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

/*
 * Copyright © 2015-2018 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.DialogFragment;
import android.app.DownloadManager;
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.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.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.support.annotation.NonNull;
import android.support.design.widget.CoordinatorLayout;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.NavigationView;
import android.support.design.widget.Snackbar;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
// `ShortcutInfoCompat`, `ShortcutManagerCompat`, and `IconCompat` can be switched to the non-compat version once API >= 26.
import android.support.v4.content.pm.ShortcutInfoCompat;
import android.support.v4.content.pm.ShortcutManagerCompat;
import android.support.v4.graphics.drawable.IconCompat;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.app.AppCompatDialogFragment;
import android.support.v7.widget.Toolbar;
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.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 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.PinnedSslCertificateMismatchDialog;
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.net.MalformedURLException;
import java.net.URL;
import java.net.URLDecoder;
import java.net.URLEncoder;
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, PinnedSslCertificateMismatchDialog.PinnedSslCertificateMismatchListener,
        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;

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

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

    // `orbotStatus` is public static so it can be accessed from `OrbotProxyHelper`.  It is also used in `onCreate()` and `onResume()`.
    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;
    int blockedRequests;
    int easyListBlockedRequests;
    int easyPrivacyBlockedRequests;
    int fanboysAnnoyanceListBlockedRequests;
    int fanboysSocialBlockingListBlockedRequests;
    int ultraPrivacyBlockedRequests;
    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 `PinnedSslCertificateMismatchDialog`.  It is also used in `onCreate()`, `onOptionsItemSelected()`, and `applyDomainSettings()`.
    public static int domainSettingsDatabaseId;

    // The pinned domain SSL Certificate variables are public static so they can be accessed from `PinnedSslCertificateMismatchDialog`.  They are also used in `onCreate()` and `applyDomainSettings()`.
    public static String pinnedDomainSslIssuedToCNameString;
    public static String pinnedDomainSslIssuedToONameString;
    public static String pinnedDomainSslIssuedToUNameString;
    public static String pinnedDomainSslIssuedByCNameString;
    public static String pinnedDomainSslIssuedByONameString;
    public static String pinnedDomainSslIssuedByUNameString;
    public static Date pinnedDomainSslStartDate;
    public static Date pinnedDomainSslEndDate;

    // 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;


    // `appBar` is used in `onCreate()`, `onOptionsItemSelected()`, `closeFindOnPage()`, and `applyAppSettings()`.
    private ActionBar appBar;

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

    // `favoriteIconDefaultBitmap` is used in `onCreate()` and `applyDomainSettings`.
    private Bitmap favoriteIconDefaultBitmap;

    // `drawerLayout` is used in `onCreate()`, `onNewIntent()`, `onBackPressed()`, and `onRestart()`.
    private DrawerLayout drawerLayout;

    // `rootCoordinatorLayout` is used in `onCreate()` and `applyAppSettings()`.
    private CoordinatorLayout rootCoordinatorLayout;

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

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

    // `swipeRefreshLayout` is used in `onCreate()`, `onPrepareOptionsMenu()`, `onOptionsItemSelected()`, and `onRestart()`.
    private SwipeRefreshLayout swipeRefreshLayout;

    // `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()` and  `applyDomainSettings()`.
    private boolean nightMode;

    // `displayWebpageImagesBoolean` is used in `applyAppSettings()` and `applyDomainSettings()`.
    private boolean displayWebpageImagesBoolean;

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

    // `searchURL` is used in `loadURLFromTextBox()` and `applyAppSettings()`.
    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 blockAllThirdParyRequestsMenuItem;

    // 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()` and `applyAppSettings()`.
    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;

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

    // `ignorePinnedSslCertificateForDomain` is used in `onCreate()`, `onSslMismatchProceed()`, and `applyDomainSettings()`.
    private boolean ignorePinnedSslCertificate;

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

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

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

    // `displayWebpageImagesInt` is used in `applyDomainSettings()` and `setDisplayWebpageImages()`.
    private int displayWebpageImagesInt;

    // `onTheFlyDisplayImagesSet` is used in `applyDomainSettings()` and `setDisplayWebpageImages()`.
    private boolean onTheFlyDisplayImagesSet;

    // `waitingForOrbotData` is used in `onCreate()` and `applyAppSettings()`.
    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;

    // `drawerToggle` is used in `onCreate()`, `onPostCreate()`, `onConfigurationChanged()`, `onNewIntent()`, and `onNavigationItemSelected()`.
    private ActionBarDrawerToggle drawerToggle;

    // `supportAppBar` is used in `onCreate()`, `onOptionsItemSelected()`, and `closeFindOnPage()`.
    private Toolbar supportAppBar;

    // `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;

    // `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;

    // `mainWebViewRelativeLayout` is used in `onCreate()` and `onNavigationItemSelected()`.
    private RelativeLayout mainWebViewRelativeLayout;

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

    // `pinnedDomainSslCertificate` is used in `onCreate()` and `applyDomainSettings()`.
    private boolean pinnedDomainSslCertificate;

    // `bookmarksDatabaseHelper` is used in `onCreate()`, `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 `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.  We have to use the deprecated `getColor()` 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 a handle for `inputMethodManager`.
        inputMethodManager = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);

        // `SupportActionBar` from `android.support.v7.app.ActionBar` must be used until the minimum API is >= 21.
        supportAppBar = findViewById(R.id.app_bar);
        setSupportActionBar(supportAppBar);
        appBar = getSupportActionBar();

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

        // Add the custom `url_app_bar` layout, which shows the favorite icon and the URL text bar.
        appBar.setCustomView(R.layout.url_app_bar);
        appBar.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(getResources().getColor(R.color.red_a700));
        initialGrayColorSpan = new ForegroundColorSpan(getResources().getColor(R.color.gray_500));
        finalGrayColorSpan = new ForegroundColorSpan(getResources().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 `urlTextBox`.
                // Remove the highlighting.
                urlTextBox.getText().removeSpan(redColorSpan);
                urlTextBox.getText().removeSpan(initialGrayColorSpan);
                urlTextBox.getText().removeSpan(finalGrayColorSpan);
            } else {  // The user has stopped editing `urlTextBox`.
                // 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.
                try {
                    loadUrlFromTextBox();
                } catch (UnsupportedEncodingException e) {
                    e.printStackTrace();
                }
                // 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 we are 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 accessed.
        drawerLayout = findViewById(R.id.drawerlayout);
        rootCoordinatorLayout = findViewById(R.id.root_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);
        mainWebViewRelativeLayout = findViewById(R.id.main_webview_relativelayout);
        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(getResources().getDrawable(R.drawable.bookmarks_dark));
            createBookmarkFolderFab.setImageDrawable(getResources().getDrawable(R.drawable.create_folder_dark));
            createBookmarkFab.setImageDrawable(getResources().getDrawable(R.drawable.create_bookmark_dark));
            bookmarksListView.setBackgroundColor(getResources().getColor(R.color.gray_850));
        } else {
            launchBookmarksActivityFab.setImageDrawable(getResources().getDrawable(R.drawable.bookmarks_light));
            createBookmarkFolderFab.setImageDrawable(getResources().getDrawable(R.drawable.create_folder_light));
            createBookmarkFab.setImageDrawable(getResources().getDrawable(R.drawable.create_bookmark_light));
            bookmarksListView.setBackgroundColor(getResources().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 `CreateBookmarkFolderDialog` `AlertDialog` and name the instance `@string/create_folder`.
            AppCompatDialogFragment createBookmarkFolderDialog = new CreateBookmarkFolderDialog();
            createBookmarkFolderDialog.show(getSupportFragmentManager(), getResources().getString(R.string.create_folder));
        });

        // Set the create new bookmark FAB to display an alert dialog.
        createBookmarkFab.setOnClickListener(view -> {
            // Show the `CreateBookmarkDialog` `AlertDialog` and name the instance `@string/create_bookmark`.
            AppCompatDialogFragment createBookmarkDialog = new CreateBookmarkDialog();
            createBookmarkDialog.show(getSupportFragmentManager(), getResources().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 `appBar`.
                        appBar.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.
                             */
                            rootCoordinatorLayout.setSystemUiVisibility(View.SYSTEM_UI_FLAG_FULLSCREEN | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);

                            // Set `rootCoordinatorLayout` to fill the whole screen.
                            rootCoordinatorLayout.setFitsSystemWindows(false);
                        } else {  // Hide everything except the status and navigation bars.
                            // Set `rootCoordinatorLayout` to fit under the status and navigation bars.
                            rootCoordinatorLayout.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 `appBar`.
                        appBar.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_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 `rootCoordinatorLayout`.
                        rootCoordinatorLayout.setSystemUiVisibility(0);

                        // Constrain `rootCoordinatorLayout` inside the status and navigation bars.
                        rootCoordinatorLayout.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 v, MotionEvent event) -> {
            // Call `performClick()` on the view, which is required for accessibility.
            v.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 = (TextView) 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 = findViewById(R.id.swipe_refreshlayout);
        swipeRefreshLayout.setColorSchemeResources(R.color.blue_700);
        swipeRefreshLayout.setOnRefreshListener(() -> mainWebView.reload());

        // `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.  `this` specifies the context.  The two `nulls` do not specify the database name or a `CursorFactory`.
        // 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.getBookmarkCursor(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`.
                AppCompatDialogFragment editFolderDialog = EditBookmarkFolderDialog.folderDatabaseId(databaseId);
                editFolderDialog.show(getSupportFragmentManager(), getResources().getString(R.string.edit_folder));
            } else {
                // Show the edit bookmark `AlertDialog` and name the instance `@string/edit_bookmark`.
                AppCompatDialogFragment editBookmarkDialog = EditBookmarkDialog.bookmarkDatabaseId(databaseId);
                editBookmarkDialog.show(getSupportFragmentManager(), getResources().getString(R.string.edit_bookmark));
            }

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

        // 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.
                    // 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.
                    urlTextBox.clearFocus();
                }
            }
        });

        // drawerToggle creates the hamburger icon at the start of the AppBar.
        drawerToggle = new ActionBarDrawerToggle(this, drawerLayout, supportAppBar, 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.  `!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;}'; 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 one.  This prevents the display of the `WebView` while it is still loading.
                                    if (progressBar.getVisibility() == View.GONE) {
                                        mainWebView.setVisibility(View.VISIBLE);
                                    }
                                };

                                // Use `displayWebViewHandler` to delay the displaying of `mainWebView` for 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.
                 */
                rootCoordinatorLayout.setSystemUiVisibility(View.SYSTEM_UI_FLAG_FULLSCREEN | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);

                // Set `rootCoordinatorLayout` to fill the entire screen.
                rootCoordinatorLayout.setFitsSystemWindows(false);

                // 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.
                         */
                        rootCoordinatorLayout.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 `rootCoordinatorLayout`.
                        rootCoordinatorLayout.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 `appBar` if `findOnPageLinearLayout` is not visible.
                    if (findOnPageLinearLayout.getVisibility() == View.GONE) {
                        appBar.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(), getFragmentManager(), getString(R.string.ad_id));
                    }

                    // Remove any `SYSTEM_UI` flags from `rootCoordinatorLayout`.
                    rootCoordinatorLayout.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 `rootCoordinatorLayout` inside the status and navigation bars.
                    rootCoordinatorLayout.setFitsSystemWindows(true);
                }

                // 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_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 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 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.
                    // Get a handle for 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(getFragmentManager(), 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 WRITE_EXTERNAL_STORAGE permission has already been granted.
                // Get a handle for the download file alert dialog.
                AppCompatDialogFragment downloadFileDialogFragment = DownloadFileDialog.fromUrl(url, contentDisposition, contentLength);

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

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

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

        // Set `mainWebView` 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 `mainWebView` 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 the intent that started the app.
        final Intent launchingIntent = getIntent();

        // Extract the launching intent data as `launchingIntentUriData`.
        final Uri launchingIntentUriData = launchingIntent.getData();

        // Convert the launching intent URI data (if it exists) to a string and store it in `formattedUrlString`.
        if (launchingIntentUriData != null) {
            formattedUrlString = launchingIntentUriData.toString();
        }

        // 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.domain_settings_spinner_item);
        userAgentDataArray = getResources().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.
                    applyDomainSettings(url, true, false);

                    // 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);
                        blockAllThirdParyRequestsMenuItem.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 defult 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.
                AppCompatDialogFragment httpAuthenticationDialogFragment = HttpAuthenticationDialog.displayDialog(host, realm);
                httpAuthenticationDialogFragment.show(getSupportFragmentManager(), 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) {
                // 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) {  // We are not waiting on Orbot, so we need to process the URL.
                    // We need to update `formattedUrlString` 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();

                    // Apply any custom domain settings if the URL was loaded by navigating history.
                    if (navigatingHistory) {
                        // Reset `navigatingHistory`.
                        navigatingHistory = false;

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

                    // 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.
                    urlIsLoading = true;

                    // 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) {
                // 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);
                        }
                    }
                }

                // Reset `urlIsLoading`, which is used to prevent reloads on redirect if the user agent changes.
                urlIsLoading = false;

                // 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 `urlTextBox` 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 `formattedUrlString`.
                        formattedUrlString = url;

                        // Only update `urlTextBox` 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 `PinnedSslCertificateMismatchDialog`.
                    sslCertificate = mainWebView.getCertificate();

                    // Check the current website SSL certificate against the pinned SSL certificate if there is a pinned SSL certificate the user has not chosen to ignore it for this session.
                    if (pinnedDomainSslCertificate && !ignorePinnedSslCertificate) {
                        // 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 pinnedDomainSslStartDateString = "";
                        String pinnedDomainSslEndDateString = "";

                        // Convert the `Dates` to `Strings` if they are not `null`.
                        if (currentWebsiteSslStartDate != null) {
                            currentWebsiteSslStartDateString = currentWebsiteSslStartDate.toString();
                        }

                        if (currentWebsiteSslEndDate != null) {
                            currentWebsiteSslEndDateString = currentWebsiteSslEndDate.toString();
                        }

                        if (pinnedDomainSslStartDate != null) {
                            pinnedDomainSslStartDateString = pinnedDomainSslStartDate.toString();
                        }

                        if (pinnedDomainSslEndDate != null) {
                            pinnedDomainSslEndDateString = pinnedDomainSslEndDate.toString();
                        }

                        // Check to see if the pinned SSL certificate matches the current website certificate.
                        if (!currentWebsiteIssuedToCName.equals(pinnedDomainSslIssuedToCNameString) || !currentWebsiteIssuedToOName.equals(pinnedDomainSslIssuedToONameString) ||
                                !currentWebsiteIssuedToUName.equals(pinnedDomainSslIssuedToUNameString) || !currentWebsiteIssuedByCName.equals(pinnedDomainSslIssuedByCNameString) ||
                                !currentWebsiteIssuedByOName.equals(pinnedDomainSslIssuedByONameString) || !currentWebsiteIssuedByUName.equals(pinnedDomainSslIssuedByUNameString) ||
                                !currentWebsiteSslStartDateString.equals(pinnedDomainSslStartDateString) || !currentWebsiteSslEndDateString.equals(pinnedDomainSslEndDateString)) {
                            // The pinned SSL certificate doesn't match the current domain certificate.
                            //Display the pinned SSL certificate mismatch `AlertDialog`.
                            AppCompatDialogFragment pinnedSslCertificateMismatchDialogFragment = new PinnedSslCertificateMismatchDialog();
                            pinnedSslCertificateMismatchDialogFragment.show(getSupportFragmentManager(), getString(R.string.ssl_certificate_mismatch));
                        }
                    }
                }
            }

            // 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 (pinnedDomainSslCertificate &&
                        currentWebsiteIssuedToCName.equals(pinnedDomainSslIssuedToCNameString) && currentWebsiteIssuedToOName.equals(pinnedDomainSslIssuedToONameString) &&
                        currentWebsiteIssuedToUName.equals(pinnedDomainSslIssuedToUNameString) && currentWebsiteIssuedByCName.equals(pinnedDomainSslIssuedByCNameString) &&
                        currentWebsiteIssuedByOName.equals(pinnedDomainSslIssuedByONameString) && currentWebsiteIssuedByUName.equals(pinnedDomainSslIssuedByUNameString) &&
                        currentWebsiteSslStartDate.equals(pinnedDomainSslStartDate) && currentWebsiteSslEndDate.equals(pinnedDomainSslEndDate)) {
                    // 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`.
                    AppCompatDialogFragment sslCertificateErrorDialogFragment = SslCertificateErrorDialog.displayDialog(error);
                    sslCertificateErrorDialogFragment.show(getSupportFragmentManager(), getString(R.string.ssl_certificate_error));
                }
            }
        });

        // 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);

        // Check to see if the intent contains a new URL.
        if (intent.getData() != null) {
            // Get the intent data.
            final Uri intentUriData = intent.getData();

            // Load the website.
            loadUrl(intentUriData.toString());

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

        if (displayingFullScreenVideo) {
            // 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.
             */
            rootCoordinatorLayout.setSystemUiVisibility(View.SYSTEM_UI_FLAG_FULLSCREEN | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);
        }
    }

    @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);

        // 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);
        blockAllThirdParyRequestsMenuItem = 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 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);

        // 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);
        blockAllThirdParyRequestsMenuItem.setChecked(blockAllThirdPartyRequests);
        swipeToRefreshMenuItem.setChecked(swipeRefreshLayout.isEnabled());
        displayImagesMenuItem.setChecked(mainWebView.getSettings().getLoadsImagesAutomatically());

        // 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));
        blockAllThirdParyRequestsMenuItem.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();

        // Set the commands that relate to the menu entries.
        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() {
                            @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 {
                                            // `null` indicates no callback.
                                            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() {
                            @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();

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

                                            // Multiple commands must be used because `Runtime.exec()` does not like `*`.
                                            privacyBrowserRuntime.exec("rm -rf " + privateDataDirectoryString + "/app_webview/IndexedDB");
                                            privacyBrowserRuntime.exec("rm -f " + privateDataDirectoryString + "/app_webview/QuotaManager");
                                            privacyBrowserRuntime.exec("rm -f " + privateDataDirectoryString + "/app_webview/QuotaManager-journal");
                                            privacyBrowserRuntime.exec("rm -rf " + privateDataDirectoryString + "/app_webview/databases");
                                        } catch (IOException e) {
                                            // Do nothing if an error is thrown.
                                        }
                                }
                            }
                        })
                        .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() {
                            @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();