked requests.
        blocklistsMenuItem.setTitle(getString(R.string.blocklists) + " - " + blockedRequests);
        easyListMenuItem.setTitle(easyListBlockedRequests + " - " + getString(R.string.easylist));
        easyPrivacyMenuItem.setTitle(easyPrivacyBlockedRequests + " - " + getString(R.string.easyprivacy));
        fanboysAnnoyanceListMenuItem.setTitle(fanboysAnnoyanceListBlockedRequests + " - " + getString(R.string.fanboys_annoyance_list));
        fanboysSocialBlockingListMenuItem.setTitle(fanboysSocialBlockingListBlockedRequests + " - " + getString(R.string.fanboys_social_blocking_list));
        ultraPrivacyMenuItem.setTitle(ultraPrivacyBlockedRequests + " - " + getString(R.string.ultraprivacy));
        blockAllThirdPartyRequestsMenuItem.setTitle(thirdPartyBlockedRequests + " - " + getString(R.string.block_all_third_party_requests));

        // Get the current user agent.
        String currentUserAgent = mainWebView.getSettings().getUserAgentString();

        // Select the current user agent menu item.  A switch statement cannot be used because the user agents are not compile time constants.
        if (currentUserAgent.equals(getResources().getStringArray(R.array.user_agent_data)[0])) {  // Privacy Browser.
            menu.findItem(R.id.user_agent_privacy_browser).setChecked(true);
        } else if (currentUserAgent.equals(webViewDefaultUserAgent)) {  // WebView Default.
            menu.findItem(R.id.user_agent_webview_default).setChecked(true);
        } else if (currentUserAgent.equals(getResources().getStringArray(R.array.user_agent_data)[2])) {  // Firefox on Android.
            menu.findItem(R.id.user_agent_firefox_on_android).setChecked(true);
        } else if (currentUserAgent.equals(getResources().getStringArray(R.array.user_agent_data)[3])) {  // Chrome on Android.
            menu.findItem(R.id.user_agent_chrome_on_android).setChecked(true);
        } else if (currentUserAgent.equals(getResources().getStringArray(R.array.user_agent_data)[4])) {  // Safari on iOS.
            menu.findItem(R.id.user_agent_safari_on_ios).setChecked(true);
        } else if (currentUserAgent.equals(getResources().getStringArray(R.array.user_agent_data)[5])) {  // Firefox on Linux.
            menu.findItem(R.id.user_agent_firefox_on_linux).setChecked(true);
        } else if (currentUserAgent.equals(getResources().getStringArray(R.array.user_agent_data)[6])) {  // Chromium on Linux.
            menu.findItem(R.id.user_agent_chromium_on_linux).setChecked(true);
        } else if (currentUserAgent.equals(getResources().getStringArray(R.array.user_agent_data)[7])) {  // Firefox on Windows.
            menu.findItem(R.id.user_agent_firefox_on_windows).setChecked(true);
        } else if (currentUserAgent.equals(getResources().getStringArray(R.array.user_agent_data)[8])) {  // Chrome on Windows.
            menu.findItem(R.id.user_agent_chrome_on_windows).setChecked(true);
        } else if (currentUserAgent.equals(getResources().getStringArray(R.array.user_agent_data)[9])) {  // Edge on Windows.
            menu.findItem(R.id.user_agent_edge_on_windows).setChecked(true);
        } else if (currentUserAgent.equals(getResources().getStringArray(R.array.user_agent_data)[10])) {  // Internet Explorer on Windows.
            menu.findItem(R.id.user_agent_internet_explorer_on_windows).setChecked(true);
        } else if (currentUserAgent.equals(getResources().getStringArray(R.array.user_agent_data)[11])) {  // Safari on macOS.
            menu.findItem(R.id.user_agent_safari_on_macos).setChecked(true);
        } else {  // Custom user agent.
            menu.findItem(R.id.user_agent_custom).setChecked(true);
        }

        // Initialize font size variables.
        int fontSize = mainWebView.getSettings().getTextZoom();
        String fontSizeTitle;
        MenuItem selectedFontSizeMenuItem;

        // Prepare the font size title and current size menu item.
        switch (fontSize) {
            case 25:
                fontSizeTitle = getString(R.string.font_size) + " - " + getString(R.string.twenty_five_percent);
                selectedFontSizeMenuItem = menu.findItem(R.id.font_size_twenty_five_percent);
                break;

            case 50:
                fontSizeTitle = getString(R.string.font_size) + " - " + getString(R.string.fifty_percent);
                selectedFontSizeMenuItem = menu.findItem(R.id.font_size_fifty_percent);
                break;

            case 75:
                fontSizeTitle = getString(R.string.font_size) + " - " + getString(R.string.seventy_five_percent);
                selectedFontSizeMenuItem = menu.findItem(R.id.font_size_seventy_five_percent);
                break;

            case 100:
                fontSizeTitle = getString(R.string.font_size) + " - " + getString(R.string.one_hundred_percent);
                selectedFontSizeMenuItem = menu.findItem(R.id.font_size_one_hundred_percent);
                break;

            case 125:
                fontSizeTitle = getString(R.string.font_size) + " - " + getString(R.string.one_hundred_twenty_five_percent);
                selectedFontSizeMenuItem = menu.findItem(R.id.font_size_one_hundred_twenty_five_percent);
                break;

            case 150:
                fontSizeTitle = getString(R.string.font_size) + " - " + getString(R.string.one_hundred_fifty_percent);
                selectedFontSizeMenuItem = menu.findItem(R.id.font_size_one_hundred_fifty_percent);
                break;

            case 175:
                fontSizeTitle = getString(R.string.font_size) + " - " + getString(R.string.one_hundred_seventy_five_percent);
                selectedFontSizeMenuItem = menu.findItem(R.id.font_size_one_hundred_seventy_five_percent);
                break;

            case 200:
                fontSizeTitle = getString(R.string.font_size) + " - " + getString(R.string.two_hundred_percent);
                selectedFontSizeMenuItem = menu.findItem(R.id.font_size_two_hundred_percent);
                break;

            default:
                fontSizeTitle = getString(R.string.font_size) + " - " + getString(R.string.one_hundred_percent);
                selectedFontSizeMenuItem = menu.findItem(R.id.font_size_one_hundred_percent);
                break;
        }

        // Set the font size title and select the current size menu item.
        fontSizeMenuItem.setTitle(fontSizeTitle);
        selectedFontSizeMenuItem.setChecked(true);

        // Run all the other default commands.
        super.onPrepareOptionsMenu(menu);

        // Display the menu.
        return true;
    }

    @Override
    // Remove Android Studio's warning about the dangers of using SetJavaScriptEnabled.
    @SuppressLint("SetJavaScriptEnabled")
    // removeAllCookies is deprecated, but it is required for API < 21.
    @SuppressWarnings("deprecation")
    public boolean onOptionsItemSelected(MenuItem menuItem) {
        // Get the selected menu item ID.
        int menuItemId = menuItem.getItemId();

        // Run the commands that correlate to the selected menu item.
        switch (menuItemId) {
            case R.id.toggle_javascript:
                // Switch the status of javaScriptEnabled.
                javaScriptEnabled = !javaScriptEnabled;

                // Apply the new JavaScript status.
                mainWebView.getSettings().setJavaScriptEnabled(javaScriptEnabled);

                // Update the privacy icon.  `true` runs `invalidateOptionsMenu` as the last step.
                updatePrivacyIcons(true);

                // Display a `Snackbar`.
                if (javaScriptEnabled) {  // JavaScrip is enabled.
                    Snackbar.make(findViewById(R.id.main_webview), R.string.javascript_enabled, Snackbar.LENGTH_SHORT).show();
                } else if (firstPartyCookiesEnabled) {  // JavaScript is disabled, but first-party cookies are enabled.
                    Snackbar.make(findViewById(R.id.main_webview), R.string.javascript_disabled, Snackbar.LENGTH_SHORT).show();
                } else {  // Privacy mode.
                    Snackbar.make(findViewById(R.id.main_webview), R.string.privacy_mode, Snackbar.LENGTH_SHORT).show();
                }

                // Reload the WebView.
                mainWebView.reload();
                return true;

            case R.id.add_or_edit_domain:
                if (domainSettingsApplied) {  // Edit the current domain settings.
                    // Reapply the domain settings on returning to `MainWebViewActivity`.
                    reapplyDomainSettingsOnRestart = true;
                    currentDomainName = "";

                    // Create an intent to launch the domains activity.
                    Intent domainsIntent = new Intent(this, DomainsActivity.class);

                    // Put extra information instructing the domains activity to directly load the current domain and close on back instead of returning to the domains list.
                    domainsIntent.putExtra("loadDomain", domainSettingsDatabaseId);
                    domainsIntent.putExtra("closeOnBack", true);

                    // Make it so.
                    startActivity(domainsIntent);
                } else {  // Add a new domain.
                    // Apply the new domain settings on returning to `MainWebViewActivity`.
                    reapplyDomainSettingsOnRestart = true;
                    currentDomainName = "";

                    // Get the current domain
                    Uri currentUri = Uri.parse(formattedUrlString);
                    String currentDomain = currentUri.getHost();

                    // Initialize the database handler.  The `0` specifies the database version, but that is ignored and set instead using a constant in `DomainsDatabaseHelper`.
                    DomainsDatabaseHelper domainsDatabaseHelper = new DomainsDatabaseHelper(this, null, null, 0);

                    // Create the domain and store the database ID.
                    int newDomainDatabaseId = domainsDatabaseHelper.addDomain(currentDomain);

                    // Create an intent to launch the domains activity.
                    Intent domainsIntent = new Intent(this, DomainsActivity.class);

                    // Put extra information instructing the domains activity to directly load the new domain and close on back instead of returning to the domains list.
                    domainsIntent.putExtra("loadDomain", newDomainDatabaseId);
                    domainsIntent.putExtra("closeOnBack", true);

                    // Make it so.
                    startActivity(domainsIntent);
                }
                return true;

            case R.id.toggle_first_party_cookies:
                // Switch the status of firstPartyCookiesEnabled.
                firstPartyCookiesEnabled = !firstPartyCookiesEnabled;

                // Update the menu checkbox.
                menuItem.setChecked(firstPartyCookiesEnabled);

                // Apply the new cookie status.
                cookieManager.setAcceptCookie(firstPartyCookiesEnabled);

                // Update the privacy icon.  `true` runs `invalidateOptionsMenu` as the last step.
                updatePrivacyIcons(true);

                // Display a `Snackbar`.
                if (firstPartyCookiesEnabled) {  // First-party cookies are enabled.
                    Snackbar.make(findViewById(R.id.main_webview), R.string.first_party_cookies_enabled, Snackbar.LENGTH_SHORT).show();
                } else if (javaScriptEnabled) {  // JavaScript is still enabled.
                    Snackbar.make(findViewById(R.id.main_webview), R.string.first_party_cookies_disabled, Snackbar.LENGTH_SHORT).show();
                } else {  // Privacy mode.
                    Snackbar.make(findViewById(R.id.main_webview), R.string.privacy_mode, Snackbar.LENGTH_SHORT).show();
                }

                // Reload the WebView.
                mainWebView.reload();
                return true;

            case R.id.toggle_third_party_cookies:
                if (Build.VERSION.SDK_INT >= 21) {
                    // Switch the status of thirdPartyCookiesEnabled.
                    thirdPartyCookiesEnabled = !thirdPartyCookiesEnabled;

                    // Update the menu checkbox.
                    menuItem.setChecked(thirdPartyCookiesEnabled);

                    // Apply the new cookie status.
                    cookieManager.setAcceptThirdPartyCookies(mainWebView, thirdPartyCookiesEnabled);

                    // Display a `Snackbar`.
                    if (thirdPartyCookiesEnabled) {
                        Snackbar.make(findViewById(R.id.main_webview), R.string.third_party_cookies_enabled, Snackbar.LENGTH_SHORT).show();
                    } else {
                        Snackbar.make(findViewById(R.id.main_webview), R.string.third_party_cookies_disabled, Snackbar.LENGTH_SHORT).show();
                    }

                    // Reload the WebView.
                    mainWebView.reload();
                } // Else do nothing because SDK < 21.
                return true;

            case R.id.toggle_dom_storage:
                // Switch the status of domStorageEnabled.
                domStorageEnabled = !domStorageEnabled;

                // Update the menu checkbox.
                menuItem.setChecked(domStorageEnabled);

                // Apply the new DOM Storage status.
                mainWebView.getSettings().setDomStorageEnabled(domStorageEnabled);

                // Update the privacy icon.  `true` runs `invalidateOptionsMenu` as the last step.
                updatePrivacyIcons(true);

                // Display a `Snackbar`.
                if (domStorageEnabled) {
                    Snackbar.make(findViewById(R.id.main_webview), R.string.dom_storage_enabled, Snackbar.LENGTH_SHORT).show();
                } else {
                    Snackbar.make(findViewById(R.id.main_webview), R.string.dom_storage_disabled, Snackbar.LENGTH_SHORT).show();
                }

                // Reload the WebView.
                mainWebView.reload();
                return true;

            // Form data can be removed once the minimum API >= 26.
            case R.id.toggle_save_form_data:
                // Switch the status of saveFormDataEnabled.
                saveFormDataEnabled = !saveFormDataEnabled;

                // Update the menu checkbox.
                menuItem.setChecked(saveFormDataEnabled);

                // Apply the new form data status.
                mainWebView.getSettings().setSaveFormData(saveFormDataEnabled);

                // Display a `Snackbar`.
                if (saveFormDataEnabled) {
                    Snackbar.make(findViewById(R.id.main_webview), R.string.form_data_enabled, Snackbar.LENGTH_SHORT).show();
                } else {
                    Snackbar.make(findViewById(R.id.main_webview), R.string.form_data_disabled, Snackbar.LENGTH_SHORT).show();
                }

                // Update the privacy icon.  `true` runs `invalidateOptionsMenu` as the last step.
                updatePrivacyIcons(true);

                // Reload the WebView.
                mainWebView.reload();
                return true;

            case R.id.clear_cookies:
                Snackbar.make(findViewById(R.id.main_webview), R.string.cookies_deleted, Snackbar.LENGTH_LONG)
                        .setAction(R.string.undo, v -> {
                            // Do nothing because everything will be handled by `onDismissed()` below.
                        })
                        .addCallback(new Snackbar.Callback() {
                            @SuppressLint("SwitchIntDef")  // Ignore the lint warning about not handling the other possible events as they are covered by `default:`.
                            @Override
                            public void onDismissed(Snackbar snackbar, int event) {
                                switch (event) {
                                    // The user pushed the undo button.
                                    case Snackbar.Callback.DISMISS_EVENT_ACTION:
                                        // Do nothing.
                                        break;

                                    // The snackbar was dismissed without the undo button being pushed.
                                    default:
                                        // `cookieManager.removeAllCookie()` varies by SDK.
                                        if (Build.VERSION.SDK_INT < 21) {
                                            cookieManager.removeAllCookie();
                                        } else {
                                            cookieManager.removeAllCookies(null);
                                        }
                                }
                            }
                        })
                        .show();
                return true;

            case R.id.clear_dom_storage:
                Snackbar.make(findViewById(R.id.main_webview), R.string.dom_storage_deleted, Snackbar.LENGTH_LONG)
                        .setAction(R.string.undo, v -> {
                            // Do nothing because everything will be handled by `onDismissed()` below.
                        })
                        .addCallback(new Snackbar.Callback() {
                            @SuppressLint("SwitchIntDef")  // Ignore the lint warning about not handling the other possible events as they are covered by `default:`.
                            @Override
                            public void onDismissed(Snackbar snackbar, int event) {
                                switch (event) {
                                    // The user pushed the undo button.
                                    case Snackbar.Callback.DISMISS_EVENT_ACTION:
                                        // Do nothing.
                                        break;

                                    // The snackbar was dismissed without the undo button being pushed.
                                    default:
                                        // Delete the DOM Storage.
                                        WebStorage webStorage = WebStorage.getInstance();
                                        webStorage.deleteAllData();

                                        // Initialize a handler to manually delete the DOM storage files and directories.
                                        Handler deleteDomStorageHandler = new Handler();

                                        // Setup a runnable to manually delete the DOM storage files and directories.
                                        Runnable deleteDomStorageRunnable = () -> {
                                            try {
                                                // A string array must be used because the directory contains a space and `Runtime.exec` will otherwise not escape the string correctly.
                                                Process deleteLocalStorageProcess = privacyBrowserRuntime.exec(new String[]{"rm", "-rf", privateDataDirectoryString + "/app_webview/Local Storage/"});

                                                // Multiple commands must be used because `Runtime.exec()` does not like `*`.
                                                Process deleteIndexProcess = privacyBrowserRuntime.exec("rm -rf " + privateDataDirectoryString + "/app_webview/IndexedDB");
                                                Process deleteQuotaManagerProcess = privacyBrowserRuntime.exec("rm -f " + privateDataDirectoryString + "/app_webview/QuotaManager");
                                                Process deleteQuotaManagerJournalProcess = privacyBrowserRuntime.exec("rm -f " + privateDataDirectoryString + "/app_webview/QuotaManager-journal");
                                                Process deleteDatabasesProcess = privacyBrowserRuntime.exec("rm -rf " + privateDataDirectoryString + "/app_webview/databases");

                                                // Wait for the processes to finish.
                                                deleteLocalStorageProcess.waitFor();
                                                deleteIndexProcess.waitFor();
                                                deleteQuotaManagerProcess.waitFor();
                                                deleteQuotaManagerJournalProcess.waitFor();
                                                deleteDatabasesProcess.waitFor();
                                            } catch (Exception exception) {
                                                // Do nothing if an error is thrown.
                                            }
                                        };

                                        // Manually delete the DOM storage files after 200 milliseconds.
                                        deleteDomStorageHandler.postDelayed(deleteDomStorageRunnable, 200);
                                }
                            }
                        })
                        .show();
                return true;

            // Form data can be remove once the minimum API >= 26.
            case R.id.clear_form_data:
                Snackbar.make(findViewById(R.id.main_webview), R.string.form_data_deleted, Snackbar.LENGTH_LONG)
                        .setAction(R.string.undo, v -> {
                            // Do nothing because everything will be handled by `onDismissed()` below.
                        })
                        .addCallback(new Snackbar.Callback() {
                            @SuppressLint("SwitchIntDef")  // Ignore the lint warning about not handling the other possible events as they are covered by `default:`.
                            @Override
                            public void onDismissed(Snackbar snackbar, int event) {
                                switch (event) {
                                    // The user pushed the undo button.
                                    case Snackbar.Callback.DISMISS_EVENT_ACTION:
                                        // Do nothing.
                                        break;

                                    // The snackbar was dismissed without the `Undo` button being pushed.
                                    default:
                                        // Delete the form data.
                                        WebViewDatabase mainWebViewDatabase = WebViewDatabase.getInstance(getApplicationContext());
                                        mainWebViewDatabase.clearFormData();
                                }
                            }
                        })
                        .show();
                return true;

            case R.id.easylist:
                // Toggle the EasyList status.
                easyListEnabled = !easyListEnabled;

                // Update the menu checkbox.
                menuItem.setChecked(easyListEnabled);

                // Reload the main WebView.
                mainWebView.reload();
                return true;

            case R.id.easyprivacy:
                // Toggle the EasyPrivacy status.
                easyPrivacyEnabled = !easyPrivacyEnabled;

                // Update the menu checkbox.
                menuItem.setChecked(easyPrivacyEnabled);

                // Reload the main WebView.
                mainWebView.reload();
                return true;

            case R.id.fanboys_annoyance_list:
                // Toggle Fanboy's Annoyance List status.
                fanboysAnnoyanceListEnabled = !fanboysAnnoyanceListEnabled;

                // Update the menu checkbox.
                menuItem.setChecked(fanboysAnnoyanceListEnabled);

                // Update the staus of Fanboy's Social Blocking List.
                MenuItem fanboysSocialBlockingListMenuItem = mainMenu.findItem(R.id.fanboys_social_blocking_list);
                fanboysSocialBlockingListMenuItem.setEnabled(!fanboysAnnoyanceListEnabled);

                // Reload the main WebView.
                mainWebView.reload();
                return true;

            case R.id.fanboys_social_blocking_list:
                // Toggle Fanboy's Social Blocking List status.
                fanboysSocialBlockingListEnabled = !fanboysSocialBlockingListEnabled;

                // Update the menu checkbox.
                menuItem.setChecked(fanboysSocialBlockingListEnabled);

                // Reload the main WebView.
                mainWebView.reload();
                return true;

            case R.id.ultraprivacy:
                // Toggle the UltraPrivacy status.
                ultraPrivacyEnabled = !ultraPrivacyEnabled;

                // Update the menu checkbox.
                menuItem.setChecked(ultraPrivacyEnabled);

                // Reload the main WebView.
                mainWebView.reload();
                return true;

            case R.id.block_all_third_party_requests:
                //Toggle the third-party requests blocker status.
                blockAllThirdPartyRequests = !blockAllThirdPartyRequests;

                // Update the menu checkbox.
                menuItem.setChecked(blockAllThirdPartyRequests);

                // Reload the main WebView.
                mainWebView.reload();
                return true;

            case R.id.user_agent_privacy_browser:
                // Update the user agent.
                mainWebView.getSettings().setUserAgentString(getResources().getStringArray(R.array.user_agent_data)[0]);

                // Reload the WebView.
                mainWebView.reload();
                return true;

            case R.id.user_agent_webview_default:
                // Update the user agent.
                mainWebView.getSettings().setUserAgentString("");

                // Reload the WebView.
                mainWebView.reload();
                return true;

            case R.id.user_agent_firefox_on_android:
                // Update the user agent.
                mainWebView.getSettings().setUserAgentString(getResources().getStringArray(R.array.user_agent_data)[2]);

                // Reload the WebView.
                mainWebView.reload();
                return true;

            case R.id.user_agent_chrome_on_android:
                // Update the user agent.
                mainWebView.getSettings().setUserAgentString(getResources().getStringArray(R.array.user_agent_data)[3]);

                // Reload the WebView.
                mainWebView.reload();
                return true;

            case R.id.user_agent_safari_on_ios:
                // Update the user agent.
                mainWebView.getSettings().setUserAgentString(getResources().getStringArray(R.array.user_agent_data)[4]);

                // Reload the WebView.
                mainWebView.reload();
                return true;

            case R.id.user_agent_firefox_on_linux:
                // Update the user agent.
                mainWebView.getSettings().setUserAgentString(getResources().getStringArray(R.array.user_agent_data)[5]);

                // Reload the WebView.
                mainWebView.reload();
                return true;

            case R.id.user_agent_chromium_on_linux:
                // Update the user agent.
                mainWebView.getSettings().setUserAgentString(getResources().getStringArray(R.array.user_agent_data)[6]);

                // Reload the WebView.
                mainWebView.reload();
                return true;

            case R.id.user_agent_firefox_on_windows:
                // Update the user agent.
                mainWebView.getSettings().setUserAgentString(getResources().getStringArray(R.array.user_agent_data)[7]);

                // Reload the WebView.
                mainWebView.reload();
                return true;

            case R.id.user_agent_chrome_on_windows:
                // Update the user agent.
                mainWebView.getSettings().setUserAgentString(getResources().getStringArray(R.array.user_agent_data)[8]);

                // Reload the WebView.
                mainWebView.reload();
                return true;

            case R.id.user_agent_edge_on_windows:
                // Update the user agent.
                mainWebView.getSettings().setUserAgentString(getResources().getStringArray(R.array.user_agent_data)[9]);

                // Reload the WebView.
                mainWebView.reload();
                return true;

            case R.id.user_agent_internet_explorer_on_windows:
                // Update the user agent.
                mainWebView.getSettings().setUserAgentString(getResources().getStringArray(R.array.user_agent_data)[10]);

                // Reload the WebView.
                mainWebView.reload();
                return true;

            case R.id.user_agent_safari_on_macos:
                // Update the user agent.
                mainWebView.getSettings().setUserAgentString(getResources().getStringArray(R.array.user_agent_data)[11]);

                // Reload the WebView.
                mainWebView.reload();
                return true;

            case R.id.user_agent_custom:
                // Update the user agent.
                mainWebView.getSettings().setUserAgentString(defaultCustomUserAgentString);

                // Reload the WebView.
                mainWebView.reload();
                return true;

            case R.id.font_size_twenty_five_percent:
                mainWebView.getSettings().setTextZoom(25);
                return true;

            case R.id.font_size_fifty_percent:
                mainWebView.getSettings().setTextZoom(50);
                return true;

            case R.id.font_size_seventy_five_percent:
                mainWebView.getSettings().setTextZoom(75);
                return true;

            case R.id.font_size_one_hundred_percent:
                mainWebView.getSettings().setTextZoom(100);
                return true;

            case R.id.font_size_one_hundred_twenty_five_percent:
                mainWebView.getSettings().setTextZoom(125);
                return true;

            case R.id.font_size_one_hundred_fifty_percent:
                mainWebView.getSettings().setTextZoom(150);
                return true;

            case R.id.font_size_one_hundred_seventy_five_percent:
                mainWebView.getSettings().setTextZoom(175);
                return true;

            case R.id.font_size_two_hundred_percent:
                mainWebView.getSettings().setTextZoom(200);
                return true;

            case R.id.swipe_to_refresh:
                // Get a handle for the swipe refresh layout.
                SwipeRefreshLayout swipeRefreshLayout = findViewById(R.id.swiperefreshlayout);

                // Toggle swipe to refresh.
                swipeRefreshLayout.setEnabled(!swipeRefreshLayout.isEnabled());
                return true;

            case R.id.display_images:
                if (mainWebView.getSettings().getLoadsImagesAutomatically()) {  // Images are currently loaded automatically.
                    mainWebView.getSettings().setLoadsImagesAutomatically(false);
                    mainWebView.reload();
                } else {  // Images are not currently loaded automatically.
                    mainWebView.getSettings().setLoadsImagesAutomatically(true);
                }
                return true;

            case R.id.night_mode:
                // Toggle night mode.
                nightMode = !nightMode;

                // Enable or disable JavaScript according to night mode, the global preference, and any domain settings.
                if (nightMode) {  // Night mode is enabled.  Enable JavaScript.
                    // Update the global variable.
                    javaScriptEnabled = true;
                } else if (domainSettingsApplied) {  // Night mode is disabled and domain settings are applied.  Set JavaScript according to the domain settings.
                    // Get the JavaScript preference that was stored the last time domain settings were loaded.
                    javaScriptEnabled = domainSettingsJavaScriptEnabled;
                } else {  // Night mode is disabled and domain settings are not applied.  Set JavaScript according to the global preference.
                    // Get a handle for the shared preference.
                    SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);

                    // Get the JavaScript preference.
                    javaScriptEnabled = sharedPreferences.getBoolean("javascript", false);
                }

                // Apply the JavaScript setting to the WebView.
                mainWebView.getSettings().setJavaScriptEnabled(javaScriptEnabled);

                // Update the privacy icons.
                updatePrivacyIcons(false);

                // Reload the website.
                mainWebView.reload();
                return true;

            case R.id.find_on_page:
                // Get a handle for the toolbar.
                Toolbar toolbar = findViewById(R.id.toolbar);

                // Hide the URL app bar.
                toolbar.setVisibility(View.GONE);

                // Show the Find on Page `RelativeLayout`.
                findOnPageLinearLayout.setVisibility(View.VISIBLE);

                // Display the keyboard.  We have to wait 200 ms before running the command to work around a bug in Android.
                // http://stackoverflow.com/questions/5520085/android-show-softkeyboard-with-showsoftinput-is-not-working
                findOnPageEditText.postDelayed(() -> {
                    // Set the focus on `findOnPageEditText`.
                    findOnPageEditText.requestFocus();

                    // Display the keyboard.  `0` sets no input flags.
                    inputMethodManager.showSoftInput(findOnPageEditText, 0);
                }, 200);
                return true;

            case R.id.view_source:
                // Launch the View Source activity.
                Intent viewSourceIntent = new Intent(this, ViewSourceActivity.class);
                startActivity(viewSourceIntent);
                return true;

            case R.id.share_url:
                // Setup the share string.
                String shareString = webViewTitle + " – " + urlTextBox.getText().toString();

                // Create the share intent.
                Intent shareIntent = new Intent(Intent.ACTION_SEND);
                shareIntent.putExtra(Intent.EXTRA_TEXT, shareString);
                shareIntent.setType("text/plain");

                // Make it so.
                startActivity(Intent.createChooser(shareIntent, getString(R.string.share_url)));
                return true;

            case R.id.print:
                // Get a `PrintManager` instance.
                PrintManager printManager = (PrintManager) getSystemService(Context.PRINT_SERVICE);

                // Convert `mainWebView` to `printDocumentAdapter`.
                PrintDocumentAdapter printDocumentAdapter = mainWebView.createPrintDocumentAdapter();

                // Remove the lint error below that `printManager` might be `null`.
                assert printManager != null;

                // Print the document.  The print attributes are `null`.
                printManager.print(getString(R.string.privacy_browser_web_page), printDocumentAdapter, null);
                return true;

            case R.id.open_with_app:
                openWithApp(formattedUrlString);
                return true;

            case R.id.open_with_browser:
                openWithBrowser(formattedUrlString);
                return true;

            case R.id.add_to_homescreen:
                // Show the alert dialog.
                DialogFragment createHomeScreenShortcutDialogFragment = new CreateHomeScreenShortcutDialog();
                createHomeScreenShortcutDialogFragment.show(getSupportFragmentManager(), getString(R.string.create_shortcut));

                //Everything else will be handled by the alert dialog and the associated listener below.
                return true;

            case R.id.proxy_through_orbot:
                // Toggle the proxy through Orbot variable.
                proxyThroughOrbot = !proxyThroughOrbot;

                // Apply the proxy through Orbot settings.
                applyProxyThroughOrbot(true);
                return true;

            case R.id.refresh:
                if (menuItem.getTitle().equals(getString(R.string.refresh))) {  // The refresh button was pushed.
                    // Reload the WebView.
                    mainWebView.reload();
                } else {  // The stop button was pushed.
                    // Stop the loading of the WebView.
                    mainWebView.stopLoading();
                }
                return true;

            case R.id.ad_consent:
                // Display the ad consent dialog.
                DialogFragment adConsentDialogFragment = new AdConsentDialog();
                adConsentDialogFragment.show(getSupportFragmentManager(), getString(R.string.ad_consent));
                return true;

            default:
                // Don't consume the event.
                return super.onOptionsItemSelected(menuItem);
        }
    }

    // removeAllCookies is deprecated, but it is required for API < 21.
    @SuppressWarnings("deprecation")
    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {
        int menuItemId = menuItem.getItemId();

        switch (menuItemId) {
            case R.id.home:
                loadUrl(homepage);
                break;

            case R.id.back:
                if (mainWebView.canGoBack()) {
                    // Reset the formatted URL string so the page will load correctly if blocking of third-party requests is enabled.
                    formattedUrlString = "";

                    // Set `navigatingHistory` so that the domain settings are applied when the new URL is loaded.
                    navigatingHistory = true;

                    // Load the previous website in the history.
                    mainWebView.goBack();
                }
                break;

            case R.id.forward:
                if (mainWebView.canGoForward()) {
                    // Reset the formatted URL string so the page will load correctly if blocking of third-party requests is enabled.
                    formattedUrlString = "";

                    // Set `navigatingHistory` so that the domain settings are applied when the new URL is loaded.
                    navigatingHistory = true;

                    // Load the next website in the history.
                    mainWebView.goForward();
                }
                break;

            case R.id.history:
                // Get the `WebBackForwardList`.
                WebBackForwardList webBackForwardList = mainWebView.copyBackForwardList();

                // Show the URL history dialog and name this instance `R.string.history`.
                DialogFragment urlHistoryDialogFragment = UrlHistoryDialog.loadBackForwardList(this, webBackForwardList);
                urlHistoryDialogFragment.show(getSupportFragmentManager(), getString(R.string.history));
                break;

            case R.id.requests:
                // Launch the requests activity.
                Intent requestsIntent = new Intent(this, RequestsActivity.class);
                startActivity(requestsIntent);
                break;

            case R.id.downloads:
                // Launch the system Download Manager.
                Intent downloadManagerIntent = new Intent(DownloadManager.ACTION_VIEW_DOWNLOADS);

                // Launch as a new task so that Download Manager and Privacy Browser show as separate windows in the recent tasks list.
                downloadManagerIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

                startActivity(downloadManagerIntent);
                break;

            case R.id.domains:
                // Set the flag to reapply the domain settings on restart when returning from Domain Settings.
                reapplyDomainSettingsOnRestart = true;
                currentDomainName = "";

                // Launch the domains activity.
                Intent domainsIntent = new Intent(this, DomainsActivity.class);
                startActivity(domainsIntent);
                break;

            case R.id.settings:
                // Set the flag to reapply app settings on restart when returning from Settings.
                reapplyAppSettingsOnRestart = true;

                // Set the flag to reapply the domain settings on restart when returning from Settings.
                reapplyDomainSettingsOnRestart = true;
                currentDomainName = "";

                // Launch the settings activity.
                Intent settingsIntent = new Intent(this, SettingsActivity.class);
                startActivity(settingsIntent);
                break;

            case R.id.import_export:
                // Launch the import/export activity.
                Intent importExportIntent = new Intent (this, ImportExportActivity.class);
                startActivity(importExportIntent);
                break;

            case R.id.logcat:
                // Launch the logcat activity.
                Intent logcatIntent = new Intent(this, LogcatActivity.class);
                startActivity(logcatIntent);
                break;

            case R.id.guide:
                // Launch `GuideActivity`.
                Intent guideIntent = new Intent(this, GuideActivity.class);
                startActivity(guideIntent);
                break;

            case R.id.about:
                // Launch `AboutActivity`.
                Intent aboutIntent = new Intent(this, AboutActivity.class);
                startActivity(aboutIntent);
                break;

            case R.id.clear_and_exit:
                // Close the bookmarks cursor and database.
                bookmarksCursor.close();
                bookmarksDatabaseHelper.close();

                // Get a handle for the shared preferences.
                SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);

                // Get the status of the clear everything preference.
                boolean clearEverything = sharedPreferences.getBoolean("clear_everything", true);

                // Clear cookies.
                if (clearEverything || sharedPreferences.getBoolean("clear_cookies", true)) {
                    // The command to remove cookies changed slightly in API 21.
                    if (Build.VERSION.SDK_INT >= 21) {
                        cookieManager.removeAllCookies(null);
                    } else {
                        cookieManager.removeAllCookie();
                    }

                    // Manually delete the cookies database, as `CookieManager` sometimes will not flush its changes to disk before `System.exit(0)` is run.
                    try {
                        // Two commands must be used because `Runtime.exec()` does not like `*`.
                        Process deleteCookiesProcess = privacyBrowserRuntime.exec("rm -f " + privateDataDirectoryString + "/app_webview/Cookies");
                        Process deleteCookiesJournalProcess = privacyBrowserRuntime.exec("rm -f " + privateDataDirectoryString + "/app_webview/Cookies-journal");

                        // Wait until the processes have finished.
                        deleteCookiesProcess.waitFor();
                        deleteCookiesJournalProcess.waitFor();
                    } catch (Exception exception) {
                        // Do nothing if an error is thrown.
                    }
                }

                // Clear DOM storage.
                if (clearEverything || sharedPreferences.getBoolean("clear_dom_storage", true)) {
                    // Ask `WebStorage` to clear the DOM storage.
                    WebStorage webStorage = WebStorage.getInstance();
                    webStorage.deleteAllData();

                    // Manually delete the DOM storage files and directories, as `WebStorage` sometimes will not flush its changes to disk before `System.exit(0)` is run.
                    try {
                        // A `String[]` must be used because the directory contains a space and `Runtime.exec` will otherwise not escape the string correctly.
                        Process deleteLocalStorageProcess = privacyBrowserRuntime.exec(new String[] {"rm", "-rf", privateDataDirectoryString + "/app_webview/Local Storage/"});

                        // Multiple commands must be used because `Runtime.exec()` does not like `*`.
                        Process deleteIndexProcess = privacyBrowserRuntime.exec("rm -rf " + privateDataDirectoryString + "/app_webview/IndexedDB");
                        Process deleteQuotaManagerProcess = privacyBrowserRuntime.exec("rm -f " + privateDataDirectoryString + "/app_webview/QuotaManager");
                        Process deleteQuotaManagerJournalProcess = privacyBrowserRuntime.exec("rm -f " + privateDataDirectoryString + "/app_webview/QuotaManager-journal");
                        Process deleteDatabaseProcess = privacyBrowserRuntime.exec("rm -rf " + privateDataDirectoryString + "/app_webview/databases");

                        // Wait until the processes have finished.
                        deleteLocalStorageProcess.waitFor();
                        deleteIndexProcess.waitFor();
                        deleteQuotaManagerProcess.waitFor();
                        deleteQuotaManagerJournalProcess.waitFor();
                        deleteDatabaseProcess.waitFor();
                    } catch (Exception exception) {
                        // Do nothing if an error is thrown.
                    }
                }

                // Clear form data if the API < 26.
                if ((Build.VERSION.SDK_INT < 26) && (clearEverything || sharedPreferences.getBoolean("clear_form_data", true))) {
                    WebViewDatabase webViewDatabase = WebViewDatabase.getInstance(this);
                    webViewDatabase.clearFormData();

                    // Manually delete the form data database, as `WebViewDatabase` sometimes will not flush its changes to disk before `System.exit(0)` is run.
                    try {
                        // A string array must be used because the database contains a space and `Runtime.exec` will not otherwise escape the string correctly.
                        Process deleteWebDataProcess = privacyBrowserRuntime.exec(new String[] {"rm", "-f", privateDataDirectoryString + "/app_webview/Web Data"});
                        Process deleteWebDataJournalProcess = privacyBrowserRuntime.exec(new String[] {"rm", "-f", privateDataDirectoryString + "/app_webview/Web Data-journal"});

                        // Wait until the processes have finished.
                        deleteWebDataProcess.waitFor();
                        deleteWebDataJournalProcess.waitFor();
                    } catch (Exception exception) {
                        // Do nothing if an error is thrown.
                    }
                }

                // Clear the cache.
                if (clearEverything || sharedPreferences.getBoolean("clear_cache", true)) {
                    // `true` includes disk files.
                    mainWebView.clearCache(true);

                    // Manually delete the cache directories.
                    try {
                        // Delete the main cache directory.
                        Process deleteCacheProcess = privacyBrowserRuntime.exec("rm -rf " + privateDataDirectoryString + "/cache");

                        // Delete the secondary `Service Worker` cache directory.
                        // A string array must be used because the directory contains a space and `Runtime.exec` will otherwise not escape the string correctly.
                        Process deleteServiceWorkerProcess = privacyBrowserRuntime.exec(new String[] {"rm", "-rf", privateDataDirectoryString + "/app_webview/Service Worker/"});

                        // Wait until the processes have finished.
                        deleteCacheProcess.waitFor();
                        deleteServiceWorkerProcess.waitFor();
                    } catch (Exception exception) {
                        // Do nothing if an error is thrown.
                    }
                }

                // Clear SSL certificate preferences.
                mainWebView.clearSslPreferences();

                // Clear the back/forward history.
                mainWebView.clearHistory();

                // Clear `formattedUrlString`.
                formattedUrlString = null;

                // Clear `customHeaders`.
                customHeaders.clear();

                // Destroy the internal state of `mainWebView`.
                mainWebView.destroy();

                // Manually delete the `app_webview` folder, which contains the cookies, DOM storage, form data, and `Service Worker` cache.
                // See `https://code.google.com/p/android/issues/detail?id=233826&thanks=233826&ts=1486670530`.
                if (clearEverything) {
                    try {
                        // Delete the folder.
                        Process deleteAppWebviewProcess = privacyBrowserRuntime.exec("rm -rf " + privateDataDirectoryString + "/app_webview");

                        // Wait until the process has finished.
                        deleteAppWebviewProcess.waitFor();
                    } catch (Exception exception) {
                        // Do nothing if an error is thrown.
                    }
                }

                // Close Privacy Browser.  `finishAndRemoveTask` also removes Privacy Browser from the recent app list.
                if (Build.VERSION.SDK_INT >= 21) {
                    finishAndRemoveTask();
                } else {
                    finish();
                }

                // Remove the terminated program from RAM.  The status code is `0`.
                System.exit(0);
                break;
        }

        // Get a handle for the drawer layout.
        DrawerLayout drawerLayout = findViewById(R.id.drawerlayout);

        // Close the navigation drawer.
        drawerLayout.closeDrawer(GravityCompat.START);
        return true;
    }

    @Override
    public void onPostCreate(Bundle savedInstanceState) {
        // Run the default commands.
        super.onPostCreate(savedInstanceState);

        // Sync the state of the DrawerToggle after onRestoreInstanceState has finished.
        actionBarDrawerToggle.syncState();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);

        // Get the status bar pixel size.
        int statusBarResourceId = getResources().getIdentifier("status_bar_height", "dimen", "android");
        int statusBarPixelSize = getResources().getDimensionPixelSize(statusBarResourceId);

        // Get the resource density.
        float screenDensity = getResources().getDisplayMetrics().density;

        // Recalculate the drawer header padding.
        drawerHeaderPaddingLeftAndRight = (int) (15 * screenDensity);
        drawerHeaderPaddingTop = statusBarPixelSize + (int) (4 * screenDensity);
        drawerHeaderPaddingBottom = (int) (8 * screenDensity);

        // Reload the ad for the free flavor if not in full screen mode.
        if (BuildConfig.FLAVOR.contentEquals("free") && !inFullScreenBrowsingMode) {
            // Reload the ad.  The AdView is destroyed and recreated, which changes the ID, every time it is reloaded to handle possible rotations.
            AdHelper.loadAd(findViewById(R.id.adview), getApplicationContext(), getString(R.string.ad_unit_id));
        }

        // `invalidateOptionsMenu` should recalculate the number of action buttons from the menu to display on the app bar, but it doesn't because of the this bug:
        // https://code.google.com/p/android/issues/detail?id=20493#c8
        // ActivityCompat.invalidateOptionsMenu(this);
    }

    @Override
    public void onCreateContextMenu(ContextMenu menu, View view, ContextMenu.ContextMenuInfo menuInfo) {
        // Store the `HitTestResult`.
        final WebView.HitTestResult hitTestResult = mainWebView.getHitTestResult();

        // Create strings.
        final String imageUrl;
        final String linkUrl;

        // Get a handle for the the clipboard and fragment managers.
        final ClipboardManager clipboardManager = (ClipboardManager) getSystemService(CLIPBOARD_SERVICE);
        FragmentManager fragmentManager = getSupportFragmentManager();

        // Remove the lint errors below that `clipboardManager` might be `null`.
        assert clipboardManager != null;

        switch (hitTestResult.getType()) {
            // `SRC_ANCHOR_TYPE` is a link.
            case WebView.HitTestResult.SRC_ANCHOR_TYPE:
                // Get the target URL.
                linkUrl = hitTestResult.getExtra();

                // Set the target URL as the title of the `ContextMenu`.
                menu.setHeaderTitle(linkUrl);

                // Add a Load URL entry.
                menu.add(R.string.load_url).setOnMenuItemClickListener((MenuItem item) -> {
                    loadUrl(linkUrl);
                    return false;
                });

                // Add a Copy URL entry.
                menu.add(R.string.copy_url).setOnMenuItemClickListener((MenuItem item) -> {
                    // Save the link URL in a `ClipData`.
                    ClipData srcAnchorTypeClipData = ClipData.newPlainText(getString(R.string.url), linkUrl);

                    // Set the `ClipData` as the clipboard's primary clip.
                    clipboardManager.setPrimaryClip(srcAnchorTypeClipData);
                    return false;
                });

                // Add a Download URL entry.
                menu.add(R.string.download_url).setOnMenuItemClickListener((MenuItem item) -> {
                    // Check if the download should be processed by an external app.
                    if (downloadWithExternalApp) {  // Download with an external app.
                        openUrlWithExternalApp(linkUrl);
                    } else {  // Download with Android's download manager.
                        // Check to see if the storage permission has already been granted.
                        if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_DENIED) {  // The storage permission needs to be requested.
                            // Store the variables for future use by `onRequestPermissionsResult()`.
                            downloadUrl = linkUrl;
                            downloadContentDisposition = "none";
                            downloadContentLength = -1;

                            // Show a dialog if the user has previously denied the permission.
                            if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {  // Show a dialog explaining the request first.
                                // Instantiate the download location permission alert dialog and set the download type to DOWNLOAD_FILE.
                                DialogFragment downloadLocationPermissionDialogFragment = DownloadLocationPermissionDialog.downloadType(DownloadLocationPermissionDialog.DOWNLOAD_FILE);

                                // Show the download location permission alert dialog.  The permission will be requested when the the dialog is closed.
                                downloadLocationPermissionDialogFragment.show(fragmentManager, getString(R.string.download_location));
                            } else {  // Show the permission request directly.
                                // Request the permission.  The download dialog will be launched by `onRequestPermissionResult()`.
                                ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, DOWNLOAD_FILE_REQUEST_CODE);
                            }
                        } else {  // The storage permission has already been granted.
                            // Get a handle for the download file alert dialog.
                            DialogFragment downloadFileDialogFragment = DownloadFileDialog.fromUrl(linkUrl, "none", -1);

                            // Show the download file alert dialog.
                            downloadFileDialogFragment.show(fragmentManager, getString(R.string.download));
                        }
                    }
                    return false;
                });

                // Add an Open with App entry.
                menu.add(R.string.open_with_app).setOnMenuItemClickListener((MenuItem item) -> {
                    openWithApp(linkUrl);
                    return false;
                });

                // Add an Open with Browser entry.
                menu.add(R.string.open_with_browser).setOnMenuItemClickListener((MenuItem item) -> {
                    openWithBrowser(linkUrl);
                    return false;
                });

                // Add a Cancel entry, which by default closes the context menu.
                menu.add(R.string.cancel);
                break;

            case WebView.HitTestResult.EMAIL_TYPE:
                // Get the target URL.
                linkUrl = hitTestResult.getExtra();

                // Set the target URL as the title of the `ContextMenu`.
                menu.setHeaderTitle(linkUrl);

                // Add a Write Email entry.
                menu.add(R.string.write_email).setOnMenuItemClickListener(item -> {
                    // Use `ACTION_SENDTO` instead of `ACTION_SEND` so that only email programs are launched.
                    Intent emailIntent = new Intent(Intent.ACTION_SENDTO);

                    // Parse the url and set it as the data for the `Intent`.
                    emailIntent.setData(Uri.parse("mailto:" + linkUrl));

                    // `FLAG_ACTIVITY_NEW_TASK` opens the email program in a new task instead as part of Privacy Browser.
                    emailIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

                    // Make it so.
                    startActivity(emailIntent);
                    return false;
                });

                // Add a Copy Email Address entry.
                menu.add(R.string.copy_email_address).setOnMenuItemClickListener(item -> {
                    // Save the email address in a `ClipData`.
                    ClipData srcEmailTypeClipData = ClipData.newPlainText(getString(R.string.email_address), linkUrl);

                    // Set the `ClipData` as the clipboard's primary clip.
                    clipboardManager.setPrimaryClip(srcEmailTypeClipData);
                    return false;
                });

                // Add a `Cancel` entry, which by default closes the `ContextMenu`.
                menu.add(R.string.cancel);
                break;

            // `IMAGE_TYPE` is an image.
            case WebView.HitTestResult.IMAGE_TYPE:
                // Get the image URL.
                imageUrl = hitTestResult.getExtra();

                // Set the image URL as the title of the `ContextMenu`.
                menu.setHeaderTitle(imageUrl);

                // Add a View Image entry.
                menu.add(R.string.view_image).setOnMenuItemClickListener(item -> {
                    loadUrl(imageUrl);
                    return false;
                });

                // Add a Download Image entry.
                menu.add(R.string.download_image).setOnMenuItemClickListener((MenuItem item) -> {
                    // Check if the download should be processed by an external app.
                    if (downloadWithExternalApp) {  // Download with an external app.
                        openUrlWithExternalApp(imageUrl);
                    } else {  // Download with Android's download manager.
                        // Check to see if the storage permission has already been granted.
                        if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_DENIED) {  // The storage permission needs to be requested.
                            // Store the image URL for use by `onRequestPermissionResult()`.
                            downloadImageUrl = imageUrl;

                            // Show a dialog if the user has previously denied the permission.
                            if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {  // Show a dialog explaining the request first.
                                // Instantiate the download location permission alert dialog and set the download type to DOWNLOAD_IMAGE.
                                DialogFragment downloadLocationPermissionDialogFragment = DownloadLocationPermissionDialog.downloadType(DownloadLocationPermissionDialog.DOWNLOAD_IMAGE);

                                // Show the download location permission alert dialog.  The permission will be requested when the dialog is closed.
                                downloadLocationPermissionDialogFragment.show(fragmentManager, getString(R.string.download_location));
                            } else {  // Show the permission request directly.
                                // Request the permission.  The download dialog will be launched by `onRequestPermissionResult().
                                ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, DOWNLOAD_IMAGE_REQUEST_CODE);
                            }
                        } else {  // The storage permission has already been granted.
                            // Get a handle for the download image alert dialog.
                            DialogFragment downloadImageDialogFragment = DownloadImageDialog.imageUrl(imageUrl);

                            // Show the download image alert dialog.
                            downloadImageDialogFragment.show(fragmentManager, getString(R.string.download));
                        }
                    }
                    return false;
                });

                // Add a Copy URL entry.
                menu.add(R.string.copy_url).setOnMenuItemClickListener(item -> {
                    // Save the image URL in a `ClipData`.
                    ClipData srcImageTypeClipData = ClipData.newPlainText(getString(R.string.url), imageUrl);

                    // Set the `ClipData` as the clipboard's primary clip.
                    clipboardManager.setPrimaryClip(srcImageTypeClipData);
                    return false;
                });

                // Add an Open with App entry.
                menu.add(R.string.open_with_app).setOnMenuItemClickListener((MenuItem item) -> {
                    openWithApp(imageUrl);
                    return false;
                });

                // Add an Open with Browser entry.
                menu.add(R.string.open_with_browser).setOnMenuItemClickListener((MenuItem item) -> {
                    openWithBrowser(imageUrl);
                    return false;
                });

                // Add a `Cancel` entry, which by default closes the `ContextMenu`.
                menu.add(R.string.cancel);
                break;


            // `SRC_IMAGE_ANCHOR_TYPE` is an image that is also a link.
            case WebView.HitTestResult.SRC_IMAGE_ANCHOR_TYPE:
                // Get the image URL.
                imageUrl = hitTestResult.getExtra();

                // Set the image URL as the title of the `ContextMenu`.
                menu.setHeaderTitle(imageUrl);

                // Add a `View Image` entry.
                menu.add(R.string.view_image).setOnMenuItemClickListener(item -> {
                    loadUrl(imageUrl);
                    return false;
                });

                // Add a `Download Image` entry.
                menu.add(R.string.download_image).setOnMenuItemClickListener((MenuItem item) -> {
                    // Check if the download should be processed by an external app.
                    if (downloadWithExternalApp) {  // Download with an external app.
                        openUrlWithExternalApp(imageUrl);
                    } else {  // Download with Android's download manager.
                        // Check to see if the storage permission has already been granted.
                        if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_DENIED) {  // The storage permission needs to be requested.
                            // Store the image URL for use by `onRequestPermissionResult()`.
                            downloadImageUrl = imageUrl;

                            // Show a dialog if the user has previously denied the permission.
                            if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {  // Show a dialog explaining the request first.
                                // Instantiate the download location permission alert dialog and set the download type to DOWNLOAD_IMAGE.
                                DialogFragment downloadLocationPermissionDialogFragment = DownloadLocationPermissionDialog.downloadType(DownloadLocationPermissionDialog.DOWNLOAD_IMAGE);

                                // Show the download location permission alert dialog.  The permission will be requested when the dialog is closed.
                                downloadLocationPermissionDialogFragment.show(fragmentManager, getString(R.string.download_location));
                            } else {  // Show the permission request directly.
                                // Request the permission.  The download dialog will be launched by `onRequestPermissionResult().
                                ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, DOWNLOAD_IMAGE_REQUEST_CODE);
                            }
                        } else {  // The storage permission has already been granted.
                            // Get a handle for the download image alert dialog.
                            DialogFragment downloadImageDialogFragment = DownloadImageDialog.imageUrl(imageUrl);

                            // Show the download image alert dialog.
                            downloadImageDialogFragment.show(fragmentManager, getString(R.string.download));
                        }
                    }
                    return false;
                });

                // Add a `Copy URL` entry.
                menu.add(R.string.copy_url).setOnMenuItemClickListener(item -> {
                    // Save the image URL in a `ClipData`.
                    ClipData srcImageAnchorTypeClipData = ClipData.newPlainText(getString(R.string.url), imageUrl);

                    // Set the `ClipData` as the clipboard's primary clip.
                    clipboardManager.setPrimaryClip(srcImageAnchorTypeClipData);
                    return false;
                });

                // Add an Open with App entry.
                menu.add(R.string.open_with_app).setOnMenuItemClickListener((MenuItem item) -> {
                    openWithApp(imageUrl);
                    return false;
                });

                // Add an Open with Browser entry.
                menu.add(R.string.open_with_browser).setOnMenuItemClickListener((MenuItem item) -> {
                    openWithBrowser(imageUrl);
                    return false;
                });

                // Add a `Cancel` entry, which by default closes the `ContextMenu`.
                menu.add(R.string.cancel);
                break;
        }
    }

    @Override
    public void onCreateBookmark(DialogFragment dialogFragment) {
        // Get the `EditTexts` from the `dialogFragment`.
        EditText createBookmarkNameEditText = dialogFragment.getDialog().findViewById(R.id.create_bookmark_name_edittext);
        EditText createBookmarkUrlEditText = dialogFragment.getDialog().findViewById(R.id.create_bookmark_url_edittext);

        // Extract the strings from the `EditTexts`.
        String bookmarkNameString = createBookmarkNameEditText.getText().toString();
        String bookmarkUrlString = createBookmarkUrlEditText.getText().toString();

        // Convert the favoriteIcon Bitmap to a byte array.  `0` is for lossless compression (the only option for a PNG).
        ByteArrayOutputStream favoriteIconByteArrayOutputStream = new ByteArrayOutputStream();
        favoriteIconBitmap.compress(Bitmap.CompressFormat.PNG, 0, favoriteIconByteArrayOutputStream);
        byte[] favoriteIconByteArray = favoriteIconByteArrayOutputStream.toByteArray();

        // Display the new bookmark below the current items in the (0 indexed) list.
        int newBookmarkDisplayOrder = bookmarksListView.getCount();

        // Create the bookmark.
        bookmarksDatabaseHelper.createBookmark(bookmarkNameString, bookmarkUrlString, currentBookmarksFolder, newBookmarkDisplayOrder, favoriteIconByteArray);

        // Update the bookmarks cursor with the current contents of this folder.
        bookmarksCursor = bookmarksDatabaseHelper.getBookmarksByDisplayOrder(currentBookmarksFolder);

        // Update the `ListView`.
        bookmarksCursorAdapter.changeCursor(bookmarksCursor);

        // Scroll to the new bookmark.
        bookmarksListView.setSelection(newBookmarkDisplayOrder);
    }

    @Override
    public void onCreateBookmarkFolder(DialogFragment dialogFragment) {
        // Get handles for the views in `dialogFragment`.
        EditText createFolderNameEditText = dialogFragment.getDialog().findViewById(R.id.create_folder_name_edittext);
        RadioButton defaultFolderIconRadioButton = dialogFragment.getDialog().findViewById(R.id.create_folder_default_icon_radiobutton);
        ImageView folderIconImageView = dialogFragment.getDialog().findViewById(R.id.create_folder_default_icon);

        // Get new folder name string.
        String folderNameString = createFolderNameEditText.getText().toString();

        // Get the new folder icon `Bitmap`.
        Bitmap folderIconBitmap;
        if (defaultFolderIconRadioButton.isChecked()) {  // Use the default folder icon.
            // Get the default folder icon and convert it to a `Bitmap`.
            Drawable folderIconDrawable = folderIconImageView.getDrawable();
            BitmapDrawable folderIconBitmapDrawable = (BitmapDrawable) folderIconDrawable;
            folderIconBitmap = folderIconBitmapDrawable.getBitmap();
        } else {  // Use the `WebView` favorite icon.
            folderIconBitmap = favoriteIconBitmap;
        }

        // Convert `folderIconBitmap` to a byte array.  `0` is for lossless compression (the only option for a PNG).
        ByteArrayOutputStream folderIconByteArrayOutputStream = new ByteArrayOutputStream();
        folderIconBitmap.compress(Bitmap.CompressFormat.PNG, 0, folderIconByteArrayOutputStream);
        byte[] folderIconByteArray = folderIconByteArrayOutputStream.toByteArray();

        // Move all the bookmarks down one in the display order.
        for (int i = 0; i < bookmarksListView.getCount(); i++) {
            int databaseId = (int) bookmarksListView.getItemIdAtPosition(i);
            bookmarksDatabaseHelper.updateDisplayOrder(databaseId, i + 1);
        }

        // Create the folder, which will be placed at the top of the `ListView`.
        bookmarksDatabaseHelper.createFolder(folderNameString, currentBookmarksFolder, folderIconByteArray);

        // Update the bookmarks cursor with the current contents of this folder.
        bookmarksCursor = bookmarksDatabaseHelper.getBookmarksByDisplayOrder(currentBookmarksFolder);

        // Update the `ListView`.
        bookmarksCursorAdapter.changeCursor(bookmarksCursor);

        // Scroll to the new folder.
        bookmarksListView.setSelection(0);
    }

    @Override
    public void onCreateHomeScreenShortcut(DialogFragment dialogFragment) {
        // Get the shortcut name.
        EditText shortcutNameEditText = dialogFragment.getDialog().findViewById(R.id.shortcut_name_edittext);
        String shortcutNameString = shortcutNameEditText.getText().toString();

        // Convert the favorite icon bitmap to an `Icon`.  `IconCompat` is required until API >= 26.
        IconCompat favoriteIcon = IconCompat.createWithBitmap(favoriteIconBitmap);

        // Setup the shortcut intent.
        Intent shortcutIntent = new Intent(Intent.ACTION_VIEW);
        shortcutIntent.setData(Uri.parse(formattedUrlString));

        // Create a shortcut info builder.  The shortcut name becomes the shortcut ID.
        ShortcutInfoCompat.Builder shortcutInfoBuilder = new ShortcutInfoCompat.Builder(this, shortcutNameString);

        // Add the required fields to the shortcut info builder.
        shortcutInfoBuilder.setIcon(favoriteIcon);
        shortcutInfoBuilder.setIntent(shortcutIntent);
        shortcutInfoBuilder.setShortLabel(shortcutNameString);

        // Request the pin.  `ShortcutManagerCompat` can be switched to `ShortcutManager` once API >= 26.
        ShortcutManagerCompat.requestPinShortcut(this, shortcutInfoBuilder.build(), null);
    }

    @Override
    public void onCloseDownloadLocationPermissionDialog(int downloadType) {
        switch (downloadType) {
            case DownloadLocationPermissionDialog.DOWNLOAD_FILE:
                // Request the WRITE_EXTERNAL_STORAGE permission with a file request code.
                ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, DOWNLOAD_FILE_REQUEST_CODE);
                break;

            case DownloadLocationPermissionDialog.DOWNLOAD_IMAGE:
                // Request the WRITE_EXTERNAL_STORAGE permission with an image request code.
                ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, DOWNLOAD_IMAGE_REQUEST_CODE);
                break;
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        // Get a handle for the fragment manager.
        FragmentManager fragmentManager = getSupportFragmentManager();

        switch (requestCode) {
            case DOWNLOAD_FILE_REQUEST_CODE:
                // Show the download file alert dialog.  When the dialog closes, the correct command will be used based on the permission status.
                DialogFragment downloadFileDialogFragment = DownloadFileDialog.fromUrl(downloadUrl, downloadContentDisposition, downloadContentLength);

                // On API 23, displaying the fragment must be delayed or the app will crash.
                if (Build.VERSION.SDK_INT == 23) {
                    new Handler().postDelayed(() -> downloadFileDialogFragment.show(fragmentManager, getString(R.string.download)), 500);
                } else {
                    downloadFileDialogFragment.show(fragmentManager, getString(R.string.download));
                }

                // Reset the download variables.
                downloadUrl = "";
                downloadContentDisposition = "";
                downloadContentLength = 0;
                break;

            case DOWNLOAD_IMAGE_REQUEST_CODE:
                // Show the download image alert dialog.  When the dialog closes, the correct command will be used based on the permission status.
                DialogFragment downloadImageDialogFragment = DownloadImageDialog.imageUrl(downloadImageUrl);

                // On API 23, displaying the fragment must be delayed or the app will crash.
                if (Build.VERSION.SDK_INT == 23) {
                    new Handler().postDelayed(() -> downloadImageDialogFragment.show(fragmentManager, getString(R.string.download)), 500);
                } else {
                    downloadImageDialogFragment.show(fragmentManager, getString(R.string.download));
                }

                // Reset the image URL variable.
                downloadImageUrl = "";
                break;
        }
    }

    @Override
    public void onDownloadImage(DialogFragment dialogFragment, String imageUrl) {
        // Download the image if it has an HTTP or HTTPS URI.
        if (imageUrl.startsWith("http")) {
            // Get a handle for the system `DOWNLOAD_SERVICE`.
            DownloadManager downloadManager = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);

            // Parse `imageUrl`.
            DownloadManager.Request downloadRequest = new DownloadManager.Request(Uri.parse(imageUrl));

            // Pass cookies to download manager if cookies are enabled.  This is required to download images from websites that require a login.
            // Code contributed 2017 Hendrik Knackstedt.  Copyright assigned to Soren Stoutner <soren@stoutner.com>.
            if (firstPartyCookiesEnabled) {
                // Get the cookies for `imageUrl`.
                String cookies = cookieManager.getCookie(imageUrl);

                // Add the cookies to `downloadRequest`.  In the HTTP request header, cookies are named `Cookie`.
                downloadRequest.addRequestHeader("Cookie", cookies);
            }

            // Get the file name from the dialog fragment.
            EditText downloadImageNameEditText = dialogFragment.getDialog().findViewById(R.id.download_image_name);
            String imageName = downloadImageNameEditText.getText().toString();

            // Specify the download location.
            if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {  // External write permission granted.
                // Download to the public download directory.
                downloadRequest.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, imageName);
            } else {  // External write permission denied.
                // Download to the app's external download directory.
                downloadRequest.setDestinationInExternalFilesDir(this, Environment.DIRECTORY_DOWNLOADS, imageName);
            }

            // Allow `MediaScanner` to index the download if it is a media file.
            downloadRequest.allowScanningByMediaScanner();

            // Add the URL as the description for the download.
            downloadRequest.setDescription(imageUrl);

            // Show the download notification after the download is completed.
            downloadRequest.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);

            // Remove the lint warning below that `downloadManager` might be `null`.
            assert downloadManager != null;

            // Initiate the download.
            downloadManager.enqueue(downloadRequest);
        } else {  // The image is not an HTTP or HTTPS URI.
            Snackbar.make(mainWebView, R.string.cannot_download_image, Snackbar.LENGTH_INDEFINITE).show();
        }
    }

    @Override
    public void onDownloadFile(DialogFragment dialogFragment, String downloadUrl) {
        // Download the file if it has an HTTP or HTTPS URI.
        if (downloadUrl.startsWith("http")) {
            // Get a handle for the system `DOWNLOAD_SERVICE`.
            DownloadManager downloadManager = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);

            // Parse `downloadUrl`.
            DownloadManager.Request downloadRequest = new DownloadManager.Request(Uri.parse(downloadUrl));

            // Pass cookies to download manager if cookies are enabled.  This is required to download files from websites that require a login.
            // Code contributed 2017 Hendrik Knackstedt.  Copyright assigned to Soren Stoutner <soren@stoutner.com>.
            if (firstPartyCookiesEnabled) {
                // Get the cookies for `downloadUrl`.
                String cookies = cookieManager.getCookie(downloadUrl);

                // Add the cookies to `downloadRequest`.  In the HTTP request header, cookies are named `Cookie`.
                downloadRequest.addRequestHeader("Cookie", cookies);
            }

            // Get the file name from the dialog fragment.
            EditText downloadFileNameEditText = dialogFragment.getDialog().findViewById(R.id.download_file_name);
            String fileName = downloadFileNameEditText.getText().toString();

            // Specify the download location.
            if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {  // External write permission granted.
                // Download to the public download directory.
                downloadRequest.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, fileName);
            } else {  // External write permission denied.
                // Download to the app's external download directory.
                downloadRequest.setDestinationInExternalFilesDir(this, Environment.DIRECTORY_DOWNLOADS, fileName);
            }

            // Allow `MediaScanner` to index the download if it is a media file.
            downloadRequest.allowScanningByMediaScanner();

            // Add the URL as the description for the download.
            downloadRequest.setDescription(downloadUrl);

            // Show the download notification after the download is completed.
            downloadRequest.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);

            // Remove the lint warning below that `downloadManager` might be `null`.
            assert downloadManager != null;

            // Initiate the download.
            downloadManager.enqueue(downloadRequest);
        } else {  // The download is not an HTTP or HTTPS URI.
            Snackbar.make(mainWebView, R.string.cannot_download_file, Snackbar.LENGTH_INDEFINITE).show();
        }
    }

    @Override
    public void onSaveBookmark(DialogFragment dialogFragment, int selectedBookmarkDatabaseId) {
        // Get handles for the views from `dialogFragment`.
        EditText editBookmarkNameEditText = dialogFragment.getDialog().findViewById(R.id.edit_bookmark_name_edittext);
        EditText editBookmarkUrlEditText = dialogFragment.getDialog().findViewById(R.id.edit_bookmark_url_edittext);
        RadioButton currentBookmarkIconRadioButton = dialogFragment.getDialog().findViewById(R.id.edit_bookmark_current_icon_radiobutton);

        // Store the bookmark strings.
        String bookmarkNameString = editBookmarkNameEditText.getText().toString();
        String bookmarkUrlString = editBookmarkUrlEditText.getText().toString();

        // Update the bookmark.
        if (currentBookmarkIconRadioButton.isChecked()) {  // Update the bookmark without changing the favorite icon.
            bookmarksDatabaseHelper.updateBookmark(selectedBookmarkDatabaseId, bookmarkNameString, bookmarkUrlString);
        } else {  // Update the bookmark using the `WebView` favorite icon.
            // Convert the favorite icon to a byte array.  `0` is for lossless compression (the only option for a PNG).
            ByteArrayOutputStream newFavoriteIconByteArrayOutputStream = new ByteArrayOutputStream();
            favoriteIconBitmap.compress(Bitmap.CompressFormat.PNG, 0, newFavoriteIconByteArrayOutputStream);
            byte[] newFavoriteIconByteArray = newFavoriteIconByteArrayOutputStream.toByteArray();

            //  Update the bookmark and the favorite icon.
            bookmarksDatabaseHelper.updateBookmark(selectedBookmarkDatabaseId, bookmarkNameString, bookmarkUrlString, newFavoriteIconByteArray);
        }

        // Update the bookmarks cursor with the current contents of this folder.
        bookmarksCursor = bookmarksDatabaseHelper.getBookmarksByDisplayOrder(currentBookmarksFolder);

        // Update the `ListView`.
        bookmarksCursorAdapter.changeCursor(bookmarksCursor);
    }

    @Override
    public void onSaveBookmarkFolder(DialogFragment dialogFragment, int selectedFolderDatabaseId) {
        // Get handles for the views from `dialogFragment`.
        EditText editFolderNameEditText = dialogFragment.getDialog().findViewById(R.id.edit_folder_name_edittext);
        RadioButton currentFolderIconRadioButton = dialogFragment.getDialog().findViewById(R.id.edit_folder_current_icon_radiobutton);
        RadioButton defaultFolderIconRadioButton = dialogFragment.getDialog().findViewById(R.id.edit_folder_default_icon_radiobutton);
        ImageView folderIconImageView = dialogFragment.getDialog().findViewById(R.id.edit_folder_default_icon_imageview);

        // Get the new folder name.
        String newFolderNameString = editFolderNameEditText.getText().toString();

        // Check if the favorite icon has changed.
        if (currentFolderIconRadioButton.isChecked()) {  // Only the name has changed.
            // Update the name in the database.
            bookmarksDatabaseHelper.updateFolder(selectedFolderDatabaseId, oldFolderNameString, newFolderNameString);
        } else if (!currentFolderIconRadioButton.isChecked() && newFolderNameString.equals(oldFolderNameString)) {  // Only the icon has changed.
            // Get the new folder icon `Bitmap`.
            Bitmap folderIconBitmap;
            if (defaultFolderIconRadioButton.isChecked()) {
                // Get the default folder icon and convert it to a `Bitmap`.
                Drawable folderIconDrawable = folderIconImageView.getDrawable();
                BitmapDrawable folderIconBitmapDrawable = (BitmapDrawable) folderIconDrawable;
                folderIconBitmap = folderIconBitmapDrawable.getBitmap();
            } else {  // Use the `WebView` favorite icon.
                folderIconBitmap = favoriteIconBitmap;
            }

            // Convert the folder `Bitmap` to a byte array.  `0` is for lossless compression (the only option for a PNG).
            ByteArrayOutputStream folderIconByteArrayOutputStream = new ByteArrayOutputStream();
            folderIconBitmap.compress(Bitmap.CompressFormat.PNG, 0, folderIconByteArrayOutputStream);
            byte[] folderIconByteArray = folderIconByteArrayOutputStream.toByteArray();

            // Update the folder icon in the database.
            bookmarksDatabaseHelper.updateFolder(selectedFolderDatabaseId, folderIconByteArray);
        } else {  // The folder icon and the name have changed.
            // Get the new folder icon `Bitmap`.
            Bitmap folderIconBitmap;
            if (defaultFolderIconRadioButton.isChecked()) {
                // Get the default folder icon and convert it to a `Bitmap`.
                Drawable folderIconDrawable = folderIconImageView.getDrawable();
                BitmapDrawable folderIconBitmapDrawable = (BitmapDrawable) folderIconDrawable;
                folderIconBitmap = folderIconBitmapDrawable.getBitmap();
            } else {  // Use the `WebView` favorite icon.
                folderIconBitmap = MainWebViewActivity.favoriteIconBitmap;
            }

            // Convert the folder `Bitmap` to a byte array.  `0` is for lossless compression (the only option for a PNG).
            ByteArrayOutputStream folderIconByteArrayOutputStream = new ByteArrayOutputStream();
            folderIconBitmap.compress(Bitmap.CompressFormat.PNG, 0, folderIconByteArrayOutputStream);
            byte[] folderIconByteArray = folderIconByteArrayOutputStream.toByteArray();

            // Update the folder name and icon in the database.
            bookmarksDatabaseHelper.updateFolder(selectedFolderDatabaseId, oldFolderNameString, newFolderNameString, folderIconByteArray);
        }

        // Update the bookmarks cursor with the current contents of this folder.
        bookmarksCursor = bookmarksDatabaseHelper.getBookmarksByDisplayOrder(currentBookmarksFolder);

        // Update the `ListView`.
        bookmarksCursorAdapter.changeCursor(bookmarksCursor);
    }

    @Override
    public void onHttpAuthenticationCancel() {
        // Cancel the `HttpAuthHandler`.
        httpAuthHandler.cancel();
    }

    @Override
    public void onHttpAuthenticationProceed(DialogFragment dialogFragment) {
        // Get handles for the `EditTexts`.
        EditText usernameEditText = dialogFragment.getDialog().findViewById(R.id.http_authentication_username);
        EditText passwordEditText = dialogFragment.getDialog().findViewById(R.id.http_authentication_password);

        // Proceed with the HTTP authentication.
        httpAuthHandler.proceed(usernameEditText.getText().toString(), passwordEditText.getText().toString());
    }

    public void viewSslCertificate(View view) {
        // Show the `ViewSslCertificateDialog` `AlertDialog` and name this instance `@string/view_ssl_certificate`.
        DialogFragment viewSslCertificateDialogFragment = new ViewSslCertificateDialog();
        viewSslCertificateDialogFragment.show(getSupportFragmentManager(), getString(R.string.view_ssl_certificate));
    }

    @Override
    public void onSslErrorCancel() {
        sslErrorHandler.cancel();
    }

    @Override
    public void onSslErrorProceed() {
        sslErrorHandler.proceed();
    }

    @Override
    public void onPinnedMismatchBack() {
        if (mainWebView.canGoBack()) {  // There is a back page in the history.
            // Reset the formatted URL string so the page will load correctly if blocking of third-party requests is enabled.
            formattedUrlString = "";

            // Set `navigatingHistory` so that the domain settings are applied when the new URL is loaded.
            navigatingHistory = true;

            // Go back.
            mainWebView.goBack();
        } else {  // There are no pages to go back to.
            // Load a blank page
            loadUrl("");
        }
    }

    @Override
    public void onPinnedMismatchProceed() {
        // Do not check the pinned information for this domain again until the domain changes.
        ignorePinnedDomainInformation = true;
    }

    @Override
    public void onUrlHistoryEntrySelected(int moveBackOrForwardSteps) {
        // Reset the formatted URL string so the page will load correctly if blocking of third-party requests is enabled.
        formattedUrlString = "";

        // Set `navigatingHistory` so that the domain settings are applied when the new URL is loaded.
        navigatingHistory = true;

        // Load the history entry.
        mainWebView.goBackOrForward(moveBackOrForwardSteps);
    }

    @Override
    public void onClearHistory() {
        // Clear the history.
        mainWebView.clearHistory();
    }

    // Override `onBackPressed` to handle the navigation drawer and `mainWebView`.
    @Override
    public void onBackPressed() {
        // Get a handle for the drawer layout.
        DrawerLayout drawerLayout = findViewById(R.id.drawerlayout);

        if (drawerLayout.isDrawerVisible(GravityCompat.START)) {  // The navigation drawer is open.
            // Close the navigation drawer.
            drawerLayout.closeDrawer(GravityCompat.START);
        } else if (drawerLayout.isDrawerVisible(GravityCompat.END)){  // The bookmarks drawer is open.
            if (currentBookmarksFolder.isEmpty()) {  // The home folder is displayed.
                // close the bookmarks drawer.
                drawerLayout.closeDrawer(GravityCompat.END);
            } else {  // A subfolder is displayed.
                // Place the former parent folder in `currentFolder`.
                currentBookmarksFolder = bookmarksDatabaseHelper.getParentFolderName(currentBookmarksFolder);

                // Load the new folder.
                loadBookmarksFolder();
            }

        } else if (mainWebView.canGoBack()) {  // There is at least one item in the `WebView` history.
            // Reset the formatted URL string so the page will load correctly if blocking of third-party requests is enabled.
            formattedUrlString = "";

            // Set `navigatingHistory` so that the domain settings are applied when the new URL is loaded.
            navigatingHistory = true;

            // Go back.
            mainWebView.goBack();
        } else {  // There isn't anything to do in Privacy Browser.
            // Pass `onBackPressed()` to the system.
            super.onBackPressed();
        }
    }

    // Process the results of an upload file chooser.  Currently there is only one `startActivityForResult` in this activity, so the request code, used to differentiate them, is ignored.
    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        // File uploads only work on API >= 21.
        if (Build.VERSION.SDK_INT >= 21) {
            // Pass the file to the WebView.
            fileChooserCallback.onReceiveValue(WebChromeClient.FileChooserParams.parseResult(resultCode, data));
        }
    }

    private void loadUrlFromTextBox() {
        // Get the text from urlTextBox and convert it to a string.  trim() removes white spaces from the beginning and end of the string.
        String unformattedUrlString = urlTextBox.getText().toString().trim();

        // Check to see if `unformattedUrlString` is a valid URL.  Otherwise, convert it into a search.
        if (unformattedUrlString.startsWith("content://")) {
            // Load the entire content URL.
            formattedUrlString = unformattedUrlString;
        } else if (Patterns.WEB_URL.matcher(unformattedUrlString).matches() || unformattedUrlString.startsWith("http://") || unformattedUrlString.startsWith("https://")
                || unformattedUrlString.startsWith("file://")) {
            // Add `https://` at the beginning if there is no protocol.  Otherwise the app will segfault.
            if (!unformattedUrlString.startsWith("http") && !unformattedUrlString.startsWith("file://") && !unformattedUrlString.startsWith("content://")) {
                unformattedUrlString = "https://" + unformattedUrlString;
            }

            // Initialize `unformattedUrl`.
            URL unformattedUrl = null;

            // Convert `unformattedUrlString` to a `URL`, then to a `URI`, and then back to a `String`, which sanitizes the input and adds in any missing components.
            try {
                unformattedUrl = new URL(unformattedUrlString);
            } catch (MalformedURLException e) {
                e.printStackTrace();
            }

            // The ternary operator (? :) makes sure that a null pointer exception is not thrown, which would happen if `.get` was called on a `null` value.
            String scheme = unformattedUrl != null ? unformattedUrl.getProtocol() : null;
            String authority = unformattedUrl != null ? unformattedUrl.getAuthority() : null;
            String path = unformattedUrl != null ? unformattedUrl.getPath() : null;
            String query = unformattedUrl != null ? unformattedUrl.getQuery() : null;
            String fragment = unformattedUrl != null ? unformattedUrl.getRef() : null;

            // Build the URI.
            Uri.Builder formattedUri = new Uri.Builder();
            formattedUri.scheme(scheme).authority(authority).path(path).query(query).fragment(fragment);

            // Decode `formattedUri` as a `String` in `UTF-8`.
            try {
                formattedUrlString = URLDecoder.decode(formattedUri.build().toString(), "UTF-8");
            } catch (UnsupportedEncodingException exception) {
                // Load a blank string.
                formattedUrlString = "";
            }
        } else if (unformattedUrlString.isEmpty()){  // Load a blank web site.
            // Load a blank string.
            formattedUrlString = "";
        } else {  // Search for the contents of the URL box.
            // Create an encoded URL String.
            String encodedUrlString;

            // Sanitize the search input.
            try {
                encodedUrlString = URLEncoder.encode(unformattedUrlString, "UTF-8");
            } catch (UnsupportedEncodingException exception) {
                encodedUrlString = "";
            }

            // Add the base search URL.
            formattedUrlString = searchURL + encodedUrlString;
        }

        // Clear the focus from the URL text box.  Otherwise, proximate typing in the box will retain the colorized formatting instead of being reset during refocus.
        urlTextBox.clearFocus();

        // Make it so.
        loadUrl(formattedUrlString);
    }

    private void loadUrl(String url) {// Apply any custom domain settings.
        // Set the URL as the formatted URL string so that checking third-party requests works correctly.
        formattedUrlString = url;

        // Apply the domain settings.
        applyDomainSettings(url, true, false);

        // If loading a website, set `urlIsLoading` to prevent changes in the user agent on websites with redirects from reloading the current website.
        urlIsLoading = !url.equals("");

        // Load the URL.
        mainWebView.loadUrl(url, customHeaders);
    }

    public void findPreviousOnPage(View view) {
        // Go to the previous highlighted phrase on the page.  `false` goes backwards instead of forwards.
        mainWebView.findNext(false);
    }

    public void findNextOnPage(View view) {
        // Go to the next highlighted phrase on the page. `true` goes forwards instead of backwards.
        mainWebView.findNext(true);
    }

    public void closeFindOnPage(View view) {
        // Delete the contents of `find_on_page_edittext`.
        findOnPageEditText.setText(null);

        // Clear the highlighted phrases.
        mainWebView.clearMatches();

        // Hide the Find on Page `RelativeLayout`.
        findOnPageLinearLayout.setVisibility(View.GONE);

        // Get a handle for the toolbar.
        Toolbar toolbar = findViewById(R.id.toolbar);

        // Show the toolbar.
        toolbar.setVisibility(View.VISIBLE);

        // Hide the keyboard so we can see the webpage.  `0` indicates no additional flags.
        inputMethodManager.hideSoftInputFromWindow(mainWebView.getWindowToken(), 0);
    }

    private void applyAppSettings() {
        // Get a handle for the shared preferences.
        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);

        // Store the values from the shared preferences in variables.
        incognitoModeEnabled = sharedPreferences.getBoolean("incognito_mode", false);
        boolean doNotTrackEnabled = sharedPreferences.getBoolean("do_not_track", false);
        proxyThroughOrbot = sharedPreferences.getBoolean("proxy_through_orbot", false);
        fullScreenBrowsingModeEnabled = sharedPreferences.getBoolean("full_screen_browsing_mode", false);
        hideSystemBarsOnFullscreen = sharedPreferences.getBoolean("hide_system_bars", false);
        translucentNavigationBarOnFullscreen = sharedPreferences.getBoolean("translucent_navigation_bar", true);
        downloadWithExternalApp = sharedPreferences.getBoolean("download_with_external_app", false);

        // Apply the proxy through Orbot settings.
        applyProxyThroughOrbot(false);

        // Set Do Not Track status.
        if (doNotTrackEnabled) {
            customHeaders.put("DNT", "1");
        } else {
            customHeaders.remove("DNT");
        }

        // Get handles for the views that need to be modified.  `getSupportActionBar()` must be used until the minimum API >= 21.
        DrawerLayout drawerLayout = findViewById(R.id.drawerlayout);
        CoordinatorLayout coordinatorLayout = findViewById(R.id.coordinatorlayout);
        ActionBar actionBar = getSupportActionBar();

        // Apply the appropriate full screen mode the `SYSTEM_UI` flags.
        if (fullScreenBrowsingModeEnabled && inFullScreenBrowsingMode) {  // Privacy Browser is currently in full screen browsing mode.
            if (hideSystemBarsOnFullscreen) {  // Hide everything.
                // Remove the translucent navigation setting if it is currently flagged.
                getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);

                // Remove the translucent status bar overlay.
                getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);

                // Remove the translucent status bar overlay on the `Drawer Layout`, which is special and needs its own command.
                drawerLayout.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);

                /* SYSTEM_UI_FLAG_FULLSCREEN hides the status bar at the top of the screen.
                 * SYSTEM_UI_FLAG_HIDE_NAVIGATION hides the navigation bar on the bottom or right of the screen.
                 * SYSTEM_UI_FLAG_IMMERSIVE_STICKY makes the status and navigation bars translucent and automatically re-hides them after they are shown.
                 */
                coordinatorLayout.setSystemUiVisibility(View.SYSTEM_UI_FLAG_FULLSCREEN | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);
            } else {  // Hide everything except the status and navigation bars.
                // Remove any `SYSTEM_UI` flags from the coordinator layout.
                coordinatorLayout.setSystemUiVisibility(0);

                // Add the translucent status flag if it is unset.
                getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);

                if (translucentNavigationBarOnFullscreen) {
                    // Set the navigation bar to be translucent.
                    getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
                } else {
                    // Set the navigation bar to be black.
                    getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
                }
            }
        } else {  // Privacy Browser is not in full screen browsing mode.
            // Reset the full screen tracker, which could be true if Privacy Browser was in full screen mode before entering settings and full screen browsing was disabled.
            inFullScreenBrowsingMode = false;

            // Remove the incorrect lint warning below that the action bar might be null.
            assert actionBar != null;

            // Show the action bar if the find on page linear layout is not visible.
            if (findOnPageLinearLayout.getVisibility() == View.GONE) {
                actionBar.show();
            }

            // Show the `BannerAd` in the free flavor.
            if (BuildConfig.FLAVOR.contentEquals("free")) {
                // Initialize the ad.  The AdView is destroyed and recreated, which changes the ID, every time it is reloaded to handle possible rotations.
                AdHelper.initializeAds(findViewById(R.id.adview), getApplicationContext(), fragmentManager, getString(R.string.google_app_id), getString(R.string.ad_unit_id));
            }

            // Remove any `SYSTEM_UI` flags from the coordinator layout.
            coordinatorLayout.setSystemUiVisibility(0);

            // Remove the translucent navigation bar flag if it is set.
            getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);

            // Add the translucent status flag if it is unset.  This also resets `drawerLayout's` `View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN`.
            getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);

            // Constrain the coordinator layout inside the status and navigation bars.
            coordinatorLayout.setFitsSystemWindows(true);
        }
    }

    // `reloadWebsite` is used if returning from the Domains activity.  Otherwise JavaScript might not function correctly if it is newly enabled.
    // The deprecated `.getDrawable()` must be used until the minimum API >= 21.
    @SuppressWarnings("deprecation")
    private boolean applyDomainSettings(String url, boolean resetFavoriteIcon, boolean reloadWebsite) {
        // Get the current user agent.
        String initialUserAgent = mainWebView.getSettings().getUserAgentString();

        // Initialize a variable to track if the user agent changes.
        boolean userAgentChanged = false;

        // Parse the URL into a URI.
        Uri uri = Uri.parse(url);

        // Extract the domain from `uri`.
        String hostName = uri.getHost();

        // Initialize `loadingNewDomainName`.
        boolean loadingNewDomainName;

        // If either `hostName` or `currentDomainName` are `null`, run the options for loading a new domain name.
        // The lint suggestion to simplify the `if` statement is incorrect, because `hostName.equals(currentDomainName)` can produce a `null object reference.`
        //noinspection SimplifiableIfStatement
        if ((hostName == null) || (currentDomainName == null)) {
            loadingNewDomainName = true;
        } else {  // Determine if `hostName` equals `currentDomainName`.
            loadingNewDomainName = !hostName.equals(currentDomainName);
        }

        // Strings don't like to be null.
        if (hostName == null) {
            hostName = "";
        }

        // Only apply the domain settings if a new domain is being loaded.  This allows the user to set temporary settings for JavaScript, cookies, DOM storage, etc.
        if (loadingNewDomainName) {
            // Set the new `hostname` as the `currentDomainName`.
            currentDomainName = hostName;

            // Reset the ignoring of pinned domain information.
            ignorePinnedDomainInformation = false;

            // Reset the favorite icon if specified.
            if (resetFavoriteIcon) {
                favoriteIconBitmap = favoriteIconDefaultBitmap;
                favoriteIconImageView.setImageBitmap(Bitmap.createScaledBitmap(favoriteIconBitmap, 64, 64, true));
            }

            // Get a handle for the swipe refresh layout.
            SwipeRefreshLayout swipeRefreshLayout = findViewById(R.id.swiperefreshlayout);

            // Initialize the database handler.  The `0` specifies the database version, but that is ignored and set instead using a constant in `DomainsDatabaseHelper`.
            DomainsDatabaseHelper domainsDatabaseHelper = new DomainsDatabaseHelper(this, null, null, 0);

            // Get a full cursor from `domainsDatabaseHelper`.
            Cursor domainNameCursor = domainsDatabaseHelper.getDomainNameCursorOrderedByDomain();

            // Initialize `domainSettingsSet`.
            Set<String> domainSettingsSet = new HashSet<>();

            // Get the domain name column index.
            int domainNameColumnIndex = domainNameCursor.getColumnIndex(DomainsDatabaseHelper.DOMAIN_NAME);

            // Populate `domainSettingsSet`.
            for (int i = 0; i < domainNameCursor.getCount(); i++) {
                // Move `domainsCursor` to the current row.
                domainNameCursor.moveToPosition(i);

                // Store the domain name in `domainSettingsSet`.
                domainSettingsSet.add(domainNameCursor.getString(domainNameColumnIndex));
            }

            // Close `domainNameCursor.
            domainNameCursor.close();

            // Initialize variables to track if domain settings will be applied and, if so, under which name.
            domainSettingsApplied = false;
            String domainNameInDatabase = null;

            // Check the hostname.
            if (domainSettingsSet.contains(hostName)) {
                domainSettingsApplied = true;
                domainNameInDatabase = hostName;
            }

            // Check all the subdomains of the host name against wildcard domains in the domain cursor.
            while (!domainSettingsApplied && hostName.contains(".")) {  // Stop checking if domain settings are already applied or there are no more `.` in the host name.
                if (domainSettingsSet.contains("*." + hostName)) {  // Check the host name prepended by `*.`.
                    // Apply the domain settings.
                    domainSettingsApplied = true;

                    // Store the applied domain names as it appears in the database.
                    domainNameInDatabase = "*." + hostName;
                }

                // Strip out the lowest subdomain of of the host name.
                hostName = hostName.substring(hostName.indexOf(".") + 1);
            }


            // Get a handle for the shared preference.
            SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);

            // Store the general preference information.
            String defaultFontSizeString = sharedPreferences.getString("font_size", getString(R.string.font_size_default_value));
            String defaultUserAgentName = sharedPreferences.getString("user_agent", getString(R.string.user_agent_default_value));
            defaultCustomUserAgentString = sharedPreferences.getString("custom_user_agent", getString(R.string.custom_user_agent_default_value));
            boolean defaultSwipeToRefresh = sharedPreferences.getBoolean("swipe_to_refresh", true);
            nightMode = sharedPreferences.getBoolean("night_mode", false);
            boolean displayWebpageImages = sharedPreferences.getBoolean("display_webpage_images", true);

            if (domainSettingsApplied) {  // The url has custom domain settings.
                // Get a cursor for the current host and move it to the first position.
                Cursor currentHostDomainSettingsCursor = domainsDatabaseHelper.getCursorForDomainName(domainNameInDatabase);
                currentHostDomainSettingsCursor.moveToFirst();

                // Get the settings from the cursor.
                domainSettingsDatabaseId = (currentHostDomainSettingsCursor.getInt(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper._ID)));
                javaScriptEnabled = (currentHostDomainSettingsCursor.getInt(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.ENABLE_JAVASCRIPT)) == 1);
                firstPartyCookiesEnabled = (currentHostDomainSettingsCursor.getInt(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.ENABLE_FIRST_PARTY_COOKIES)) == 1);
                thirdPartyCookiesEnabled = (currentHostDomainSettingsCursor.getInt(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.ENABLE_THIRD_PARTY_COOKIES)) == 1);
                domStorageEnabled = (currentHostDomainSettingsCursor.getInt(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.ENABLE_DOM_STORAGE)) == 1);
                // Form data can be removed once the minimum API >= 26.
                saveFormDataEnabled = (currentHostDomainSettingsCursor.getInt(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.ENABLE_FORM_DATA)) == 1);
                easyListEnabled = (currentHostDomainSettingsCursor.getInt(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.ENABLE_EASYLIST)) == 1);
                easyPrivacyEnabled = (currentHostDomainSettingsCursor.getInt(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.ENABLE_EASYPRIVACY)) == 1);
                fanboysAnnoyanceListEnabled = (currentHostDomainSettingsCursor.getInt(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.ENABLE_FANBOYS_ANNOYANCE_LIST)) == 1);
                fanboysSocialBlockingListEnabled = (currentHostDomainSettingsCursor.getInt(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.ENABLE_FANBOYS_SOCIAL_BLOCKING_LIST)) == 1);
                ultraPrivacyEnabled = (currentHostDomainSettingsCursor.getInt(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.ENABLE_ULTRAPRIVACY)) == 1);
                blockAllThirdPartyRequests = (currentHostDomainSettingsCursor.getInt(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.BLOCK_ALL_THIRD_PARTY_REQUESTS)) == 1);
                String userAgentName = currentHostDomainSettingsCursor.getString(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.USER_AGENT));
                int fontSize = currentHostDomainSettingsCursor.getInt(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.FONT_SIZE));
                int swipeToRefreshInt = currentHostDomainSettingsCursor.getInt(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.SWIPE_TO_REFRESH));
                int nightModeInt = currentHostDomainSettingsCursor.getInt(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.NIGHT_MODE));
                int displayWebpageImagesInt = currentHostDomainSettingsCursor.getInt(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.DISPLAY_IMAGES));
                pinnedSslCertificate = (currentHostDomainSettingsCursor.getInt(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.PINNED_SSL_CERTIFICATE)) == 1);
                pinnedSslIssuedToCName = currentHostDomainSettingsCursor.getString(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.SSL_ISSUED_TO_COMMON_NAME));
                pinnedSslIssuedToOName = currentHostDomainSettingsCursor.getString(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.SSL_ISSUED_TO_ORGANIZATION));
                pinnedSslIssuedToUName = currentHostDomainSettingsCursor.getString(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.SSL_ISSUED_TO_ORGANIZATIONAL_UNIT));
                pinnedSslIssuedByCName = currentHostDomainSettingsCursor.getString(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.SSL_ISSUED_BY_COMMON_NAME));
                pinnedSslIssuedByOName = currentHostDomainSettingsCursor.getString(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.SSL_ISSUED_BY_ORGANIZATION));
                pinnedSslIssuedByUName = currentHostDomainSettingsCursor.getString(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.SSL_ISSUED_BY_ORGANIZATIONAL_UNIT));
                pinnedIpAddresses = (currentHostDomainSettingsCursor.getInt(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.PINNED_IP_ADDRESSES)) == 1);
                pinnedHostIpAddresses = currentHostDomainSettingsCursor.getString(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.IP_ADDRESSES));

                // Set `nightMode` according to `nightModeInt`.  If `nightModeInt` is `DomainsDatabaseHelper.NIGHT_MODE_SYSTEM_DEFAULT` the current setting from `sharedPreferences` will be used.
                switch (nightModeInt) {
                    case DomainsDatabaseHelper.NIGHT_MODE_ENABLED:
                        nightMode = true;
                        break;

                    case DomainsDatabaseHelper.NIGHT_MODE_DISABLED:
                        nightMode = false;
                        break;
                }

                // Store the domain JavaScript status.  This is used by the options menu night mode toggle.
                domainSettingsJavaScriptEnabled = javaScriptEnabled;

                // Enable JavaScript if night mode is enabled.
                if (nightMode) {
                    javaScriptEnabled = true;
                }

                // Set the pinned SSL certificate start date to `null` if the saved date `long` is 0.
                if (currentHostDomainSettingsCursor.getLong(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.SSL_START_DATE)) == 0) {
                    pinnedSslStartDate = null;
                } else {
                    pinnedSslStartDate = new Date(currentHostDomainSettingsCursor.getLong(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.SSL_START_DATE)));
                }

                // Set the pinned SSL certificate end date to `null` if the saved date `long` is 0.
                if (currentHostDomainSettingsCursor.getLong(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.SSL_END_DATE)) == 0) {
                    pinnedSslEndDate = null;
                } else {
                    pinnedSslEndDate = new Date(currentHostDomainSettingsCursor.getLong(currentHostDomainSettingsCursor.getColumnIndex(DomainsDatabaseHelper.SSL_END_DATE)));
                }

                // Close `currentHostDomainSettingsCursor`.
                currentHostDomainSettingsCursor.close();

                // Apply the domain settings.
                mainWebView.getSettings().setJavaScriptEnabled(javaScriptEnabled);
                cookieManager.setAcceptCookie(firstPartyCookiesEnabled);
                mainWebView.getSettings().setDomStorageEnabled(domStorageEnabled);

                // Apply the form data setting if the API < 26.
                if (Build.VERSION.SDK_INT < 26) {
                    mainWebView.getSettings().setSaveFormData(saveFormDataEnabled);
                }

                // Apply the font size.
                if (fontSize == 0) {  // Apply the default font size.
                    mainWebView.getSettings().setTextZoom(Integer.valueOf(defaultFontSizeString));
                } else {  // Apply the specified font size.
                    mainWebView.getSettings().setTextZoom(fontSize);
                }

                // Set third-party cookies status if API >= 21.
                if (Build.VERSION.SDK_INT >= 21) {
                    cookieManager.setAcceptThirdPartyCookies(mainWebView, thirdPartyCookiesEnabled);
                }

                // Only set the user agent if the webpage is not currently loading.  Otherwise, changing the user agent on redirects can cause the original website to reload.
                // <https://redmine.stoutner.com/issues/160>
                if (!urlIsLoading) {
                    // Set the user agent.
                    if (userAgentName.equals(getString(R.string.system_default_user_agent))) {  // Use the system default user agent.
                        // Get the array position of the default user agent name.
                        int defaultUserAgentArrayPosition = userAgentNamesArray.getPosition(defaultUserAgentName);

                        // Set the user agent according to the system default.
                        switch (defaultUserAgentArrayPosition) {
                            case UNRECOGNIZED_USER_AGENT:  // The default user agent name is not on the canonical list.
                                // This is probably because it was set in an older version of Privacy Browser before the switch to persistent user agent names.
                                mainWebView.getSettings().setUserAgentString(defaultUserAgentName);
                                break;

                            case SETTINGS_WEBVIEW_DEFAULT_USER_AGENT:
                                // Set the user agent to `""`, which uses the default value.
                                mainWebView.getSettings().setUserAgentString("");
                                break;

                            case SETTINGS_CUSTOM_USER_AGENT:
                                // Set the custom user agent.
                                mainWebView.getSettings().setUserAgentString(defaultCustomUserAgentString);
                                break;

                            default:
                                // Get the user agent string from the user agent data array
                                mainWebView.getSettings().setUserAgentString(userAgentDataArray[defaultUserAgentArrayPosition]);
                        }
                    } else {  // Set the user agent according to the stored name.
                        // Get the array position of the user agent name.
                        int userAgentArrayPosition = userAgentNamesArray.getPosition(userAgentName);

                        switch (userAgentArrayPosition) {
                            case UNRECOGNIZED_USER_AGENT:  // The user agent name contains a custom user agent.
                                mainWebView.getSettings().setUserAgentString(userAgentName);
                                break;

                            case SETTINGS_WEBVIEW_DEFAULT_USER_AGENT:
                                // Set the user agent to `""`, which uses the default value.
                                mainWebView.getSettings().setUserAgentString("");
                                break;

                            default:
                                // Get the user agent string from the user agent data array.
                                mainWebView.getSettings().setUserAgentString(userAgentDataArray[userAgentArrayPosition]);
                        }
                    }

                    // Store the applied user agent string, which is used in the View Source activity.
                    appliedUserAgentString = mainWebView.getSettings().getUserAgentString();

                    // Update the user agent change tracker.
                    userAgentChanged = !appliedUserAgentString.equals(initialUserAgent);
                }

                // Set swipe to refresh.
                switch (swipeToRefreshInt) {
                    case DomainsDatabaseHelper.SWIPE_TO_REFRESH_SYSTEM_DEFAULT:
                        // Set swipe to refresh according to the default.
                        swipeRefreshLayout.setEnabled(defaultSwipeToRefresh);
                        break;

                    case DomainsDatabaseHelper.SWIPE_TO_REFRESH_ENABLED:
                        // Enable swipe to refresh.
                        swipeRefreshLayout.setEnabled(true);
                        break;

                    case DomainsDatabaseHelper.SWIPE_TO_REFRESH_DISABLED:
                        // Disable swipe to refresh.
                        swipeRefreshLayout.setEnabled(false);
                }

                // Set the loading of webpage images.
                switch (displayWebpageImagesInt) {
                    case DomainsDatabaseHelper.DISPLAY_WEBPAGE_IMAGES_SYSTEM_DEFAULT:
                        mainWebView.getSettings().setLoadsImagesAutomatically(displayWebpageImages);
                        break;

                    case DomainsDatabaseHelper.DISPLAY_WEBPAGE_IMAGES_ENABLED:
                        mainWebView.getSettings().setLoadsImagesAutomatically(true);
                        break;

                    case DomainsDatabaseHelper.DISPLAY_WEBPAGE_IMAGES_DISABLED:
                        mainWebView.getSettings().setLoadsImagesAutomatically(false);
                        break;
                }

                // Set a green background on `urlTextBox` to indicate that custom domain settings are being used.  We have to use the deprecated `.getDrawable()` until the minimum API >= 21.
                if (darkTheme) {
                    urlAppBarRelativeLayout.setBackground(getResources().getDrawable(R.drawable.url_bar_background_dark_blue));
                } else {
                    urlAppBarRelativeLayout.setBackground(getResources().getDrawable(R.drawable.url_bar_background_light_green));
                }
            } else {  // The new URL does not have custom domain settings.  Load the defaults.
                // Store the values from `sharedPreferences` in variables.
                javaScriptEnabled = sharedPreferences.getBoolean("javascript", false);
                firstPartyCookiesEnabled = sharedPreferences.getBoolean("first_party_cookies", false);
                thirdPartyCookiesEnabled = sharedPreferences.getBoolean("third_party_cookies", false);
                domStorageEnabled = sharedPreferences.getBoolean("dom_storage", false);
                saveFormDataEnabled = sharedPreferences.getBoolean("save_form_data", false);  // Form data can be removed once the minimum API >= 26.
                easyListEnabled = sharedPreferences.getBoolean("easylist", true);
                easyPrivacyEnabled = sharedPreferences.getBoolean("easyprivacy", true);
                fanboysAnnoyanceListEnabled = sharedPreferences.getBoolean("fanboys_annoyance_list", true);
                fanboysSocialBlockingListEnabled = sharedPreferences.getBoolean("fanboys_social_blocking_list", true);
                ultraPrivacyEnabled = sharedPreferences.getBoolean("ultraprivacy", true);
                blockAllThirdPartyRequests = sharedPreferences.getBoolean("block_all_third_party_requests", false);

                // Set `javaScriptEnabled` to be `true` if `night_mode` is `true`.
                if (nightMode) {
                    javaScriptEnabled = true;
                }

                // Apply the default settings.
                mainWebView.getSettings().setJavaScriptEnabled(javaScriptEnabled);
                cookieManager.setAcceptCookie(firstPartyCookiesEnabled);
                mainWebView.getSettings().setDomStorageEnabled(domStorageEnabled);
                mainWebView.getSettings().setTextZoom(Integer.valueOf(defaultFontSizeString));
                swipeRefreshLayout.setEnabled(defaultSwipeToRefresh);

                // Apply the form data setting if the API < 26.
                if (Build.VERSION.SDK_INT < 26) {
                    mainWebView.getSettings().setSaveFormData(saveFormDataEnabled);
                }

                // Reset the pinned variables.
                domainSettingsDatabaseId = -1;
                pinnedSslCertificate = false;
                pinnedSslIssuedToCName = "";
                pinnedSslIssuedToOName = "";
                pinnedSslIssuedToUName = "";
                pinnedSslIssuedByCName = "";
                pinnedSslIssuedByOName = "";
                pinnedSslIssuedByUName = "";
                pinnedSslStartDate = null;
                pinnedSslEndDate = null;
                pinnedIpAddresses = false;
                pinnedHostIpAddresses = "";

                // Set third-party cookies status if API >= 21.
                if (Build.VERSION.SDK_INT >= 21) {
                    cookieManager.setAcceptThirdPartyCookies(mainWebView, thirdPartyCookiesEnabled);
                }

                // Only set the user agent if the webpage is not currently loading.  Otherwise, changing the user agent on redirects can cause the original website to reload.
                // <https://redmine.stoutner.com/issues/160>
                if (!urlIsLoading) {
                    // Get the array position of the user agent name.
                    int userAgentArrayPosition = userAgentNamesArray.getPosition(defaultUserAgentName);

                    // Set the user agent.
                    switch (userAgentArrayPosition) {
                        case UNRECOGNIZED_USER_AGENT:  // The default user agent name is not on the canonical list.
                            // This is probably because it was set in an older version of Privacy Browser before the switch to persistent user agent names.
                            mainWebView.getSettings().setUserAgentString(defaultUserAgentName);
                            break;

                        case SETTINGS_WEBVIEW_DEFAULT_USER_AGENT:
                            // Set the user agent to `""`, which uses the default value.
                            mainWebView.getSettings().setUserAgentString("");
                            break;

                        case SETTINGS_CUSTOM_USER_AGENT:
                            // Set the custom user agent.
                            mainWebView.getSettings().setUserAgentString(defaultCustomUserAgentString);
                            break;

                        default:
                            // Get the user agent string from the user agent data array
                            mainWebView.getSettings().setUserAgentString(userAgentDataArray[userAgentArrayPosition]);
                    }

                    // Store the applied user agent string, which is used in the View Source activity.
                    appliedUserAgentString = mainWebView.getSettings().getUserAgentString();

                    // Update the user agent change tracker.
                    userAgentChanged = !appliedUserAgentString.equals(initialUserAgent);
                }

                // Set the loading of webpage images.
                mainWebView.getSettings().setLoadsImagesAutomatically(displayWebpageImages);

                // Set a transparent background on `urlTextBox`.  The deprecated `.getDrawable()` must be used until the minimum API >= 21.
                urlAppBarRelativeLayout.setBackgroundDrawable(getResources().getDrawable(R.color.transparent));
            }

            // Close the domains database helper.
            domainsDatabaseHelper.close();

            // Update the privacy icons, but only if `mainMenu` has already been populated.
            if (mainMenu != null) {
                updatePrivacyIcons(true);
            }

            // TODO.
            swipeRefreshLayout.setEnabled(false);
        }

        // Reload the website if returning from the Domains activity.
        if (reloadWebsite) {
            mainWebView.reload();
        }

        // Return the user agent changed status.
        return userAgentChanged;
    }

    private void applyProxyThroughOrbot(boolean reloadWebsite) {
        // Get a handle for the shared preferences.
        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);

        // Get the search preferences.
        String homepageString = sharedPreferences.getString("homepage", getString(R.string.homepage_default_value));
        String torHomepageString = sharedPreferences.getString("tor_homepage", getString(R.string.tor_homepage_default_value));
        String torSearchString = sharedPreferences.getString("tor_search", getString(R.string.tor_search_default_value));
        String torSearchCustomUrlString = sharedPreferences.getString("tor_search_custom_url", getString(R.string.tor_search_custom_url_default_value));
        String searchString = sharedPreferences.getString("search", getString(R.string.search_default_value));
        String searchCustomUrlString = sharedPreferences.getString("search_custom_url", getString(R.string.search_custom_url_default_value));

        // Get a handle for the action bar.  `getSupportActionBar()` must be used until the minimum API >= 21.
        ActionBar actionBar = getSupportActionBar();

        // Remove the incorrect lint warning later that the action bar might be null.
        assert actionBar != null;

        // Set the homepage, search, and proxy options.
        if (proxyThroughOrbot) {  // Set the Tor options.
            // Set `torHomepageString` as `homepage`.
            homepage = torHomepageString;

            // If formattedUrlString is null assign the homepage to it.
            if (formattedUrlString == null) {
                formattedUrlString = homepage;
            }

            // Set the search URL.
            if (torSearchString.equals("Custom URL")) {  // Get the custom URL string.
                searchURL = torSearchCustomUrlString;
            } else {  // Use the string from the pre-built list.
                searchURL = torSearchString;
            }

            // Set the proxy.  `this` refers to the current activity where an `AlertDialog` might be displayed.
            OrbotProxyHelper.setProxy(getApplicationContext(), this, "localhost", "8118");

            // Set the `appBar` background to indicate proxying through Orbot is enabled.  `this` refers to the context.
            if (darkTheme) {
                actionBar.setBackgroundDrawable(ContextCompat.getDrawable(this, R.color.dark_blue_30));
            } else {
                actionBar.setBackgroundDrawable(ContextCompat.getDrawable(this, R.color.blue_50));
            }

            // Check to see if Orbot is ready.
            if (!orbotStatus.equals("ON")) {  // Orbot is not ready.
                // Set `waitingForOrbot`.
                waitingForOrbot = true;

                // Disable the wide view port so that the waiting for Orbot text is displayed correctly.
                mainWebView.getSettings().setUseWideViewPort(false);

                // Load a waiting page.  `null` specifies no encoding, which defaults to ASCII.
                mainWebView.loadData(waitingForOrbotHtmlString, "text/html", null);
            } else if (reloadWebsite) {  // Orbot is ready and the website should be reloaded.
                // Reload the website.
                mainWebView.reload();
            }
        } else {  // Set the non-Tor options.
            // Set `homepageString` as `homepage`.
            homepage = homepageString;

            // If formattedUrlString is null assign the homepage to it.
            if (formattedUrlString == null) {
                formattedUrlString = homepage;
            }

            // Set the search URL.
            if (searchString.equals("Custom URL")) {  // Get the custom URL string.
                searchURL = searchCustomUrlString;
            } else {  // Use the string from the pre-built list.
                searchURL = searchString;
            }

            // Reset the proxy to default.  The host is `""` and the port is `"0"`.
            OrbotProxyHelper.setProxy(getApplicationContext(), this, "", "0");

            // Set the default `appBar` background.  `this` refers to the context.
            if (darkTheme) {
                actionBar.setBackgroundDrawable(ContextCompat.getDrawable(this, R.color.gray_900));
            } else {
                actionBar.setBackgroundDrawable(ContextCompat.getDrawable(this, R.color.gray_100));
            }

            // Reset `waitingForOrbot.
            waitingForOrbot = false;

            // Reload the website if requested.
            if (reloadWebsite) {
                mainWebView.reload();
            }
        }
    }

    private void updatePrivacyIcons(boolean runInvalidateOptionsMenu) {
        // Get handles for the menu items.
        MenuItem privacyMenuItem = mainMenu.findItem(R.id.toggle_javascript);
        MenuItem firstPartyCookiesMenuItem = mainMenu.findItem(R.id.toggle_first_party_cookies);
        MenuItem domStorageMenuItem = mainMenu.findItem(R.id.toggle_dom_storage);
        MenuItem refreshMenuItem = mainMenu.findItem(R.id.refresh);

        // Update the privacy icon.
        if (javaScriptEnabled) {  // JavaScript is enabled.
            privacyMenuItem.setIcon(R.drawable.javascript_enabled);
        } else if (firstPartyCookiesEnabled) {  // JavaScript is disabled but cookies are enabled.
            privacyMenuItem.setIcon(R.drawable.warning);
        } else {  // All the dangerous features are disabled.
            privacyMenuItem.setIcon(R.drawable.privacy_mode);
        }

        // Update the first-party cookies icon.
        if (firstPartyCookiesEnabled) {  // First-party cookies are enabled.
            firstPartyCookiesMenuItem.setIcon(R.drawable.cookies_enabled);
        } else {  // First-party cookies are disabled.
            if (darkTheme) {
                firstPartyCookiesMenuItem.setIcon(R.drawable.cookies_disabled_dark);
            } else {
                firstPartyCookiesMenuItem.setIcon(R.drawable.cookies_disabled_light);
            }
        }

        // Update the DOM storage icon.
        if (javaScriptEnabled && domStorageEnabled) {  // Both JavaScript and DOM storage are enabled.
            domStorageMenuItem.setIcon(R.drawable.dom_storage_enabled);
        } else if (javaScriptEnabled) {  // JavaScript is enabled but DOM storage is disabled.
            if (darkTheme) {
                domStorageMenuItem.setIcon(R.drawable.dom_storage_disabled_dark);
            } else {
                domStorageMenuItem.setIcon(R.drawable.dom_storage_disabled_light);
            }
        } else {  // JavaScript is disabled, so DOM storage is ghosted.
            if (darkTheme) {
                domStorageMenuItem.setIcon(R.drawable.dom_storage_ghosted_dark);
            } else {
                domStorageMenuItem.setIcon(R.drawable.dom_storage_ghosted_light);
            }
        }

        // Update the refresh icon.
        if (darkTheme) {
            refreshMenuItem.setIcon(R.drawable.refresh_enabled_dark);
        } else {
            refreshMenuItem.setIcon(R.drawable.refresh_enabled_light);
        }

        // `invalidateOptionsMenu` calls `onPrepareOptionsMenu()` and redraws the icons in the `AppBar`.
        if (runInvalidateOptionsMenu) {
            invalidateOptionsMenu();
        }
    }

    private void openUrlWithExternalApp(String url) {
        // Create a download intent.  Not specifying the action type will display the maximum number of options.
        Intent downloadIntent = new Intent();

        // Set the URI and the MIME type.  Specifying `text/html` displays a good number of options.
        downloadIntent.setDataAndType(Uri.parse(url), "text/html");

        // Flag the intent to open in a new task.
        downloadIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

        // Show the chooser.
        startActivity(Intent.createChooser(downloadIntent, getString(R.string.open_with)));
    }

    private void highlightUrlText() {
        // Only highlight the URL text if the box is not currently selected.
        if (!urlTextBox.hasFocus()) {
            // Get the URL string.
            String urlString = urlTextBox.getText().toString();

            // Highlight the URL according to the protocol.
            if (urlString.startsWith("file://")) {  // This is a file URL.
                // De-emphasize only the protocol.
                urlTextBox.getText().setSpan(initialGrayColorSpan, 0, 7, Spanned.SPAN_INCLUSIVE_INCLUSIVE);
            } else if (urlString.startsWith("content://")) {
                // De-emphasize only the protocol.
                urlTextBox.getText().setSpan(initialGrayColorSpan, 0, 10, Spanned.SPAN_INCLUSIVE_INCLUSIVE);
            } else {  // This is a web URL.
                // Get the index of the `/` immediately after the domain name.
                int endOfDomainName = urlString.indexOf("/", (urlString.indexOf("//") + 2));

                // Create a base URL string.
                String baseUrl;

                // Get the base URL.
                if (endOfDomainName > 0) {  // There is at least one character after the base URL.
                    // Get the base URL.
                    baseUrl = urlString.substring(0, endOfDomainName);
                } else {  // There are no characters after the base URL.
                    // Set the base URL to be the entire URL string.
                    baseUrl = urlString;
                }

                // Get the index of the last `.` in the domain.
                int lastDotIndex = baseUrl.lastIndexOf(".");

                // Get the index of the penultimate `.` in the domain.
                int penultimateDotIndex = baseUrl.lastIndexOf(".", lastDotIndex - 1);

                // Markup the beginning of the URL.
                if (urlString.startsWith("http://")) {  // Highlight the protocol of connections that are not encrypted.
                    urlTextBox.getText().setSpan(redColorSpan, 0, 7, Spanned.SPAN_INCLUSIVE_INCLUSIVE);

                    // De-emphasize subdomains.
                    if (penultimateDotIndex > 0) {  // There is more than one subdomain in the domain name.
                        urlTextBox.getText().setSpan(initialGrayColorSpan, 7, penultimateDotIndex + 1, Spanned.SPAN_INCLUSIVE_INCLUSIVE);
                    }
                } else if (urlString.startsWith("https://")) {  // De-emphasize the protocol of connections that are encrypted.
                    if (penultimateDotIndex > 0) {  // There is more than one subdomain in the domain name.
                        // De-emphasize the protocol and the additional subdomains.
                        urlTextBox.getText().setSpan(initialGrayColorSpan, 0, penultimateDotIndex + 1, Spanned.SPAN_INCLUSIVE_INCLUSIVE);
                    } else {  // There is only one subdomain in the domain name.
                        // De-emphasize only the protocol.
                        urlTextBox.getText().setSpan(initialGrayColorSpan, 0, 8, Spanned.SPAN_INCLUSIVE_INCLUSIVE);
                    }
                }

                // De-emphasize the text after the domain name.
                if (endOfDomainName > 0) {
                    urlTextBox.getText().setSpan(finalGrayColorSpan, endOfDomainName, urlString.length(), Spanned.SPAN_INCLUSIVE_INCLUSIVE);
                }
            }
        }
    }

    private void loadBookmarksFolder() {
        // Update the bookmarks cursor with the contents of the bookmarks database for the current folder.
        bookmarksCursor = bookmarksDatabaseHelper.getBookmarksByDisplayOrder(currentBookmarksFolder);

        // Populate the bookmarks cursor adapter.  `this` specifies the `Context`.  `false` disables `autoRequery`.
        bookmarksCursorAdapter = new CursorAdapter(this, bookmarksCursor, false) {
            @Override
            public View newView(Context context, Cursor cursor, ViewGroup parent) {
                // Inflate the individual item layout.  `false` does not attach it to the root.
                return getLayoutInflater().inflate(R.layout.bookmarks_drawer_item_linearlayout, parent, false);
            }

            @Override
            public void bindView(View view, Context context, Cursor cursor) {
                // Get handles for the views.
                ImageView bookmarkFavoriteIcon = view.findViewById(R.id.bookmark_favorite_icon);
                TextView bookmarkNameTextView = view.findViewById(R.id.bookmark_name);

                // Get the favorite icon byte array from the cursor.
                byte[] favoriteIconByteArray = cursor.getBlob(cursor.getColumnIndex(BookmarksDatabaseHelper.FAVORITE_ICON));

                // Convert the byte array to a `Bitmap` beginning at the first byte and ending at the last.
                Bitmap favoriteIconBitmap = BitmapFactory.decodeByteArray(favoriteIconByteArray, 0, favoriteIconByteArray.length);

                // Display the bitmap in `bookmarkFavoriteIcon`.
                bookmarkFavoriteIcon.setImageBitmap(favoriteIconBitmap);

                // Get the bookmark name from the cursor and display it in `bookmarkNameTextView`.
                String bookmarkNameString = cursor.getString(cursor.getColumnIndex(BookmarksDatabaseHelper.BOOKMARK_NAME));
                bookmarkNameTextView.setText(bookmarkNameString);

                // Make the font bold for folders.
                if (cursor.getInt(cursor.getColumnIndex(BookmarksDatabaseHelper.IS_FOLDER)) == 1) {
                    bookmarkNameTextView.setTypeface(Typeface.DEFAULT_BOLD);
                } else {  // Reset the font to default for normal bookmarks.
                    bookmarkNameTextView.setTypeface(Typeface.DEFAULT);
                }
            }
        };

        // Populate the `ListView` with the adapter.
        bookmarksListView.setAdapter(bookmarksCursorAdapter);

        // Set the bookmarks drawer title.
        if (currentBookmarksFolder.isEmpty()) {
            bookmarksTitleTextView.setText(R.string.bookmarks);
        } else {
            bookmarksTitleTextView.setText(currentBookmarksFolder);
        }
    }

    private void openWithApp(String url) {
        // Create the open with intent with `ACTION_VIEW`.
        Intent openWithAppIntent = new Intent(Intent.ACTION_VIEW);

        // Set the URI but not the MIME type.  This should open all available apps.
        openWithAppIntent.setData(Uri.parse(url));

        // Flag the intent to open in a new task.
        openWithAppIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

        // Show the chooser.
        startActivity(openWithAppIntent);
    }

    private void openWithBrowser(String url) {
        // Create the open with intent with `ACTION_VIEW`.
        Intent openWithBrowserIntent = new Intent(Intent.ACTION_VIEW);

        // Set the URI and the MIME type.  `"text/html"` should load browser options.
        openWithBrowserIntent.setDataAndType(Uri.parse(url), "text/html");

        // Flag the intent to open in a new task.
        openWithBrowserIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

        // Show the chooser.
        startActivity(openWithBrowserIntent);
    }

    private static void checkPinnedMismatch() {
        if ((pinnedSslCertificate || pinnedIpAddresses) && !ignorePinnedDomainInformation) {
            // Initialize the current SSL certificate variables.
            String currentWebsiteIssuedToCName = "";
            String currentWebsiteIssuedToOName = "";
            String currentWebsiteIssuedToUName = "";
            String currentWebsiteIssuedByCName = "";
            String currentWebsiteIssuedByOName = "";
            String currentWebsiteIssuedByUName = "";
            Date currentWebsiteSslStartDate = null;
            Date currentWebsiteSslEndDate = null;


            // Extract the individual pieces of information from the current website SSL certificate if it is not null.
            if (sslCertificate != null) {
                currentWebsiteIssuedToCName = sslCertificate.getIssuedTo().getCName();
                currentWebsiteIssuedToOName = sslCertificate.getIssuedTo().getOName();
                currentWebsiteIssuedToUName = sslCertificate.getIssuedTo().getUName();
                currentWebsiteIssuedByCName = sslCertificate.getIssuedBy().getCName();
                currentWebsiteIssuedByOName = sslCertificate.getIssuedBy().getOName();
                currentWebsiteIssuedByUName = sslCertificate.getIssuedBy().getUName();
                currentWebsiteSslStartDate = sslCertificate.getValidNotBeforeDate();
                currentWebsiteSslEndDate = sslCertificate.getValidNotAfterDate();
            }

            // Initialize string variables to store the SSL certificate dates.  Strings are needed to compare the values below, which doesn't work with `Dates` if they are `null`.
            String currentWebsiteSslStartDateString = "";
            String currentWebsiteSslEndDateString = "";
            String pinnedSslStartDateString = "";
            String pinnedSslEndDateString = "";

            // Convert the `Dates` to `Strings` if they are not `null`.
            if (currentWebsiteSslStartDate != null) {
                currentWebsiteSslStartDateString = currentWebsiteSslStartDate.toString();
            }

            if (currentWebsiteSslEndDate != null) {
                currentWebsiteSslEndDateString = currentWebsiteSslEndDate.toString();
            }

            if (pinnedSslStartDate != null) {
                pinnedSslStartDateString = pinnedSslStartDate.toString();
            }

            if (pinnedSslEndDate != null) {
                pinnedSslEndDateString = pinnedSslEndDate.toString();
            }

            // Check to see if the pinned information matches the current information.
            if ((pinnedIpAddresses && !currentHostIpAddresses.equals(pinnedHostIpAddresses)) || (pinnedSslCertificate && (!currentWebsiteIssuedToCName.equals(pinnedSslIssuedToCName) ||
                    !currentWebsiteIssuedToOName.equals(pinnedSslIssuedToOName) || !currentWebsiteIssuedToUName.equals(pinnedSslIssuedToUName) ||
                    !currentWebsiteIssuedByCName.equals(pinnedSslIssuedByCName) || !currentWebsiteIssuedByOName.equals(pinnedSslIssuedByOName) ||
                    !currentWebsiteIssuedByUName.equals(pinnedSslIssuedByUName) || !currentWebsiteSslStartDateString.equals(pinnedSslStartDateString) ||
                    !currentWebsiteSslEndDateString.equals(pinnedSslEndDateString)))) {

                // Get a handle for the pinned mismatch alert dialog.
                DialogFragment pinnedMismatchDialogFragment = PinnedMismatchDialog.displayDialog(pinnedSslCertificate, pinnedIpAddresses);

                // Show the pinned mismatch alert dialog.
                pinnedMismatchDialogFragment.show(fragmentManager, "Pinned Mismatch");
            }
        }
    }

    // This must run asynchronously because it involves a network request.  `String` declares the parameters.  `Void` does not declare progress units.  `String` contains the results.
    private static class GetHostIpAddresses extends AsyncTask<String, Void, String> {
        // The weak references are used to determine if the activity have disappeared while the AsyncTask is running.
        private final WeakReference<Activity> activityWeakReference;

        GetHostIpAddresses(Activity activity) {
            // Populate the weak references.
            activityWeakReference = new WeakReference<>(activity);
        }

        // `onPreExecute()` operates on the UI thread.
        @Override
        protected void onPreExecute() {
            // Get a handle for the activity.
            Activity activity = activityWeakReference.get();

            // Abort if the activity is gone.
            if ((activity == null) || activity.isFinishing()) {
                return;
            }

            // Set the getting IP addresses tracker.
            gettingIpAddresses = true;
        }


        @Override
        protected String doInBackground(String... domainName) {
            // Get a handle for the activity.
            Activity activity = activityWeakReference.get();

            // Abort if the activity is gone.
            if ((activity == null) || activity.isFinishing()) {
                // Return an empty spannable string builder.
                return "";
            }

            // Initialize an IP address string builder.
            StringBuilder ipAddresses = new StringBuilder();

            // Get an array with the IP addresses for the host.
            try {
                // Get an array with all the IP addresses for the domain.
                InetAddress[] inetAddressesArray = InetAddress.getAllByName(domainName[0]);

                // Add each IP address to the string builder.
                for (InetAddress inetAddress : inetAddressesArray) {
                    if (ipAddresses.length() == 0) {  // This is the first IP address.
                        // Add the IP address to the string builder.
                        ipAddresses.append(inetAddress.getHostAddress());
                    } else {  // This is not the first IP address.
                        // Add a line break to the string builder first.
                        ipAddresses.append("\n");

                        // Add the IP address to the string builder.
                        ipAddresses.append(inetAddress.getHostAddress());
                    }
                }
            } catch (UnknownHostException exception) {
                // Do nothing.
            }

            // Return the string.
            return ipAddresses.toString();
        }

        // `onPostExecute()` operates on the UI thread.
        @Override
        protected void onPostExecute(String ipAddresses) {
            // Get a handle for the activity.
            Activity activity = activityWeakReference.get();

            // Abort if the activity is gone.
            if ((activity == null) || activity.isFinishing()) {
                return;
            }

            // Store the IP addresses.
            currentHostIpAddresses = ipAddresses;

            if (!urlIsLoading) {
                checkPinnedMismatch();
            }

            // Reset the getting IP addresses tracker.
            gettingIpAddresses = false;
        }
    }
}