Implement Orbot proxy support. Fixes https://redmine.stoutner.com/issues/26.
[PrivacyBrowser.git] / app / src / main / java / com / stoutner / privacybrowser / SettingsFragment.java
index f52397b19abfb69df19d64d22f9b139fa9f3c135..60e250b2241f0337f86251cf64b8e4d27ba13fe2 100644 (file)
@@ -20,6 +20,7 @@
 package com.stoutner.privacybrowser;
 
 import android.annotation.SuppressLint;
+import android.app.Activity;
 import android.content.SharedPreferences;
 import android.os.Build;
 import android.os.Bundle;
@@ -39,180 +40,312 @@ public class SettingsFragment extends PreferenceFragment {
         // Initialize savedPreferences.
         savedPreferences = getPreferenceScreen().getSharedPreferences();
 
+        // Allow the user to access "dom_storage_enabled" if "javascript_enabled" is enabled.  The default is false.
+        final Preference domStorageEnabled = findPreference("dom_storage_enabled");
+        domStorageEnabled.setEnabled(savedPreferences.getBoolean("javascript_enabled", false));
+
+        // Allow the user to access "third_party_cookies_enabled" if "first_party_cookies_enabled" is enabled.  The default is false.
+        final Preference thirdPartyCookiesEnabled = findPreference("third_party_cookies_enabled");
+        thirdPartyCookiesEnabled.setEnabled(savedPreferences.getBoolean("first_party_cookies_enabled", false));
+
+        // Set the current user-agent as the summary text for the "user_agent" preference when the preference screen is loaded.
+        final Preference userAgentPreference = findPreference("user_agent");
+        switch (savedPreferences.getString("user_agent", "Default user agent")) {
+            case "Default user agent":
+                // Get the user agent text from the webview (which changes based on the version of Android and WebView installed).
+                // Once API >= 17 we can use getDefaultUserAgent() instead of getUserAgentString().
+                userAgentPreference.setSummary(MainWebViewActivity.mainWebView.getSettings().getUserAgentString());
+                break;
+
+            case "Custom user agent":
+                // We can't use the string from the array because it is referenced in code and can't be translated.
+                userAgentPreference.setSummary(R.string.custom_user_agent);
+                break;
+
+            default:
+                // Display the user agent from the preference as the summary text.
+                userAgentPreference.setSummary(savedPreferences.getString("user_agent", "Default user agent"));
+                break;
+        }
+
+        // Set the summary text for "custom_user_agent" (the default is "PrivacyBrowser/1.0") and enable it if "user_agent" it set to "Custom user agent".
+        final Preference customUserAgent = findPreference("custom_user_agent");
+        customUserAgent.setSummary(savedPreferences.getString("custom_user_agent", "PrivacyBrowser/1.0"));
+        customUserAgent.setEnabled(userAgentPreference.getSummary().equals("Custom user agent"));
+
 
         // Set the JavaScript-disabled search URL as the summary text for the JavaScript-disabled search preference when the preference screen is loaded.
         // The default is "https://duckduckgo.com/html/?q=".
         final Preference javaScriptDisabledSearchPreference = findPreference("javascript_disabled_search");
-        javaScriptDisabledSearchPreference.setSummary(savedPreferences.getString("javascript_disabled_search", "https://duckduckgo.com/html/?q="));
+        String javaScriptDisabledSearchString = savedPreferences.getString("javascript_disabled_search", "https://duckduckgo.com/html/?q=");
+        if (javaScriptDisabledSearchString.equals("Custom URL")) {
+            // If set to "Custom URL", use R.string.custom_url, which will be translated, instead of the array value, which will not.
+            javaScriptDisabledSearchPreference.setSummary(R.string.custom_url);
+        } else {
+            // Set the array value as the summary text.
+            javaScriptDisabledSearchPreference.setSummary(javaScriptDisabledSearchString);
+        }
 
         // Set the summary text for "javascript_disabled_search_custom_url" (the default is "") and enable it if "javascript_disabled_search" is set to "Custom URL".
         final Preference javaScriptDisabledSearchCustomURLPreference = findPreference("javascript_disabled_search_custom_url");
         javaScriptDisabledSearchCustomURLPreference.setSummary(savedPreferences.getString("javascript_disabled_search_custom_url", ""));
-        javaScriptDisabledSearchCustomURLPreference.setEnabled(javaScriptDisabledSearchPreference.getSummary().equals("Custom URL"));
+        javaScriptDisabledSearchCustomURLPreference.setEnabled(javaScriptDisabledSearchString.equals("Custom URL"));
 
-        // Set the JavaScript-enabed searchURL as the summary text for the JavaScript-enabled search preference when the preference screen is loaded.
+
+        // Set the JavaScript-enabled searchURL as the summary text for the JavaScript-enabled search preference when the preference screen is loaded.
         // The default is "https://duckduckgo.com/?q=".
         final Preference javaScriptEnabledSearchPreference = findPreference("javascript_enabled_search");
-        javaScriptEnabledSearchPreference.setSummary(savedPreferences.getString("javascript_enabled_search", "https://duckduckgo.com/?q="));
+        String javaScriptEnabledSearchString = savedPreferences.getString("javascript_enabled_search", "https://duckduckgo.com/?q=");
+        if (javaScriptEnabledSearchString.equals("Custom URL")) {
+            // If set to "Custom URL", use R.string.custom_url, which will be translated, instead of the array value, which will not.
+            javaScriptEnabledSearchPreference.setSummary(R.string.custom_url);
+        } else {
+            // Set the array value as the summary text.
+            javaScriptEnabledSearchPreference.setSummary(javaScriptEnabledSearchString);
+        }
 
         // Set the summary text for "javascript_enabled_search_custom_url" (the default is "") and enable it if "javascript_enabled_search" is set to "Custom URL".
         final Preference javaScriptEnabledSearchCustomURLPreference = findPreference("javascript_enabled_search_custom_url");
         javaScriptEnabledSearchCustomURLPreference.setSummary(savedPreferences.getString("javascript_enabled_search_custom_url", ""));
-        javaScriptEnabledSearchCustomURLPreference.setEnabled(javaScriptEnabledSearchPreference.getSummary().equals("Custom URL"));
+        javaScriptEnabledSearchCustomURLPreference.setEnabled(javaScriptEnabledSearchString.equals("Custom URL"));
+
 
-        // Set the homepage URL as the summary text for the Homepage preference when the preference screen is loaded.  The default is "https://www.duckduckgo.com".
+        // Set the homepage URL as the summary text for the `Homepage` preference when the preference screen is loaded.  The default is `https://www.duckduckgo.com`.
         final Preference homepagePreference = findPreference("homepage");
         homepagePreference.setSummary(savedPreferences.getString("homepage", "https://www.duckduckgo.com"));
 
+        // Set the default font size as the summary text for the `Default Font Size` preference when the preference screen is loaded.  The default is `100`.
+        final Preference defaultFontSizePreference = findPreference("default_font_size");
+        String defaultFontSizeString = savedPreferences.getString("default_font_size", "100");
+        defaultFontSizePreference.setSummary(defaultFontSizeString + "%%");
+
 
         // Listen for preference changes.
         preferencesListener = new SharedPreferences.OnSharedPreferenceChangeListener() {
             @Override
-            // Remove Android Studio's warning about the dangers of using SetJavaScriptEnabled.
+            // Remove Android Studio's warning about the dangers of using SetJavaScriptEnabled.  We know.
             @SuppressLint("SetJavaScriptEnabled")
             public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
 
-                // Several keys need to update the toggleJavaScript icon.
-                MenuItem toggleJavaScript = MainWebViewActivity.mainMenu.findItem(R.id.toggleJavaScript);
-
                 switch (key) {
                     case "javascript_enabled":
-                        // Set javaScriptEnabled to the new state.  The default is false.
+                        // Set `javaScriptEnabled` to the new state.  The default is `false`.
                         MainWebViewActivity.javaScriptEnabled = sharedPreferences.getBoolean("javascript_enabled", false);
 
-                        // Update mainWebView and reload the website.
+                        // Toggle the state of the `dom_storage_enabled` preference.  The default is `false`.
+                        final Preference domStorageEnabled = findPreference("dom_storage_enabled");
+                        domStorageEnabled.setEnabled(sharedPreferences.getBoolean("javascript_enabled", false));
+
+                        // Update `mainWebView`.
                         MainWebViewActivity.mainWebView.getSettings().setJavaScriptEnabled(MainWebViewActivity.javaScriptEnabled);
-                        MainWebViewActivity.mainWebView.reload();
-
-                        // Update the toggleJavaScript icon.
-                        if (MainWebViewActivity.javaScriptEnabled) {
-                            toggleJavaScript.setIcon(R.drawable.javascript_enabled);
-                        } else {
-                            if (MainWebViewActivity.firstPartyCookiesEnabled || MainWebViewActivity.domStorageEnabled) {
-                                toggleJavaScript.setIcon(R.drawable.warning);
-                            } else {
-                                toggleJavaScript.setIcon(R.drawable.privacy_mode);
-                            }
-                        }
-                        return;
+
+                        // Update the privacy icons.
+                        MainWebViewActivity.updatePrivacyIcons(MainWebViewActivity.privacyBrowserActivity);
+                        break;
 
                     case "first_party_cookies_enabled":
-                        // Set firstPartyCookiesEnabled to the new state.  The default is false.
+                        // Set `firstPartyCookiesEnabled` to the new state.  The default is `false`.
                         MainWebViewActivity.firstPartyCookiesEnabled = sharedPreferences.getBoolean("first_party_cookies_enabled", false);
 
+                        // Toggle the state of the `third_party_cookies_enabled` preference.  The default is `false`.
+                        final Preference thirdPartyCookiesEnabled = findPreference("third_party_cookies_enabled");
+                        thirdPartyCookiesEnabled.setEnabled(sharedPreferences.getBoolean("first_party_cookies_enabled", false));
+
+                        // Update `mainWebView`.
+                        MainWebViewActivity.cookieManager.setAcceptCookie(MainWebViewActivity.firstPartyCookiesEnabled);
+
                         // Update the checkbox in the options menu.
                         MenuItem firstPartyCookiesMenuItem = MainWebViewActivity.mainMenu.findItem(R.id.toggleFirstPartyCookies);
                         firstPartyCookiesMenuItem.setChecked(MainWebViewActivity.firstPartyCookiesEnabled);
 
-                        // Update mainWebView and reload the website.
-                        MainWebViewActivity.cookieManager.setAcceptCookie(MainWebViewActivity.firstPartyCookiesEnabled);
-                        MainWebViewActivity.mainWebView.reload();
-
-                        // Update the toggleJavaScript icon.
-                        if (MainWebViewActivity.javaScriptEnabled) {
-                            toggleJavaScript.setIcon(R.drawable.javascript_enabled);
-                        } else {
-                            if (MainWebViewActivity.firstPartyCookiesEnabled || MainWebViewActivity.domStorageEnabled) {
-                                toggleJavaScript.setIcon(R.drawable.warning);
-                            } else {
-                                toggleJavaScript.setIcon(R.drawable.privacy_mode);
-                            }
-                        }
-                        return;
+                        // Update the privacy icons.
+                        MainWebViewActivity.updatePrivacyIcons(MainWebViewActivity.privacyBrowserActivity);
+                        break;
 
                     case "third_party_cookies_enabled":
-                        // Set thirdPartyCookiesEnabled to the new state.  The default is false.
+                        // Set `thirdPartyCookiesEnabled` to the new state.  The default is `false`.
                         MainWebViewActivity.thirdPartyCookiesEnabled = sharedPreferences.getBoolean("third_party_cookies_enabled", false);
 
                         // Update the checkbox in the options menu.
                         MenuItem thirdPartyCookiesMenuItem = MainWebViewActivity.mainMenu.findItem(R.id.toggleThirdPartyCookies);
                         thirdPartyCookiesMenuItem.setChecked(MainWebViewActivity.thirdPartyCookiesEnabled);
 
-                        // Update mainWebView and reload the website if API >= 21.
+                        // Update `mainWebView` if API >= 21.
                         if (Build.VERSION.SDK_INT >= 21) {
                             MainWebViewActivity.cookieManager.setAcceptThirdPartyCookies(MainWebViewActivity.mainWebView, MainWebViewActivity.thirdPartyCookiesEnabled);
-                            MainWebViewActivity.mainWebView.reload();
                         }
-                        return;
+                        break;
 
                     case "dom_storage_enabled":
-                        // Set domStorageEnabled to the new state.  The default is false.
+                        // Set `domStorageEnabled` to the new state.  The default is `false`.
                         MainWebViewActivity.domStorageEnabled = sharedPreferences.getBoolean("dom_storage_enabled", false);
 
                         // Update the checkbox in the options menu.
                         MenuItem domStorageMenuItem = MainWebViewActivity.mainMenu.findItem(R.id.toggleDomStorage);
                         domStorageMenuItem.setChecked(MainWebViewActivity.domStorageEnabled);
 
-                        // Update mainWebView and reload the website.
+                        // Update `mainWebView`.
                         MainWebViewActivity.mainWebView.getSettings().setDomStorageEnabled(MainWebViewActivity.domStorageEnabled);
-                        MainWebViewActivity.mainWebView.reload();
-
-                        // Update the toggleJavaScript icon.
-                        if (MainWebViewActivity.javaScriptEnabled) {
-                            toggleJavaScript.setIcon(R.drawable.javascript_enabled);
-                        } else {
-                            if (MainWebViewActivity.firstPartyCookiesEnabled || MainWebViewActivity.domStorageEnabled) {
-                                toggleJavaScript.setIcon(R.drawable.warning);
-                            } else {
-                                toggleJavaScript.setIcon(R.drawable.privacy_mode);
-                            }
+
+                        // Update the privacy icons.
+                        MainWebViewActivity.updatePrivacyIcons(MainWebViewActivity.privacyBrowserActivity);
+                        break;
+
+                    case "save_form_data_enabled":
+                        // Set `saveFormDataEnabled` to the new state.  The default is `false`.
+                        MainWebViewActivity.saveFormDataEnabled = sharedPreferences.getBoolean("save_form_data_enabled", false);
+
+                        // Update the checkbox in the options menu.
+                        MenuItem saveFormDataMenuItem = MainWebViewActivity.mainMenu.findItem(R.id.toggleSaveFormData);
+                        saveFormDataMenuItem.setChecked(MainWebViewActivity.saveFormDataEnabled);
+
+                        // Update `mainWebView`.
+                        MainWebViewActivity.mainWebView.getSettings().setSaveFormData(MainWebViewActivity.saveFormDataEnabled);
+
+                        // Update the privacy icons.
+                        MainWebViewActivity.updatePrivacyIcons(MainWebViewActivity.privacyBrowserActivity);
+                        break;
+
+                    case "user_agent":
+                        String userAgentString = sharedPreferences.getString("user_agent", "Default user agent");
+
+                        switch (userAgentString) {
+                            case "Default user agent":
+                                // Set the default user agent on `mainWebView`, display the user agent as the summary text for `userAgentPreference`, and disable `customUserAgent`.
+                                // Once API >= 17 we can use getDefaultUserAgent().  For now, setUserAgentString("") sets the WebView's default user agent.
+                                MainWebViewActivity.mainWebView.getSettings().setUserAgentString("");
+                                userAgentPreference.setSummary(MainWebViewActivity.mainWebView.getSettings().getUserAgentString());
+                                customUserAgent.setEnabled(false);
+                                break;
+
+                            case "Custom user agent":
+                                // Set the custom user agent on mainWebView, display "Custom user agent" as the summary text for userAgentPreference, and enable customUserAgent.
+                                MainWebViewActivity.mainWebView.getSettings().setUserAgentString(sharedPreferences.getString("custom_user_agent", "PrivacyBrowser/1.0"));
+                                userAgentPreference.setSummary(R.string.custom_user_agent);
+                                customUserAgent.setEnabled(true);
+                                break;
+
+                            default:
+                                // Set the user agent on mainWebView, display the user agent as the summary text for userAgentPreference, and disable customUserAgent.
+                                MainWebViewActivity.mainWebView.getSettings().setUserAgentString(sharedPreferences.getString("user_agent", "Default user agent"));
+                                userAgentPreference.setSummary(MainWebViewActivity.mainWebView.getSettings().getUserAgentString());
+                                customUserAgent.setEnabled(false);
+                                break;
                         }
-                        return;
+                        break;
 
-                    case "javascript_disabled_search":
-                        // Set the new search URL as the summary text for the JavaScript-disabled search preference.  The default is "https://duckduckgo.com/html/?q=".
-                        javaScriptDisabledSearchPreference.setSummary(sharedPreferences.getString("javascript_disabled_search", "https://duckduckgo.com/html/?q="));
+                    case "custom_user_agent":
+                        // Set the new custom user agent as the summary text for "custom_user_agent".  The default is "PrivacyBrowser/1.0".
+                        customUserAgent.setSummary(sharedPreferences.getString("custom_user_agent", "PrivacyBrowser/1.0"));
+
+                        // Update mainWebView's user agent.  The default is "PrivacyBrowser/1.0".
+                        MainWebViewActivity.mainWebView.getSettings().setUserAgentString(sharedPreferences.getString("custom_user_agent", "PrivacyBrowser/1.0"));
+                        break;
 
-                        // Enable "javascript_disabled_search_custom_url" if "javascript_disabled_search" is set to "Custom URL".
-                        javaScriptDisabledSearchCustomURLPreference.setEnabled(javaScriptDisabledSearchPreference.getSummary().equals("Custom URL"));
+                    case "proxy_through_orbot":
+                        // Get a handle for `settingsActivity`.
+                        Activity settingsActivity = getActivity();
 
-                        // Update the javaScriptDisabledSearchURL variable.  The default is "https://duckduckgo.com/html/?q=".
-                        MainWebViewActivity.javaScriptDisabledSearchURL = sharedPreferences.getString("javascript_disabled_search", "https://duckduckgo.com/html/?q=");
-                        return;
+                        // Update the proxy.  The default is `false`
+                        if (sharedPreferences.getBoolean("proxy_through_orbot", false)) {  // Orbot proxies on localhost port 8118.
+                            OrbotProxyHelper.setProxy(MainWebViewActivity.privacyBrowserContext, settingsActivity, "localhost", "8118");
+                        } else {  // Disable the proxy by setting the host to `null` and the port to `0`.
+                            OrbotProxyHelper.setProxy(MainWebViewActivity.privacyBrowserContext, settingsActivity, "", "0");
+                        }
+
+                    case "javascript_disabled_search":
+                        String newJavaScriptDisabledSearchString = sharedPreferences.getString("javascript_disabled_search", "https://duckduckgo.com/html/?q=");
+                        if (newJavaScriptDisabledSearchString.equals("Custom URL")) {
+                            // Set the summary text to R.string.custom_url, which will be translated.
+                            javaScriptDisabledSearchPreference.setSummary(R.string.custom_url);
+
+                            // Update the javaScriptDisabledSearchURL variable.  The default is "".
+                            MainWebViewActivity.javaScriptDisabledSearchURL = sharedPreferences.getString("javascript_disabled_search_custom_url", "");
+                        } else {  // javascript_disabled_search is not set to Custom.
+                            // Set the new search URL as the summary text for the JavaScript-disabled search preference.  The default is "https://duckduckgo.com/html/?q=".
+                            javaScriptDisabledSearchPreference.setSummary(newJavaScriptDisabledSearchString);
+
+                            // Update the javaScriptDisabledSearchURL variable.  The default is "https://duckduckgo.com/html/?q=".
+                            MainWebViewActivity.javaScriptDisabledSearchURL = newJavaScriptDisabledSearchString;
+                        }
+
+                        // Enable or disable javaScriptDisabledSearchCustomURLPreference.
+                        javaScriptDisabledSearchCustomURLPreference.setEnabled(newJavaScriptDisabledSearchString.equals("Custom URL"));
+                        break;
 
                     case "javascript_disabled_search_custom_url":
                         // Set the new custom search URL as the summary text for "javascript_disabled_search_custom_url".  The default is "".
                         javaScriptDisabledSearchCustomURLPreference.setSummary(sharedPreferences.getString("javascript_disabled_search_custom_url", ""));
 
                         // Update javaScriptDisabledSearchCustomURL.  The default is "".
-                        MainWebViewActivity.javaScriptDisabledSearchCustomURL = sharedPreferences.getString("javascript_disabled_search_custom_url", "");
+                        MainWebViewActivity.javaScriptDisabledSearchURL = sharedPreferences.getString("javascript_disabled_search_custom_url", "");
+                        break;
 
                     case "javascript_enabled_search":
-                        // Set the new search URL as the summary text for the JavaScript-enabled search preference.  The default is "https://duckduckgo.com/?q=".
-                        javaScriptEnabledSearchPreference.setSummary(sharedPreferences.getString("javascript_enabled_search", "https://duckduckgo.com/?q="));
-
-                        // Enable "javascript_enabled_search_custom_url" if "javascript_enabled_search" is set to "Custom URL".
-                        javaScriptEnabledSearchCustomURLPreference.setEnabled(javaScriptEnabledSearchPreference.getSummary().equals("Custom URL"));
+                        String newJavaScriptEnabledSearchString = sharedPreferences.getString("javascript_enabled_search", "https://duckduckgo.com/?q=");
+                        if (newJavaScriptEnabledSearchString.equals("Custom URL")) {
+                            // Set the summary text to R.string.custom_url, which will be translated.
+                            javaScriptEnabledSearchPreference.setSummary(R.string.custom_url);
+
+                            // Update the javaScriptEnabledSearchURL variable.  The default is "".
+                            MainWebViewActivity.javaScriptEnabledSearchURL = sharedPreferences.getString("javascript_enabled_search_custom_url", "");
+                        } else { // javascript_enabled_search is not set to Custom.
+                            // Set the new search URL as the summary text for the JavaScript-enabled search preference.  The default is "https://duckduckgo.com/?q=".
+                            javaScriptEnabledSearchPreference.setSummary(newJavaScriptEnabledSearchString);
+
+                            // Update the javaScriptEnabledSearchURL variable.  The default is "https://duckduckgo.com/?q=".
+                            MainWebViewActivity.javaScriptEnabledSearchURL = newJavaScriptEnabledSearchString;
+                        }
 
-                        // Update the javaScriptEnabledSearchURL variable.  The default is "https://duckduckgo.com/?q=".
-                        MainWebViewActivity.javaScriptEnabledSearchURL = sharedPreferences.getString("javascript_enabled_search", "https://duckduckgo.com/?q=");
-                        return;
+                        // Enable or disable javaScriptEnabledSearchCustomURLPreference.
+                        javaScriptEnabledSearchCustomURLPreference.setEnabled(newJavaScriptEnabledSearchString.equals("Custom URL"));
+                        break;
 
                     case "javascript_enabled_search_custom_url":
-                        // Set the new custom search URL as the summary text for "javascript_enabled_search_custom_url".  The default is "".
+                        // Set the new custom search URL as the summary text for `javascript_enabled_search_custom_url`.  The default is ``.
                         javaScriptEnabledSearchCustomURLPreference.setSummary(sharedPreferences.getString("javascript_enabled_search_custom_url", ""));
 
-                        // Update javaScriptEnabledSearchCustomURL.  The default is "".
-                        MainWebViewActivity.javaScriptEnabledSearchCustomURL = sharedPreferences.getString("javascript_enabled_search_custom_url", "");
+                        // Update javaScriptEnabledSearchCustomURL.  The default is ``.
+                        MainWebViewActivity.javaScriptEnabledSearchURL = sharedPreferences.getString("javascript_enabled_search_custom_url", "");
+                        break;
+
+                    case "do_not_track":
+                        // Update `customHeaders`.  The default is `true`.
+                        if (sharedPreferences.getBoolean("do_not_track", true)) {
+                            MainWebViewActivity.customHeaders.put("DNT", "1");
+                        } else {  // Remove the Do Not Track header.
+                            MainWebViewActivity.customHeaders.remove("DNT");
+                        }
 
                     case "homepage":
-                        // Set the new homepage URL as the summary text for the Homepage preference.  The default is "https://www.duckduckgo.com".
+                        // Set the new homepage URL as the summary text for the Homepage preference.  The default is `https://www.duckduckgo.com`.
                         homepagePreference.setSummary(sharedPreferences.getString("homepage", "https://www.duckduckgo.com"));
 
-                        // Update the homepage variable.  The default is "https://www.duckduckgo.com".
+                        // Update the homepage variable.  The default is `https://www.duckduckgo.com`.
                         MainWebViewActivity.homepage = sharedPreferences.getString("homepage", "https://www.duckduckgo.com");
-                        return;
+                        break;
+
+                    case "default_font_size":
+                        // Get the default font size as a string.  The default is `100`.
+                        String newDefaultFontSizeString = sharedPreferences.getString("default_font_size", "100");
+
+                        // Update the font size on `mainWebView`.  The default is `100`.
+                        MainWebViewActivity.mainWebView.getSettings().setTextZoom(Integer.valueOf(newDefaultFontSizeString));
+
+                        // Update the summary text of `default_font_size`.
+                        defaultFontSizePreference.setSummary(newDefaultFontSizeString + "%%");
 
                     case "swipe_to_refresh_enabled":
-                        // Set swipeToRefreshEnabled to the new state.  The default is true.
+                        // Set `swipeToRefreshEnabled` to the new state.  The default is `true`.
                         MainWebViewActivity.swipeToRefreshEnabled = sharedPreferences.getBoolean("swipe_to_refresh_enabled", true);
 
-                        // Update swipeRefreshLayout to match the new state.
+                        // Update `swipeRefreshLayout` to match the new state.
                         MainWebViewActivity.swipeToRefresh.setEnabled(MainWebViewActivity.swipeToRefreshEnabled);
-                        return;
+                        break;
 
-                    // If no match, do nothing.
                     default:
+                        // If no match, do nothing.
+                        break;
                 }
             }
         };
@@ -223,15 +356,15 @@ public class SettingsFragment extends PreferenceFragment {
 
     // It is necessary to re-register the listener on every resume or it will randomly stop working because apps can be paused and resumed at any time
     // even while running in the foreground.
-    @Override
-    public void onResume() {
-        super.onResume();
-        savedPreferences.registerOnSharedPreferenceChangeListener(preferencesListener);
-    }
-
     @Override
     public void onPause() {
         super.onPause();
         savedPreferences.unregisterOnSharedPreferenceChangeListener(preferencesListener);
     }
+
+    @Override
+    public void onResume() {
+        super.onResume();
+        savedPreferences.registerOnSharedPreferenceChangeListener(preferencesListener);
+    }
 }