Migrate five dialogs to Kotlin. https://redmine.stoutner.com/issues/604
[PrivacyBrowser.git] / app / src / main / java / com / stoutner / privacybrowser / dialogs / SslCertificateErrorDialog.java
index 8bde8de0f198e978bf58ca8b760e32ff12903b8c..76a23a815420101b0564c473b9818b4ee694878d 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2016-2018 Soren Stoutner <soren@stoutner.com>.
+ * Copyright © 2016-2020 Soren Stoutner <soren@stoutner.com>.
  *
  * This file is part of Privacy Browser <https://www.stoutner.com/privacy-browser>.
  *
 package com.stoutner.privacybrowser.dialogs;
 
 import android.annotation.SuppressLint;
-import android.app.AlertDialog;
+import android.app.Activity;
 import android.app.Dialog;
-import android.content.Context;
 import android.content.DialogInterface;
+import android.content.SharedPreferences;
+import android.content.res.Configuration;
+import android.net.Uri;
 import android.net.http.SslCertificate;
 import android.net.http.SslError;
+import android.os.AsyncTask;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-// `AppCompatDialogFragment` is used instead of `DialogFragment` to avoid an error on API <=22.
-import android.support.v7.app.AppCompatDialogFragment;
+import android.preference.PreferenceManager;
 import android.text.SpannableStringBuilder;
 import android.text.Spanned;
 import android.text.style.ForegroundColorSpan;
 import android.view.LayoutInflater;
+import android.view.View;
 import android.view.WindowManager;
+import android.webkit.SslErrorHandler;
 import android.widget.TextView;
 
+import androidx.annotation.NonNull;
+import androidx.appcompat.app.AlertDialog;
+import androidx.fragment.app.DialogFragment;
+
 import com.stoutner.privacybrowser.R;
 import com.stoutner.privacybrowser.activities.MainWebViewActivity;
+import com.stoutner.privacybrowser.fragments.WebViewTabFragment;
+import com.stoutner.privacybrowser.views.NestedScrollWebView;
 
+import java.lang.ref.WeakReference;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
 import java.text.DateFormat;
 import java.util.Date;
 
-public class SslCertificateErrorDialog extends AppCompatDialogFragment {
-
-    // The private variables are used in `onCreate()` and `onCreateDialog()`.
-    private int primaryErrorInt;
-    private String urlWithError;
-    private String issuedToCName;
-    private String issuedToOName;
-    private String issuedToUName;
-    private String issuedByCName;
-    private String issuedByOName;
-    private String issuedByUName;
-    private String startDate;
-    private String endDate;
-
-    public static SslCertificateErrorDialog displayDialog(SslError error) {
+public class SslCertificateErrorDialog extends DialogFragment {
+    public static SslCertificateErrorDialog displayDialog(SslError error, long webViewFragmentId) {
         // Get the various components of the SSL error message.
         int primaryErrorIntForBundle = error.getPrimaryError();
         String urlWithErrorForBundle = error.getUrl();
@@ -71,94 +70,88 @@ public class SslCertificateErrorDialog extends AppCompatDialogFragment {
         Date startDateForBundle = sslCertificate.getValidNotBeforeDate();
         Date endDateForBundle = sslCertificate.getValidNotAfterDate();
 
-        // Store the SSL error message components in a `Bundle`.
+        // Create an arguments bundle.
         Bundle argumentsBundle = new Bundle();
-        argumentsBundle.putInt("PrimaryErrorInt", primaryErrorIntForBundle);
-        argumentsBundle.putString("UrlWithError", urlWithErrorForBundle);
-        argumentsBundle.putString("IssuedToCName", issuedToCNameForBundle);
-        argumentsBundle.putString("IssuedToOName", issuedToONameForBundle);
-        argumentsBundle.putString("IssuedToUName", issuedToUNameForBundle);
-        argumentsBundle.putString("IssuedByCName", issuedByCNameForBundle);
-        argumentsBundle.putString("IssuedByOName", issuedByONameForBundle);
-        argumentsBundle.putString("IssuedByUName", issuedByUNameForBundle);
-        argumentsBundle.putString("StartDate", DateFormat.getDateTimeInstance(DateFormat.MEDIUM, DateFormat.LONG).format(startDateForBundle));
-        argumentsBundle.putString("EndDate", DateFormat.getDateTimeInstance(DateFormat.MEDIUM, DateFormat.LONG).format(endDateForBundle));
-
-        // Add `argumentsBundle` to this instance of `SslCertificateErrorDialog`.
+
+        // Store the SSL error message components in a `Bundle`.
+        argumentsBundle.putInt("primary_error_int", primaryErrorIntForBundle);
+        argumentsBundle.putString("url_with_error", urlWithErrorForBundle);
+        argumentsBundle.putString("issued_to_cname", issuedToCNameForBundle);
+        argumentsBundle.putString("issued_to_oname", issuedToONameForBundle);
+        argumentsBundle.putString("issued_to_uname", issuedToUNameForBundle);
+        argumentsBundle.putString("issued_by_cname", issuedByCNameForBundle);
+        argumentsBundle.putString("issued_by_oname", issuedByONameForBundle);
+        argumentsBundle.putString("issued_by_uname", issuedByUNameForBundle);
+        argumentsBundle.putString("start_date", DateFormat.getDateTimeInstance(DateFormat.MEDIUM, DateFormat.LONG).format(startDateForBundle));
+        argumentsBundle.putString("end_date", DateFormat.getDateTimeInstance(DateFormat.MEDIUM, DateFormat.LONG).format(endDateForBundle));
+        argumentsBundle.putLong("webview_fragment_id", webViewFragmentId);
+
+        // Create a new instance of the SSL certificate error dialog.
         SslCertificateErrorDialog thisSslCertificateErrorDialog = new SslCertificateErrorDialog();
+
+        // Add the arguments bundle to the new dialog.
         thisSslCertificateErrorDialog.setArguments(argumentsBundle);
+
+        // Return the new dialog.
         return thisSslCertificateErrorDialog;
     }
 
+    // `@SuppressLint("InflateParams")` removes the warning about using `null` as the parent view group when inflating the `AlertDialog`.
+    @SuppressLint("InflateParams")
     @Override
-    public void onCreate(Bundle savedInstanceState) {
-        super.onCreate(savedInstanceState);
-
-        // Remove the incorrect lint warning that `getArguments()` might be null.
-        assert getArguments() != null;
-
-        // Save the components of the SSL error message in class variables.
-        primaryErrorInt = getArguments().getInt("PrimaryErrorInt");
-        urlWithError = getArguments().getString("UrlWithError");
-        issuedToCName = getArguments().getString("IssuedToCName");
-        issuedToOName = getArguments().getString("IssuedToOName");
-        issuedToUName = getArguments().getString("IssuedToUName");
-        issuedByCName = getArguments().getString("IssuedByCName");
-        issuedByOName = getArguments().getString("IssuedByOName");
-        issuedByUName = getArguments().getString("IssuedByUName");
-        startDate = getArguments().getString("StartDate");
-        endDate = getArguments().getString("EndDate");
-    }
+    @NonNull
+    public Dialog onCreateDialog(Bundle savedInstanceState) {
+        // Get a handle for the arguments.
+        Bundle arguments = getArguments();
 
-    // The public interface is used to send information back to the parent activity.
-    public interface SslCertificateErrorListener {
-        void onSslErrorCancel();
+        // Remove the incorrect lint warning that the arguments might be null.
+        assert arguments != null;
 
-        void onSslErrorProceed();
-    }
+        // Get the variables from the bundle.
+        int primaryErrorInt = arguments.getInt("primary_error_int");
+        String urlWithErrors = arguments.getString("url_with_error");
+        String issuedToCName = arguments.getString("issued_to_cname");
+        String issuedToOName = arguments.getString("issued_to_oname");
+        String issuedToUName = arguments.getString("issued_to_uname");
+        String issuedByCName = arguments.getString("issued_by_cname");
+        String issuedByOName = arguments.getString("issued_by_oname");
+        String issuedByUName = arguments.getString("issued_by_uname");
+        String startDate = arguments.getString("start_date");
+        String endDate = arguments.getString("end_date");
+        long webViewFragmentId = arguments.getLong("webview_fragment_id");
 
-    // `sslCertificateErrorListener` is used in `onAttach` and `onCreateDialog`.
-    private SslCertificateErrorListener sslCertificateErrorListener;
+        // Get the current position of this WebView fragment.
+        int webViewPosition = MainWebViewActivity.webViewPagerAdapter.getPositionForId(webViewFragmentId);
 
-    // Check to make sure that the parent activity implements the listener.
-    public void onAttach(Context context) {
-        super.onAttach(context);
+        // Get the WebView tab fragment.
+        WebViewTabFragment webViewTabFragment = MainWebViewActivity.webViewPagerAdapter.getPageFragment(webViewPosition);
 
-        try {
-            sslCertificateErrorListener = (SslCertificateErrorListener) context;
-        } catch(ClassCastException exception) {
-            throw new ClassCastException(context.toString() + " must implement SslCertificateErrorListener");
-        }
-    }
+        // Get the fragment view.
+        View fragmentView = webViewTabFragment.getView();
 
-    // `@SuppressLing("InflateParams")` removes the warning about using `null` as the parent view group when inflating the `AlertDialog`.
-    @SuppressLint("InflateParams")
-    @SuppressWarnings("deprecation")
-    @Override
-    @NonNull
-    public Dialog onCreateDialog(Bundle savedInstanceState) {
-        // Remove the incorrect lint warning that `getActivity()` might be null.
-        assert getActivity() != null;
+        // Remove the incorrect lint warning below that the fragment view might be null.
+        assert fragmentView != null;
+
+        // Get a handle for the current WebView.
+        NestedScrollWebView nestedScrollWebView = fragmentView.findViewById(R.id.nestedscroll_webview);
+
+        // Get a handle for the SSL error handler.
+        SslErrorHandler sslErrorHandler = nestedScrollWebView.getSslErrorHandler();
 
         // Get the activity's layout inflater.
-        LayoutInflater layoutInflater = getActivity().getLayoutInflater();
+        LayoutInflater layoutInflater = requireActivity().getLayoutInflater();
 
         // Use an alert dialog builder to create the alert dialog.
-        AlertDialog.Builder dialogBuilder;
+        AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(requireContext(), R.style.PrivacyBrowserAlertDialog);
 
-        // Set the style and icon according to the theme.
-        if (MainWebViewActivity.darkTheme) {
-            // Set the style.
-            dialogBuilder = new AlertDialog.Builder(getActivity(), R.style.PrivacyBrowserAlertDialogDark);
+        // Get the current theme status.
+        int currentThemeStatus = getResources().getConfiguration().uiMode & Configuration.UI_MODE_NIGHT_MASK;
 
-            // Set the icon.
-            dialogBuilder.setIcon(R.drawable.ssl_certificate_enabled_dark);
+        // Set the icon according to the theme.
+        if (currentThemeStatus == Configuration.UI_MODE_NIGHT_YES) {
+            dialogBuilder.setIcon(R.drawable.ssl_certificate_enabled_night);
         } else {
-            // Set the style.
-            dialogBuilder = new AlertDialog.Builder(getActivity(), R.style.PrivacyBrowserAlertDialogLight);
-
-            // Set the icon.
-            dialogBuilder.setIcon(R.drawable.ssl_certificate_enabled_light);
+            dialogBuilder.setIcon(R.drawable.ssl_certificate_enabled_day);
         }
 
         // Set the title.
@@ -167,18 +160,42 @@ public class SslCertificateErrorDialog extends AppCompatDialogFragment {
         // Set the view.  The parent view is `null` because it will be assigned by `AlertDialog`.
         dialogBuilder.setView(layoutInflater.inflate(R.layout.ssl_certificate_error, null));
 
-        // Set a listener on the negative button.
-        dialogBuilder.setNegativeButton(R.string.cancel, (DialogInterface dialog, int which) -> sslCertificateErrorListener.onSslErrorCancel());
+        // Set a listener on the cancel button.
+        dialogBuilder.setNegativeButton(R.string.cancel, (DialogInterface dialog, int which) -> {
+            // Check to make sure the SSL error handler is not null.  This might happen if multiple dialogs are displayed at once.
+            if (sslErrorHandler != null) {
+                // Cancel the request.
+                sslErrorHandler.cancel();
+
+                // Reset the SSL error handler.
+                nestedScrollWebView.resetSslErrorHandler();
+            }
+        });
 
-        // Set a listener on the positive button.
-        dialogBuilder.setPositiveButton(R.string.proceed, (DialogInterface dialog, int which) -> sslCertificateErrorListener.onSslErrorProceed());
+        // Set a listener on the proceed button.
+        dialogBuilder.setPositiveButton(R.string.proceed, (DialogInterface dialog, int which) -> {
+            // Check to make sure the SSL error handler is not null.  This might happen if multiple dialogs are displayed at once.
+            if (sslErrorHandler != null) {
+                // Cancel the request.
+                sslErrorHandler.proceed();
+
+                // Reset the SSL error handler.
+                nestedScrollWebView.resetSslErrorHandler();
+            }
+        });
 
 
         // Create an alert dialog from the alert dialog builder.
         AlertDialog alertDialog = dialogBuilder.create();
 
+        // Get a handle for the shared preferences.
+        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getContext());
+
+        // Get the screenshot preference.
+        boolean allowScreenshots = sharedPreferences.getBoolean("allow_screenshots", false);
+
         // Disable screenshots if not allowed.
-        if (!MainWebViewActivity.allowScreenshots) {
+        if (!allowScreenshots) {
             // Remove the warning below that `getWindow()` might be null.
             assert alertDialog.getWindow() != null;
 
@@ -186,22 +203,42 @@ public class SslCertificateErrorDialog extends AppCompatDialogFragment {
             alertDialog.getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE);
         }
 
-        // We have to show the alert dialog before we can modify the content.
+        // Get a URI for the URL with errors.
+        Uri uriWithErrors = Uri.parse(urlWithErrors);
+
+        // Get the IP addresses for the URI.
+        new GetIpAddresses(getActivity(), alertDialog).execute(uriWithErrors.getHost());
+
+        // The alert dialog must be shown before the contents can be modified.
         alertDialog.show();
 
         // Get handles for the `TextViews`
         TextView primaryErrorTextView = alertDialog.findViewById(R.id.primary_error);
-        TextView urlTextView = alertDialog.findViewById(R.id.url_error_dialog);
-        TextView issuedToCNameTextView = alertDialog.findViewById(R.id.issued_to_cname_error_dialog);
-        TextView issuedToONameTextView = alertDialog.findViewById(R.id.issued_to_oname_error_dialog);
-        TextView issuedToUNameTextView = alertDialog.findViewById(R.id.issued_to_uname_error_dialog);
+        TextView urlTextView = alertDialog.findViewById(R.id.url);
+        TextView issuedToCNameTextView = alertDialog.findViewById(R.id.issued_to_cname);
+        TextView issuedToONameTextView = alertDialog.findViewById(R.id.issued_to_oname);
+        TextView issuedToUNameTextView = alertDialog.findViewById(R.id.issued_to_uname);
         TextView issuedByTextView = alertDialog.findViewById(R.id.issued_by_textview);
-        TextView issuedByCNameTextView = alertDialog.findViewById(R.id.issued_by_cname_error_dialog);
-        TextView issuedByONameTextView = alertDialog.findViewById(R.id.issued_by_oname_error_dialog);
-        TextView issuedByUNameTextView = alertDialog.findViewById(R.id.issued_by_uname_error_dialog);
+        TextView issuedByCNameTextView = alertDialog.findViewById(R.id.issued_by_cname);
+        TextView issuedByONameTextView = alertDialog.findViewById(R.id.issued_by_oname);
+        TextView issuedByUNameTextView = alertDialog.findViewById(R.id.issued_by_uname);
         TextView validDatesTextView = alertDialog.findViewById(R.id.valid_dates_textview);
-        TextView startDateTextView = alertDialog.findViewById(R.id.start_date_error_dialog);
-        TextView endDateTextView = alertDialog.findViewById(R.id.end_date_error_dialog);
+        TextView startDateTextView = alertDialog.findViewById(R.id.start_date);
+        TextView endDateTextView = alertDialog.findViewById(R.id.end_date);
+
+        // Remove the incorrect lint warnings below that the views might be null.
+        assert primaryErrorTextView != null;
+        assert urlTextView != null;
+        assert issuedToCNameTextView != null;
+        assert issuedToONameTextView != null;
+        assert issuedToUNameTextView != null;
+        assert issuedByTextView != null;
+        assert issuedByCNameTextView != null;
+        assert issuedByONameTextView != null;
+        assert issuedByUNameTextView != null;
+        assert validDatesTextView != null;
+        assert startDateTextView != null;
+        assert endDateTextView != null;
 
         // Setup the common strings.
         String urlLabel = getString(R.string.url_label) + "  ";
@@ -211,8 +248,8 @@ public class SslCertificateErrorDialog extends AppCompatDialogFragment {
         String startDateLabel = getString(R.string.start_date) + "  ";
         String endDateLabel = getString(R.string.end_date) + "  ";
 
-        // Create a `SpannableStringBuilder` for each `TextView` that needs multiple colors of text.
-        SpannableStringBuilder urlStringBuilder = new SpannableStringBuilder(urlLabel + urlWithError);
+        // Create a spannable string builder for each text view that needs multiple colors of text.
+        SpannableStringBuilder urlStringBuilder = new SpannableStringBuilder(urlLabel + urlWithErrors);
         SpannableStringBuilder issuedToCNameStringBuilder = new SpannableStringBuilder(cNameLabel + issuedToCName);
         SpannableStringBuilder issuedToONameStringBuilder = new SpannableStringBuilder(oNameLabel + issuedToOName);
         SpannableStringBuilder issuedToUNameStringBuilder = new SpannableStringBuilder(uNameLabel + issuedToUName);
@@ -222,19 +259,17 @@ public class SslCertificateErrorDialog extends AppCompatDialogFragment {
         SpannableStringBuilder startDateStringBuilder = new SpannableStringBuilder(startDateLabel + startDate);
         SpannableStringBuilder endDateStringBuilder = new SpannableStringBuilder((endDateLabel + endDate));
 
-        // Create a red `ForegroundColorSpan`.  We have to use the deprecated `getColor` until API >= 23.
-        @SuppressWarnings("deprecation") ForegroundColorSpan redColorSpan = new ForegroundColorSpan(getResources().getColor(R.color.red_a700));
-
-        // Create a blue `ForegroundColorSpan`.
+        // Define the color spans.
         ForegroundColorSpan blueColorSpan;
+        ForegroundColorSpan redColorSpan;
 
-        // Set `blueColorSpan` according to the theme.  We have to use the deprecated `getColor()` until API >= 23.
-        if (MainWebViewActivity.darkTheme) {
-            //noinspection deprecation
-            blueColorSpan = new ForegroundColorSpan(getResources().getColor(R.color.blue_400));
-        } else {
-            //noinspection deprecation
+        // Set the color spans according to the theme.  The deprecated `getResources()` must be used until the minimum API >= 23.
+        if (currentThemeStatus == Configuration.UI_MODE_NIGHT_NO) {
             blueColorSpan = new ForegroundColorSpan(getResources().getColor(R.color.blue_700));
+            redColorSpan = new ForegroundColorSpan(getResources().getColor(R.color.red_a700));
+        } else {
+            blueColorSpan = new ForegroundColorSpan(getResources().getColor(R.color.violet_500));
+            redColorSpan = new ForegroundColorSpan(getResources().getColor(R.color.red_900));
         }
 
         // Setup the spans to display the certificate information in blue.  `SPAN_INCLUSIVE_INCLUSIVE` allows the span to grow in either direction.
@@ -263,8 +298,12 @@ public class SslCertificateErrorDialog extends AppCompatDialogFragment {
                 break;
 
             case SslError.SSL_UNTRUSTED:
-                // Change the `issuesByTextView` text to red.  We have to use the deprecated `getColor()` until API >= 23.
-                issuedByTextView.setTextColor(getResources().getColor(R.color.red_a700));
+                // Change the issued by text view text to red.  The deprecated `getResources().getColor` must be used until the minimum API >= 23.
+                if (currentThemeStatus == Configuration.UI_MODE_NIGHT_YES) {
+                    issuedByTextView.setTextColor(getResources().getColor(R.color.red_900));
+                } else {
+                    issuedByTextView.setTextColor(getResources().getColor(R.color.red_a700));
+                }
 
                 // Change the issued by span color to red.
                 issuedByCNameStringBuilder.setSpan(redColorSpan, cNameLabel.length(), issuedByCNameStringBuilder.length(), Spanned.SPAN_INCLUSIVE_INCLUSIVE);
@@ -276,8 +315,12 @@ public class SslCertificateErrorDialog extends AppCompatDialogFragment {
                 break;
 
             case SslError.SSL_DATE_INVALID:
-                // Change the `validDatesTextView` text to red.  We have to use the deprecated `getColor()` until API >= 23.
-                validDatesTextView.setTextColor(getResources().getColor(R.color.red_a700));
+                // Change the valid dates text view text to red.  The deprecated `getResources().getColor` must be used until the minimum API >= 23.
+                if (currentThemeStatus == Configuration.UI_MODE_NIGHT_YES) {
+                    validDatesTextView.setTextColor(getResources().getColor(R.color.red_900));
+                } else {
+                    validDatesTextView.setTextColor(getResources().getColor(R.color.red_a700));
+                }
 
                 // Change the date span colors to red.
                 startDateStringBuilder.setSpan(redColorSpan, startDateLabel.length(), startDateStringBuilder.length(), Spanned.SPAN_INCLUSIVE_INCLUSIVE);
@@ -322,7 +365,103 @@ public class SslCertificateErrorDialog extends AppCompatDialogFragment {
         startDateTextView.setText(startDateStringBuilder);
         endDateTextView.setText(endDateStringBuilder);
 
-        // `onCreateDialog` requires the return of an `AlertDialog`.
+        // `onCreateDialog` requires the return of an alert dialog.
         return alertDialog;
     }
+
+
+    // This must run asynchronously because it involves a network request.  `String` declares the parameters.  `Void` does not declare progress units.  `SpannableStringBuilder` contains the results.
+    private static class GetIpAddresses extends AsyncTask<String, Void, SpannableStringBuilder> {
+        // The weak references are used to determine if the activity or the alert dialog have disappeared while the AsyncTask is running.
+        private WeakReference<Activity> activityWeakReference;
+        private WeakReference<AlertDialog> alertDialogWeakReference;
+
+        GetIpAddresses(Activity activity, AlertDialog alertDialog) {
+            // Populate the weak references.
+            activityWeakReference = new WeakReference<>(activity);
+            alertDialogWeakReference = new WeakReference<>(alertDialog);
+        }
+
+        @Override
+        protected SpannableStringBuilder doInBackground(String... domainName) {
+            // Get handles for the activity and the alert dialog.
+            Activity activity = activityWeakReference.get();
+            AlertDialog alertDialog = alertDialogWeakReference.get();
+
+            // Abort if the activity or the dialog is gone.
+            if ((activity == null) || (activity.isFinishing()) || (alertDialog == null)) {
+                return new SpannableStringBuilder();
+            }
+
+            // 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) {
+                    // Check to see if this is not the first IP address.
+                    if (ipAddresses.length() > 0) {
+                        // 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.
+            }
+
+            // Set the label.
+            String ipAddressesLabel = activity.getString(R.string.ip_addresses) + "  ";
+
+            // Create a spannable string builder.
+            SpannableStringBuilder ipAddressesStringBuilder = new SpannableStringBuilder(ipAddressesLabel + ipAddresses);
+
+            // Create a blue foreground color span.
+            ForegroundColorSpan blueColorSpan;
+
+            // Get the current theme status.
+            int currentThemeStatus = activity.getResources().getConfiguration().uiMode & Configuration.UI_MODE_NIGHT_MASK;
+
+            // Set the blue color span according to the theme.  The deprecated `getColor()` must be used until the minimum API >= 23.
+            if (currentThemeStatus == Configuration.UI_MODE_NIGHT_YES) {
+                blueColorSpan = new ForegroundColorSpan(activity.getResources().getColor(R.color.violet_500));
+            } else {
+                blueColorSpan = new ForegroundColorSpan(activity.getResources().getColor(R.color.blue_700));
+            }
+
+            // Set the string builder to display the certificate information in blue.  `SPAN_INCLUSIVE_INCLUSIVE` allows the span to grow in either direction.
+            ipAddressesStringBuilder.setSpan(blueColorSpan, ipAddressesLabel.length(), ipAddressesStringBuilder.length(), Spanned.SPAN_INCLUSIVE_INCLUSIVE);
+
+            // Return the formatted string.
+            return ipAddressesStringBuilder;
+        }
+
+        // `onPostExecute()` operates on the UI thread.
+        @Override
+        protected void onPostExecute(SpannableStringBuilder ipAddresses) {
+            // Get handles for the activity and the alert dialog.
+            Activity activity = activityWeakReference.get();
+            AlertDialog alertDialog = alertDialogWeakReference.get();
+
+            // Abort if the activity or the alert dialog is gone.
+            if ((activity == null) || (activity.isFinishing()) || (alertDialog == null)) {
+                return;
+            }
+
+            // Get a handle for the IP addresses text view.
+            TextView ipAddressesTextView = alertDialog.findViewById(R.id.ip_addresses);
+
+            // Remove the incorrect lint warning below that the view might be null.
+            assert ipAddressesTextView != null;
+
+            // Populate the IP addresses text view.
+            ipAddressesTextView.setText(ipAddresses);
+        }
+    }
 }