Create an `Open with App` menu item. https://redmine.stoutner.com/issues/336

[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.app.SearchManager;
import android.content.ActivityNotFoundException;
import android.content.BroadcastReceiver;
import android.content.ClipData;
import android.content.ClipboardManager;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.SharedPreferences;
import android.content.pm.PackageManager;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Typeface;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.net.Uri;
import android.net.http.SslCertificate;
import android.net.http.SslError;
import android.os.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()`, `loadUrlFromTextBox()`, and `applyProxyThroughOrbot()`.
    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()`, `onResume()`, and `applyProxyThroughOrbot()`.
    public static String orbotStatus;

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

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

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

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

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

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

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

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

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

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

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

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

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

    // `domainSettingsDatabaseId` is public static so it can be accessed from `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()`, `applyAppSettings()`, and `applyProxyThroughOrbot()`.
    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 `applyProxyThroughOrbot()`.
    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()`, `onPrepareOptionsMenu()`, `onOptionsItemSelected()`, and  `applyDomainSettings()`.
    private boolean nightMode;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

    // `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;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

        // Get a handle for the resources.
        Resources resources = getResources();

        // 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(resources.getColor(R.color.red_a700));
        initialGrayColorSpan = new ForegroundColorSpan(resources.getColor(R.color.gray_500));
        finalGrayColorSpan = new ForegroundColorSpan(resources.getColor(R.color.gray_500));

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

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

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

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

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

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

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

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

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

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

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

        // Get handles for views that need to be 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(resources.getDrawable(R.drawable.bookmarks_dark));
            createBookmarkFolderFab.setImageDrawable(resources.getDrawable(R.drawable.create_folder_dark));
            createBookmarkFab.setImageDrawable(resources.getDrawable(R.drawable.create_bookmark_dark));
            bookmarksListView.setBackgroundColor(resources.getColor(R.color.gray_850));
        } else {
            launchBookmarksActivityFab.setImageDrawable(resources.getDrawable(R.drawable.bookmarks_light));
            createBookmarkFolderFab.setImageDrawable(resources.getDrawable(R.drawable.create_folder_light));
            createBookmarkFab.setImageDrawable(resources.getDrawable(R.drawable.create_bookmark_light));
            bookmarksListView.setBackgroundColor(resources.getColor(R.color.white));
        }

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

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

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

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

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

                    if (inFullScreenBrowsingMode) {  // Switch to full screen mode.
                        // Hide the `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_unit_id));
                        }

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

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

                        // Remove any `SYSTEM_UI` flags from `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.swiperefreshlayout);
        swipeRefreshLayout.setOnRefreshListener(() -> mainWebView.reload());

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

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

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

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

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

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

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

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

            // Get the bookmark cursor for this ID and move it to the first row.
            Cursor bookmarkCursor = bookmarksDatabaseHelper.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(), resources.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(), resources.getString(R.string.edit_bookmark));
            }

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

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

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

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

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

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

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

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

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

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

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

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

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

        // 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 gone.  This prevents the display of the `WebView` while it is still loading.
                                    if (progressBar.getVisibility() == View.GONE) {
                                        mainWebView.setVisibility(View.VISIBLE);
                                    }
                                };

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

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

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

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

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

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

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

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

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

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

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

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

                /* SYSTEM_UI_FLAG_FULLSCREEN hides the status bar at the top of the screen.
                 * SYSTEM_UI_FLAG_HIDE_NAVIGATION hides the navigation bar on the bottom or right of the screen.
                 * SYSTEM_UI_FLAG_IMMERSIVE_STICKY makes the status and navigation bars translucent and automatically re-hides them after they are shown.
                 */
                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.google_app_id), getString(R.string.ad_unit_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_unit_id));
                }
            }

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

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

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

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

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

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

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

                        // Show the download location permission alert dialog.  The permission will be requested when the the dialog is closed.
                        downloadLocationPermissionDialogFragment.show(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 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 a handle for the `Runtime`.
        privacyBrowserRuntime = Runtime.getRuntime();

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

                    // Make it so.
                    startActivity(emailIntent);

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

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

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

                    // Make it so.
                    startActivity(dialIntent);

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

                // Display the HTTP authentication dialog.
                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.
                    // The formatted URL string must be updated at the beginning of the load, so that if the user toggles JavaScript during the load the new website is reloaded.
                    formattedUrlString = url;

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

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

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

                        // Reset `navigatingHistory`.
                        navigatingHistory = false;

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

                    // 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) {
                // Reset the wide view port if it has been turned off by the waiting for Orbot message.
                if (!waitingForOrbot) {
                    // Only use a wide view port if the URL starts with `http`, not for `file://` and `content://`.
                    mainWebView.getSettings().setUseWideViewPort(url.startsWith("http"));
                }

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

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

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

                // 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 the formatted URL string.  Getting the URL from the WebView instead of using the one provided by `onPageFinished` makes websites like YouTube function correctly.
                        formattedUrlString = mainWebView.getUrl();

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

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

                    // Store the SSL certificate so it can be accessed from `ViewSslCertificateDialog` and `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.
                    // Also ignore if changes in the user agent causes an error while navigating history.
                    if (pinnedDomainSslCertificate && !ignorePinnedSslCertificate && navigatingHistory) {
                        // 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));
                }
            }
        });

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

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

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

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

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

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

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

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

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

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

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

        // Load the URL.
        loadUrl(formattedUrlString);

        // 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")) {
            // Disable the wide view port so that the waiting for Orbot text is displayed correctly.
            mainWebView.getSettings().setUseWideViewPort(false);

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

        if (displayingFullScreenVideo) {
            // 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);

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

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

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

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

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

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

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

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

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

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

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

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

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

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

        return true;
    }

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

        // Display the menu.
        return true;
    }

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

        // 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();

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

                                        // Setup a runnable to manually delete the DOM storage files and directories.
                                        Runnable deleteDomStorageRunnable = () -> {
                                            try {
                                                // A `String[]` 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.
                                            }
                                        };

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

            // Form data can be remove once the minimum API >= 26.
            case R.id.clear_form_data:
                Snackbar.make(findViewById(R.id.main_webview), R.string.form_data_deleted, Snackbar.LENGTH_LONG)
                        .setAction(R.string.undo, v -> {
                            // Do nothing because everything will be handled by `onDismissed()` below.
                        })
                        .addCallback(new Snackbar.Callback() {
                            @Override
                            public void onDismissed(Snackbar snackbar, int event) {
                                switch (event) {
                                    // The user pushed the `Undo` button.
                                    case Snackbar.Callback.DISMISS_EVENT_ACTION:
                                        // Do nothing.
                                        break;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

            case R.id.swipe_to_refresh:
                // Toggle swipe to refresh.
                swipeRefreshLayout.setEnabled(!swipeRefreshLayout.isEnabled());
                return true;

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

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

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

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

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

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

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

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

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

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

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

            case R.id.find_on_page:
                // Hide the URL app bar.
                supportAppBar.setVisibility(View.GONE);

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

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

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

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

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

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

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

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