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

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

package com.stoutner.privacybrowser.activities;

import android.Manifest;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.DownloadManager;
import android.app.SearchManager;
import android.content.ActivityNotFoundException;
import android.content.BroadcastReceiver;
import android.content.ClipData;
import android.content.ClipboardManager;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.SharedPreferences;
import android.content.pm.PackageManager;
import android.content.res.Configuration;
import android.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.text.Editable;
import android.text.Spanned;
import android.text.TextWatcher;
import android.text.style.ForegroundColorSpan;
import android.util.Patterns;
import android.view.ContextMenu;
import android.view.GestureDetector;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.view.inputmethod.InputMethodManager;
import android.webkit.CookieManager;
import android.webkit.HttpAuthHandler;
import android.webkit.SslErrorHandler;
import android.webkit.ValueCallback;
import android.webkit.WebBackForwardList;
import android.webkit.WebChromeClient;
import android.webkit.WebResourceResponse;
import android.webkit.WebSettings;
import android.webkit.WebStorage;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.webkit.WebViewDatabase;
import android.widget.ArrayAdapter;
import android.widget.CursorAdapter;
import android.widget.EditText;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.RadioButton;
import android.widget.RelativeLayout;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.ActionBarDrawerToggle;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import androidx.core.view.GravityCompat;
import androidx.drawerlayout.widget.DrawerLayout;
import androidx.fragment.app.DialogFragment;
import androidx.fragment.app.FragmentManager;
import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
import androidx.viewpager.widget.ViewPager;

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

import com.stoutner.privacybrowser.BuildConfig;
import com.stoutner.privacybrowser.R;
import com.stoutner.privacybrowser.adapters.WebViewPagerAdapter;
import com.stoutner.privacybrowser.asynctasks.GetHostIpAddresses;
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.DownloadFileDialog;
import com.stoutner.privacybrowser.dialogs.DownloadImageDialog;
import com.stoutner.privacybrowser.dialogs.DownloadLocationPermissionDialog;
import com.stoutner.privacybrowser.dialogs.EditBookmarkDialog;
import com.stoutner.privacybrowser.dialogs.EditBookmarkFolderDialog;
import com.stoutner.privacybrowser.dialogs.HttpAuthenticationDialog;
import com.stoutner.privacybrowser.dialogs.PinnedMismatchDialog;
import com.stoutner.privacybrowser.dialogs.SslCertificateErrorDialog;
import com.stoutner.privacybrowser.dialogs.UrlHistoryDialog;
import com.stoutner.privacybrowser.dialogs.ViewSslCertificateDialog;
import com.stoutner.privacybrowser.fragments.WebViewTabFragment;
import com.stoutner.privacybrowser.helpers.AdHelper;
import com.stoutner.privacybrowser.helpers.BlockListHelper;
import com.stoutner.privacybrowser.helpers.BookmarksDatabaseHelper;
import com.stoutner.privacybrowser.helpers.CheckPinnedMismatchHelper;
import com.stoutner.privacybrowser.helpers.DomainsDatabaseHelper;
import com.stoutner.privacybrowser.helpers.OrbotProxyHelper;
import com.stoutner.privacybrowser.views.NestedScrollWebView;

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;

// TODO.  Store up reloads for tabs that are not visible.
// TODO.  New tabs are white in dark mode.

// 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,
        DownloadFileDialog.DownloadFileListener, DownloadImageDialog.DownloadImageListener, DownloadLocationPermissionDialog.DownloadLocationPermissionDialogListener, EditBookmarkDialog.EditBookmarkListener,
        EditBookmarkFolderDialog.EditBookmarkFolderListener, HttpAuthenticationDialog.HttpAuthenticationListener, NavigationView.OnNavigationItemSelectedListener, WebViewTabFragment.NewTabListener,
        PinnedMismatchDialog.PinnedMismatchListener, SslCertificateErrorDialog.SslCertificateErrorListener, UrlHistoryDialog.UrlHistoryListener {

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

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

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

    // The WebView pager adapter is accessed from `PinnedMismatchDialog`.  It is also used in `onCreate()`, `onResume()`, and `addTab()`.
    public static WebViewPagerAdapter webViewPagerAdapter;

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

    // The load URL on restart variables are public static so they can be accessed from `BookmarksActivity`.  They are used in `onRestart()`.
    public static boolean loadUrlOnRestart;
    public static String urlToLoadOnRestart;

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

    // The blocklist 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;

    // `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;

    // 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;



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

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

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

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

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

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

    // The options menu is set in `onCreateOptionsMenu()` and used in `onOptionsItemSelected()`, `updatePrivacyIcons()`, and `initializeWebView()`.
    private Menu optionsMenu;

    // TODO.  This could probably be removed.
    // The blocklist helper is used in `onCreate()` and `WebViewPagerAdapter`.
    private BlockListHelper blockListHelper;

    // The blocklists are populated in `onCreate()` and accessed from `WebViewPagerAdapter`.
    private ArrayList<List<String[]>> easyList;
    private ArrayList<List<String[]>> easyPrivacy;
    private ArrayList<List<String[]>> fanboysAnnoyanceList;
    private ArrayList<List<String[]>> fanboysSocialList;
    private ArrayList<List<String[]>> ultraPrivacy;

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

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

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

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

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

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

    // Hide app bar is used in `onCreate()` and `applyAppSettings()`.
    private boolean hideAppBar;  // TODO.

    // `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;  // TODO.

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

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

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

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

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

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

    // 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;  // TODO.

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

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

    // `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()`, `onRequestPermissionResult()` and `initializeWebView()`.
    private String downloadUrl;
    private String downloadContentDisposition;
    private long downloadContentLength;

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

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

    @Override
    // Remove the warning about needing to override `performClick()` when using an `OnTouchListener` with `WebView`.
    @SuppressLint("ClickableViewAccessibility")
    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_framelayout);

        // Get a handle for the input method.
        InputMethodManager inputMethodManager = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);

        // Remove the lint warning below that the input method manager might be null.
        assert inputMethodManager != null;

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

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

        // Get a handle for the action bar.
        ActionBar actionBar = getSupportActionBar();

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

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

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

        // Get handles for the URL views.
        EditText urlEditText = findViewById(R.id.url_edittext);

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

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

        // Set the go button on the keyboard to load the URL in `urlTextBox`.
        urlEditText.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 the Orbot status and the waiting for Orbot trackers.
        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 the waiting for Orbot status.
                    waitingForOrbot = false;

                    // 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 = "";
                        }

                        // Load the completed search URL.
                        loadUrl(searchURL + encodedUrlString);
                    } else if (launchingIntentUriData != null){  // Check to see if the intent contains a new URL.
                        // Load the URL from the intent.
                        loadUrl(launchingIntentUriData.toString());
                    } else {  // The is no URL in the intent.
                        // Load the homepage.
                        loadUrl(homepage);
                    }
                }
            }
        };

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

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

        // Parse the block lists.
        easyList = blockListHelper.parseBlockList(getAssets(), "blocklists/easylist.txt");
        easyPrivacy = blockListHelper.parseBlockList(getAssets(), "blocklists/easyprivacy.txt");
        fanboysAnnoyanceList = blockListHelper.parseBlockList(getAssets(), "blocklists/fanboy-annoyance.txt");
        fanboysSocialList = blockListHelper.parseBlockList(getAssets(), "blocklists/fanboy-social.txt");
        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 handles for views that need to be modified.
        DrawerLayout drawerLayout = findViewById(R.id.drawerlayout);
        NavigationView navigationView = findViewById(R.id.navigationview);
        TabLayout tabLayout = findViewById(R.id.tablayout);
        SwipeRefreshLayout swipeRefreshLayout = findViewById(R.id.swiperefreshlayout);
        ViewPager webViewPager = findViewById(R.id.webviewpager);
        ListView bookmarksListView = findViewById(R.id.bookmarks_drawer_listview);
        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);
        EditText findOnPageEditText = findViewById(R.id.find_on_page_edittext);

        // Listen for touches on the navigation menu.
        navigationView.setNavigationItemSelectedListener(this);

        // Get handles for the navigation menu and the back and forward menu items.  The menu is zero-based.
        Menu navigationMenu = navigationView.getMenu();
        MenuItem navigationCloseTabMenuItem = navigationMenu.getItem(0);
        MenuItem navigationBackMenuItem = navigationMenu.getItem(3);
        MenuItem navigationForwardMenuItem = navigationMenu.getItem(4);
        MenuItem navigationHistoryMenuItem = navigationMenu.getItem(5);
        MenuItem navigationRequestsMenuItem = navigationMenu.getItem(6);

        // Initialize the web view pager adapter.
        webViewPagerAdapter = new WebViewPagerAdapter(getSupportFragmentManager());

        // Set the pager adapter on the web view pager.
        webViewPager.setAdapter(webViewPagerAdapter);

        // Store up to 100 tabs in memory.
        webViewPager.setOffscreenPageLimit(100);

        // Update the web view pager every time a tab is modified.
        webViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
                // Do nothing.
            }

            @Override
            public void onPageSelected(int position) {
                // Set the current WebView.
                setCurrentWebView(position);

                // Select the corresponding tab if it does not match the currently selected page.  This will happen if the page was scrolled via swiping in the view pager.
                if (tabLayout.getSelectedTabPosition() != position) {
                    // Get a handle for the corresponding tab.
                    TabLayout.Tab correspondingTab = tabLayout.getTabAt(position);

                    // Assert that the corresponding tab is not null.
                    assert correspondingTab != null;

                    // Select the corresponding tab.
                    correspondingTab.select();
                }
            }

            @Override
            public void onPageScrollStateChanged(int state) {
                // Do nothing.
            }
        });

        // Display the View SSL Certificate dialog when the currently selected tab is reselected.
        tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                // Select the same page in the view pager.
                webViewPager.setCurrentItem(tab.getPosition());
            }

            @Override
            public void onTabUnselected(TabLayout.Tab tab) {
                // Do nothing.
            }

            @Override
            public void onTabReselected(TabLayout.Tab tab) {
                // Instantiate the View SSL Certificate dialog.
                DialogFragment viewSslCertificateDialogFragment = ViewSslCertificateDialog.displayDialog(currentWebView.getWebViewFragmentId());

                // Display the View SSL Certificate dialog.
                viewSslCertificateDialogFragment.show(getSupportFragmentManager(), getString(R.string.view_ssl_certificate));
            }
        });

        // Add the first tab.
        addTab(null);

        // 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.
        // The deprecated `getResources().getDrawable()` must be used until the minimum API >= 21 and and `getResources().getColor()` must be used until the minimum API >= 23.
        if (darkTheme) {
            launchBookmarksActivityFab.setImageDrawable(getResources().getDrawable(R.drawable.bookmarks_dark));
            createBookmarkFolderFab.setImageDrawable(getResources().getDrawable(R.drawable.create_folder_dark));
            createBookmarkFab.setImageDrawable(getResources().getDrawable(R.drawable.create_bookmark_dark));
            bookmarksListView.setBackgroundColor(getResources().getColor(R.color.gray_850));
        } else {
            launchBookmarksActivityFab.setImageDrawable(getResources().getDrawable(R.drawable.bookmarks_light));
            createBookmarkFolderFab.setImageDrawable(getResources().getDrawable(R.drawable.create_folder_light));
            createBookmarkFab.setImageDrawable(getResources().getDrawable(R.drawable.create_bookmark_light));
            bookmarksListView.setBackgroundColor(getResources().getColor(R.color.white));
        }

        // Set the launch bookmarks activity FAB to launch the bookmarks activity.
        launchBookmarksActivityFab.setOnClickListener(v -> {
            // Get a copy of the favorite icon bitmap.
            Bitmap favoriteIconBitmap = currentWebView.getFavoriteOrDefaultIcon();

            // Create a favorite icon byte array output stream.
            ByteArrayOutputStream favoriteIconByteArrayOutputStream = new ByteArrayOutputStream();

            // Convert the favorite icon bitmap to a byte array.  `0` is for lossless compression (the only option for a PNG).
            favoriteIconBitmap.compress(Bitmap.CompressFormat.PNG, 0, favoriteIconByteArrayOutputStream);

            // Convert the favorite icon byte array stream to a byte array.
            byte[] favoriteIconByteArray = favoriteIconByteArrayOutputStream.toByteArray();

            // Create an intent to launch the bookmarks activity.
            Intent bookmarksIntent = new Intent(getApplicationContext(), BookmarksActivity.class);

            // Add the extra information to the intent.
            bookmarksIntent.putExtra("current_url", currentWebView.getUrl());
            bookmarksIntent.putExtra("current_title", currentWebView.getTitle());
            bookmarksIntent.putExtra("current_folder", currentBookmarksFolder);
            bookmarksIntent.putExtra("favorite_icon_byte_array", favoriteIconByteArray);

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

        // Set the create new bookmark folder FAB to display an alert dialog.
        createBookmarkFolderFab.setOnClickListener(v -> {
            // Create a create bookmark folder dialog.
            DialogFragment createBookmarkFolderDialog = CreateBookmarkFolderDialog.createBookmarkFolder(currentWebView.getFavoriteOrDefaultIcon());

            // Show the create bookmark folder dialog.
            createBookmarkFolderDialog.show(getSupportFragmentManager(), getString(R.string.create_folder));
        });

        // Set the create new bookmark FAB to display an alert dialog.
        createBookmarkFab.setOnClickListener(view -> {
            // Instantiate the create bookmark dialog.
            DialogFragment createBookmarkDialog = CreateBookmarkDialog.createBookmark(currentWebView.getUrl(), currentWebView.getTitle(), currentWebView.getFavoriteOrDefaultIcon());

            // Display the create bookmark dialog.
            createBookmarkDialog.show(getSupportFragmentManager(), getString(R.string.create_bookmark));
        });

        // 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`.
                currentWebView.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.
                inputMethodManager.hideSoftInputFromWindow(currentWebView.getWindowToken(), 0);

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

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

        // The swipe to refresh circle doesn't always hide itself completely unless it is moved up 10 pixels.
        swipeRefreshLayout.setProgressViewOffset(false, swipeRefreshLayout.getProgressViewStartOffset() - 10, swipeRefreshLayout.getProgressViewEndOffset());

        // Set the swipe to refresh color according to the theme.
        if (darkTheme) {
            swipeRefreshLayout.setColorSchemeResources(R.color.blue_800);
            swipeRefreshLayout.setProgressBackgroundColorSchemeResource(R.color.gray_850);
        } else {
            swipeRefreshLayout.setColorSchemeResources(R.color.blue_500);
        }

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

        // 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 navigation menu items.
                    navigationCloseTabMenuItem.setEnabled(tabLayout.getTabCount() > 1);
                    navigationBackMenuItem.setEnabled(currentWebView.canGoBack());
                    navigationForwardMenuItem.setEnabled(currentWebView.canGoForward());
                    navigationHistoryMenuItem.setEnabled((currentWebView.canGoBack() || currentWebView.canGoForward()));
                    navigationRequestsMenuItem.setTitle(getString(R.string.requests) + " - " + currentWebView.getRequestsCount(NestedScrollWebView.BLOCKED_REQUESTS));

                    // Hide the keyboard (if displayed).
                    inputMethodManager.hideSoftInputFromWindow(currentWebView.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.
                    urlEditText.clearFocus();
                    currentWebView.clearFocus();
                }
            }
        });

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

        // 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);

        // 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.
        firstPartyCookiesEnabled = false;

        // Inflate a bare WebView to get the default user agent.  It is not used to render content on the screen.
        @SuppressLint("InflateParams") View webViewLayout = getLayoutInflater().inflate(R.layout.bare_webview, null, false);

        // Get a handle for the WebView.
        WebView bareWebView = webViewLayout.findViewById(R.id.bare_webview);

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

        // Destroy the bare WebView.
        bareWebView.destroy();
    }

    @Override
    protected void onNewIntent(Intent intent) {
        // Get the information from the intent.
        String intentAction = intent.getAction();
        Uri intentUriData = intent.getData();

        // Only process the URI if it contains data.  If the user pressed the desktop icon after the app was already running the URI will be null.
        if (intentUriData != null) {
            // Sets the new intent as the activity intent, which replaces the one that originally started the app.
            setIntent(intent);

            // Add a new tab.
            addTab(null);

            // Create a URL string.
            String url;

            // 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.
                url = searchURL + encodedUrlString;
            } else {  // The intent should contain a URL.
                // Set the intent data as the URL.
                url = intentUriData.toString();
            }

            // Load the URL.
            loadUrl(url);

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

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

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

            // Clear the keyboard if displayed and remove the focus on the urlTextBar if it has it.
            currentWebView.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 to handle changes to night mode and displaying of images.
            if (reloadOnRestart) {
                // Reload the WebViews.
                for (int i = 0; i < webViewPagerAdapter.getCount(); i++) {
                    // Get the WebView tab fragment.
                    WebViewTabFragment webViewTabFragment = webViewPagerAdapter.getPageFragment(i);

                    // Get the fragment view.
                    View fragmentView = webViewTabFragment.getView();

                    // Only reload the WebViews if they exist.
                    if (fragmentView != null) {
                        // Get the nested scroll WebView from the tab fragment.
                        NestedScrollWebView nestedScrollWebView = fragmentView.findViewById(R.id.nestedscroll_webview);

                        // Reload the WebView.  This doesn't seem to work if for WebViews that aren't visible.
                        nestedScrollWebView.reload();
                    }
                }

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

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

        // TODO apply to all the tabs.
        // Apply the domain settings if returning from the Domains activity.
        if (reapplyDomainSettingsOnRestart) {
            // Reset the current domain name so the domain settings will be reapplied.
            currentWebView.resetCurrentDomainName();

            // Reapply the domain settings.
            applyDomainSettings(currentWebView, currentWebView.getUrl(), false, true);  // TODO.

            // Reset the reapply domain settings on restart tracker.
            reapplyDomainSettingsOnRestart = false;
        }

        // Load the URL on restart (used when loading a bookmark.
        if (loadUrlOnRestart) {
            // Load the specified URL.
            loadUrl(urlToLoadOnRestart);

            // Reset the load on restart tracker.
            loadUrlOnRestart = false;
        }

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

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

            // Reload the bookmarks drawer.
            loadBookmarksFolder();

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

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

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

        for (int i = 0; i < webViewPagerAdapter.getCount(); i++) {
            // Get the WebView tab fragment.
            WebViewTabFragment webViewTabFragment = webViewPagerAdapter.getPageFragment(i);

            // Get the fragment view.
            View fragmentView = webViewTabFragment.getView();

            // Only resume the WebViews if they exist (they won't when the app is first created).
            if (fragmentView != null) {
                // Get the nested scroll WebView from the tab fragment.
                NestedScrollWebView nestedScrollWebView = fragmentView.findViewById(R.id.nestedscroll_webview);

                // Resume the nested scroll WebView JavaScript timers.
                nestedScrollWebView.resumeTimers();

                // Resume the nested scroll WebView.
                nestedScrollWebView.onResume();
            }
        }

        // 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.
            currentWebView.getSettings().setUseWideViewPort(false);

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

        if (displayingFullScreenVideo || inFullScreenBrowsingMode) {
            // Get a handle for the root frame layouts.
            FrameLayout rootFrameLayout = findViewById(R.id.root_framelayout);

            // Remove the translucent status flag.  This is necessary so the root frame layout can fill the entire screen.
            getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);

            /* Hide the system bars.
             * SYSTEM_UI_FLAG_FULLSCREEN hides the status bar at the top of the screen.
             * SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN makes the root frame layout fill the area that is normally reserved for the status bar.
             * 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.
             */
            rootFrameLayout.setSystemUiVisibility(View.SYSTEM_UI_FLAG_FULLSCREEN | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION |
                    View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);
        } else if (BuildConfig.FLAVOR.contentEquals("free")) {  // Resume the adView for the free flavor.
            // Resume the ad.
            AdHelper.resumeAd(findViewById(R.id.adview));
        }
    }

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

        for (int i = 0; i < webViewPagerAdapter.getCount(); i++) {
            // Get the WebView tab fragment.
            WebViewTabFragment webViewTabFragment = webViewPagerAdapter.getPageFragment(i);

            // Get the fragment view.
            View fragmentView = webViewTabFragment.getView();

            // Only pause the WebViews if they exist (they won't when the app is first created).
            if (fragmentView != null) {
                // Get the nested scroll WebView from the tab fragment.
                NestedScrollWebView nestedScrollWebView = fragmentView.findViewById(R.id.nestedscroll_webview);

                // Pause the nested scroll WebView.
                nestedScrollWebView.onPause();

                // Pause the nested scroll WebView JavaScript timers.
                nestedScrollWebView.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);

        // Store a handle for the options menu so it can be used by `onOptionsItemSelected()` and `updatePrivacyIcons()`.
        optionsMenu = 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.
        MenuItem 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);

        // Disable the clear form data menu item if the API >= 26 so that the status of the main Clear Data is calculated correctly.
        clearFormDataMenuItem.setEnabled(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.
        boolean 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 (currentWebView != null && currentWebView.getProgress() != 100) {
            // 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 firstPartyCookiesMenuItem = menu.findItem(R.id.toggle_first_party_cookies);
        MenuItem thirdPartyCookiesMenuItem = menu.findItem(R.id.toggle_third_party_cookies);
        MenuItem domStorageMenuItem = menu.findItem(R.id.toggle_dom_storage);
        MenuItem saveFormDataMenuItem = 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);

        // Get a handle for the cookie manager.
        CookieManager cookieManager = CookieManager.getInstance();

        // Initialize the current user agent string and the font size.
        String currentUserAgent = getString(R.string.user_agent_privacy_browser);
        int fontSize = 100;

        // Set items that require the current web view to be populated.  It will be null when the program is first opened, as `onPrepareOptionsMenu()` is called before the first WebView is initialized.
        if (currentWebView != null) {
            // Set the add or edit domain text.
            if (currentWebView.getDomainSettingsApplied()) {
                addOrEditDomain.setTitle(R.string.edit_domain_settings);
            } else {
                addOrEditDomain.setTitle(R.string.add_domain_settings);
            }

            // Get the current user agent from the WebView.
            currentUserAgent = currentWebView.getSettings().getUserAgentString();

            // Get the current font size from the
            fontSize = currentWebView.getSettings().getTextZoom();

            // Set the status of the menu item checkboxes.
            domStorageMenuItem.setChecked(currentWebView.getSettings().getDomStorageEnabled());
            saveFormDataMenuItem.setChecked(currentWebView.getSettings().getSaveFormData());  // Form data can be removed once the minimum API >= 26.
            easyListMenuItem.setChecked(currentWebView.isBlocklistEnabled(NestedScrollWebView.EASY_LIST));
            easyPrivacyMenuItem.setChecked(currentWebView.isBlocklistEnabled(NestedScrollWebView.EASY_PRIVACY));
            fanboysAnnoyanceListMenuItem.setChecked(currentWebView.isBlocklistEnabled(NestedScrollWebView.FANBOYS_ANNOYANCE_LIST));
            fanboysSocialBlockingListMenuItem.setChecked(currentWebView.isBlocklistEnabled(NestedScrollWebView.FANBOYS_SOCIAL_BLOCKING_LIST));
            ultraPrivacyMenuItem.setChecked(currentWebView.isBlocklistEnabled(NestedScrollWebView.ULTRA_PRIVACY));
            blockAllThirdPartyRequestsMenuItem.setChecked(currentWebView.isBlocklistEnabled(NestedScrollWebView.THIRD_PARTY_REQUESTS));
            swipeToRefreshMenuItem.setChecked(currentWebView.getSwipeToRefresh());
            displayImagesMenuItem.setChecked(currentWebView.getSettings().getLoadsImagesAutomatically());
            nightModeMenuItem.setChecked(currentWebView.getNightMode());

            // Initialize the display names for the blocklists with the number of blocked requests.
            blocklistsMenuItem.setTitle(getString(R.string.blocklists) + " - " + currentWebView.getRequestsCount(NestedScrollWebView.BLOCKED_REQUESTS));
            easyListMenuItem.setTitle(currentWebView.getRequestsCount(NestedScrollWebView.EASY_LIST) + " - " + getString(R.string.easylist));
            easyPrivacyMenuItem.setTitle(currentWebView.getRequestsCount(NestedScrollWebView.EASY_PRIVACY) + " - " + getString(R.string.easyprivacy));
            fanboysAnnoyanceListMenuItem.setTitle(currentWebView.getRequestsCount(NestedScrollWebView.FANBOYS_ANNOYANCE_LIST) + " - " + getString(R.string.fanboys_annoyance_list));
            fanboysSocialBlockingListMenuItem.setTitle(currentWebView.getRequestsCount(NestedScrollWebView.FANBOYS_SOCIAL_BLOCKING_LIST) + " - " + getString(R.string.fanboys_social_blocking_list));
            ultraPrivacyMenuItem.setTitle(currentWebView.getRequestsCount(NestedScrollWebView.ULTRA_PRIVACY) + " - " + getString(R.string.ultraprivacy));
            blockAllThirdPartyRequestsMenuItem.setTitle(currentWebView.getRequestsCount(NestedScrollWebView.THIRD_PARTY_REQUESTS) + " - " + getString(R.string.block_all_third_party_requests));

            // Only modify third-party cookies if the API >= 21.
            if (Build.VERSION.SDK_INT >= 21) {
                // Set the status of the third-party cookies checkbox.
                thirdPartyCookiesMenuItem.setChecked(cookieManager.acceptThirdPartyCookies(currentWebView));

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

            // Enable DOM Storage if JavaScript is enabled.
            domStorageMenuItem.setEnabled(currentWebView.getSettings().getJavaScriptEnabled());
        }

        // Set the status of the menu item checkboxes.
        firstPartyCookiesMenuItem.setChecked(firstPartyCookiesEnabled);
        proxyThroughOrbotMenuItem.setChecked(proxyThroughOrbot);

        // 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) {
            // Get the WebView database.
            WebViewDatabase webViewDatabase = WebViewDatabase.getInstance(this);

            // Enable the clear form data menu item if there is anything to clear.
            clearFormDataMenuItem.setEnabled(webViewDatabase.hasFormData());
        }

        // 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 menu item if Fanboy's Annoyance List is checked.
        fanboysSocialBlockingListMenuItem.setEnabled(!fanboysAnnoyanceListMenuItem.isChecked());

        // 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);
        }

        // Instantiate the font size title and the selected font size menu item.
        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) {
        // Reenter full screen browsing mode if it was interrupted by the options menu.  <https://redmine.stoutner.com/issues/389>
        if (inFullScreenBrowsingMode) {
            // Remove the translucent status flag.  This is necessary so the root frame layout can fill the entire screen.
            getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);

            FrameLayout rootFrameLayout = findViewById(R.id.root_framelayout);

            /* Hide the system bars.
             * SYSTEM_UI_FLAG_FULLSCREEN hides the status bar at the top of the screen.
             * SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN makes the root frame layout fill the area that is normally reserved for the status bar.
             * 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.
             */
            rootFrameLayout.setSystemUiVisibility(View.SYSTEM_UI_FLAG_FULLSCREEN | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION |
                    View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);
        }

        // Get the selected menu item ID.
        int menuItemId = menuItem.getItemId();

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

        // Get a handle for the cookie manager.
        CookieManager cookieManager = CookieManager.getInstance();

        // Run the commands that correlate to the selected menu item.
        switch (menuItemId) {
            case R.id.toggle_javascript:
                // Toggle the JavaScript status.
                currentWebView.getSettings().setJavaScriptEnabled(!currentWebView.getSettings().getJavaScriptEnabled());

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

                // Display a `Snackbar`.
                if (currentWebView.getSettings().getJavaScriptEnabled()) {  // JavaScrip is enabled.
                    Snackbar.make(findViewById(R.id.webviewpager), 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.webviewpager), R.string.javascript_disabled, Snackbar.LENGTH_SHORT).show();
                } else {  // Privacy mode.
                    Snackbar.make(findViewById(R.id.webviewpager), R.string.privacy_mode, Snackbar.LENGTH_SHORT).show();
                }

                // Reload the current WebView.
                currentWebView.reload();
                return true;

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

                    // TODO.  Move these to `putExtra`.  The certificate can be stored as strings.
                    // Store the current SSL certificate and IP addresses in the domains activity.
                    DomainsActivity.currentSslCertificate = currentWebView.getCertificate();
                    DomainsActivity.currentIpAddresses = currentWebView.getCurrentIpAddresses();

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

                    // Add the extra information to the intent.
                    domainsIntent.putExtra("load_domain", currentWebView.getDomainSettingsDatabaseId());
                    domainsIntent.putExtra("close_on_back", true);
                    domainsIntent.putExtra("current_url", currentWebView.getUrl());

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

                    // Get the current domain
                    Uri currentUri = Uri.parse(currentWebView.getUrl());
                    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);

                    // TODO.  Move these to `putExtra`.  The certificate can be stored as strings.
                    // Store the current SSL certificate and IP addresses in the domains activity.
                    DomainsActivity.currentSslCertificate = currentWebView.getCertificate();
                    DomainsActivity.currentIpAddresses = currentWebView.getCurrentIpAddresses();

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

                    // Add the extra information to the intent.
                    domainsIntent.putExtra("load_domain", newDomainDatabaseId);
                    domainsIntent.putExtra("close_on_back", true);
                    domainsIntent.putExtra("current_url", currentWebView.getUrl());

                    // 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.webviewpager), R.string.first_party_cookies_enabled, Snackbar.LENGTH_SHORT).show();
                } else if (currentWebView.getSettings().getJavaScriptEnabled()) {  // JavaScript is still enabled.
                    Snackbar.make(findViewById(R.id.webviewpager), R.string.first_party_cookies_disabled, Snackbar.LENGTH_SHORT).show();
                } else {  // Privacy mode.
                    Snackbar.make(findViewById(R.id.webviewpager), R.string.privacy_mode, Snackbar.LENGTH_SHORT).show();
                }

                // Reload the current WebView.
                currentWebView.reload();
                return true;

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

                    // Update the menu checkbox.
                    menuItem.setChecked(cookieManager.acceptThirdPartyCookies(currentWebView));

                    // Display a snackbar.
                    if (cookieManager.acceptThirdPartyCookies(currentWebView)) {
                        Snackbar.make(findViewById(R.id.webviewpager), R.string.third_party_cookies_enabled, Snackbar.LENGTH_SHORT).show();
                    } else {
                        Snackbar.make(findViewById(R.id.webviewpager), R.string.third_party_cookies_disabled, Snackbar.LENGTH_SHORT).show();
                    }

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

            case R.id.toggle_dom_storage:
                // Toggle the status of domStorageEnabled.
                currentWebView.getSettings().setDomStorageEnabled(!currentWebView.getSettings().getDomStorageEnabled());

                // Update the menu checkbox.
                menuItem.setChecked(currentWebView.getSettings().getDomStorageEnabled());

                // Update the privacy icon.  `true` refreshes the app bar icons.
                updatePrivacyIcons(true);

                // Display a snackbar.
                if (currentWebView.getSettings().getDomStorageEnabled()) {
                    Snackbar.make(findViewById(R.id.webviewpager), R.string.dom_storage_enabled, Snackbar.LENGTH_SHORT).show();
                } else {
                    Snackbar.make(findViewById(R.id.webviewpager), R.string.dom_storage_disabled, Snackbar.LENGTH_SHORT).show();
                }

                // Reload the current WebView.
                currentWebView.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.
                currentWebView.getSettings().setSaveFormData(!currentWebView.getSettings().getSaveFormData());

                // Update the menu checkbox.
                menuItem.setChecked(currentWebView.getSettings().getSaveFormData());

                // Display a snackbar.
                if (currentWebView.getSettings().getSaveFormData()) {
                    Snackbar.make(findViewById(R.id.webviewpager), R.string.form_data_enabled, Snackbar.LENGTH_SHORT).show();
                } else {
                    Snackbar.make(findViewById(R.id.webviewpager), R.string.form_data_disabled, Snackbar.LENGTH_SHORT).show();
                }

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

                // Reload the current WebView.
                currentWebView.reload();
                return true;

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

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

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

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

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

                                        // Setup a runnable to manually delete the DOM storage files and directories.
                                        Runnable deleteDomStorageRunnable = () -> {
                                            try {
                                                // Get a handle for the runtime.
                                                Runtime runtime = Runtime.getRuntime();

                                                // A string array must be used because the directory contains a space and `Runtime.exec` will otherwise not escape the string correctly.
                                                Process deleteLocalStorageProcess = runtime.exec(new String[]{"rm", "-rf", privateDataDirectoryString + "/app_webview/Local Storage/"});

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

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

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

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

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

            case R.id.easylist:
                // Toggle the EasyList status.
                currentWebView.enableBlocklist(NestedScrollWebView.EASY_LIST, !currentWebView.isBlocklistEnabled(NestedScrollWebView.EASY_LIST));

                // Update the menu checkbox.
                menuItem.setChecked(currentWebView.isBlocklistEnabled(NestedScrollWebView.EASY_LIST));

                // Reload the current WebView.
                currentWebView.reload();
                return true;

            case R.id.easyprivacy:
                // Toggle the EasyPrivacy status.
                currentWebView.enableBlocklist(NestedScrollWebView.EASY_PRIVACY, !currentWebView.isBlocklistEnabled(NestedScrollWebView.EASY_PRIVACY));

                // Update the menu checkbox.
                menuItem.setChecked(currentWebView.isBlocklistEnabled(NestedScrollWebView.EASY_PRIVACY));

                // Reload the current WebView.
                currentWebView.reload();
                return true;

            case R.id.fanboys_annoyance_list:
                // Toggle Fanboy's Annoyance List status.
                currentWebView.enableBlocklist(NestedScrollWebView.FANBOYS_ANNOYANCE_LIST, !currentWebView.isBlocklistEnabled(NestedScrollWebView.FANBOYS_ANNOYANCE_LIST));

                // Update the menu checkbox.
                menuItem.setChecked(currentWebView.isBlocklistEnabled(NestedScrollWebView.FANBOYS_ANNOYANCE_LIST));

                // Update the staus of Fanboy's Social Blocking List.
                MenuItem fanboysSocialBlockingListMenuItem = optionsMenu.findItem(R.id.fanboys_social_blocking_list);
                fanboysSocialBlockingListMenuItem.setEnabled(!currentWebView.isBlocklistEnabled(NestedScrollWebView.FANBOYS_ANNOYANCE_LIST));

                // Reload the current WebView.
                currentWebView.reload();
                return true;

            case R.id.fanboys_social_blocking_list:
                // Toggle Fanboy's Social Blocking List status.
                currentWebView.enableBlocklist(NestedScrollWebView.FANBOYS_SOCIAL_BLOCKING_LIST, !currentWebView.isBlocklistEnabled(NestedScrollWebView.FANBOYS_SOCIAL_BLOCKING_LIST));

                // Update the menu checkbox.
                menuItem.setChecked(currentWebView.isBlocklistEnabled(NestedScrollWebView.FANBOYS_SOCIAL_BLOCKING_LIST));

                // Reload the current WebView.
                currentWebView.reload();
                return true;

            case R.id.ultraprivacy:
                // Toggle the UltraPrivacy status.
                currentWebView.enableBlocklist(NestedScrollWebView.ULTRA_PRIVACY, !currentWebView.isBlocklistEnabled(NestedScrollWebView.ULTRA_PRIVACY));

                // Update the menu checkbox.
                menuItem.setChecked(currentWebView.isBlocklistEnabled(NestedScrollWebView.ULTRA_PRIVACY));

                // Reload the current WebView.
                currentWebView.reload();
                return true;

            case R.id.block_all_third_party_requests:
                //Toggle the third-party requests blocker status.
                currentWebView.enableBlocklist(NestedScrollWebView.THIRD_PARTY_REQUESTS, !currentWebView.isBlocklistEnabled(NestedScrollWebView.THIRD_PARTY_REQUESTS));

                // Update the menu checkbox.
                menuItem.setChecked(currentWebView.isBlocklistEnabled(NestedScrollWebView.THIRD_PARTY_REQUESTS));

                // Reload the current WebView.
                currentWebView.reload();
                return true;

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

                // Reload the current WebView.
                currentWebView.reload();
                return true;

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

                // Reload the current WebView.
                currentWebView.reload();
                return true;

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

                // Reload the current WebView.
                currentWebView.reload();
                return true;

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

                // Reload the current WebView.
                currentWebView.reload();
                return true;

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

                // Reload the current WebView.
                currentWebView.reload();
                return true;

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

                // Reload the current WebView.
                currentWebView.reload();
                return true;

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

                // Reload the current WebView.
                currentWebView.reload();
                return true;

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

                // Reload the current WebView.
                currentWebView.reload();
                return true;

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

                // Reload the current WebView.
                currentWebView.reload();
                return true;

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

                // Reload the current WebView.
                currentWebView.reload();
                return true;

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

                // Reload the current WebView.
                currentWebView.reload();
                return true;

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

                // Reload the current WebView.
                currentWebView.reload();
                return true;

            case R.id.user_agent_custom:
                // Update the user agent.
                currentWebView.getSettings().setUserAgentString(sharedPreferences.getString("custom_user_agent", getString(R.string.custom_user_agent_default_value)));

                // Reload the current WebView.
                currentWebView.reload();
                return true;

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

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

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

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

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

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

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

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

            case R.id.swipe_to_refresh:
                // Toggle the stored status of swipe to refresh.
                currentWebView.setSwipeToRefresh(!currentWebView.getSwipeToRefresh());

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

                // Update the swipe refresh layout.
                if (currentWebView.getSwipeToRefresh()) {  // Swipe to refresh is enabled.
                    if (Build.VERSION.SDK_INT >= 23) {  // For API >= 23, the status of the scroll refresh listener is continuously updated by the on scroll change listener.
                        // Only enable the swipe refresh layout if the WebView is scrolled to the top.
                        swipeRefreshLayout.setEnabled(currentWebView.getY() == 0);
                    } else {  // For API < 23, the swipe refresh layout is always enabled.
                        // Enable the swipe refresh layout.
                        swipeRefreshLayout.setEnabled(true);
                    }
                } else {  // Swipe to refresh is disabled.
                    // Disable the swipe refresh layout.
                    swipeRefreshLayout.setEnabled(false);
                }
                return true;

            case R.id.display_images:
                if (currentWebView.getSettings().getLoadsImagesAutomatically()) {  // Images are currently loaded automatically.
                    // Disable loading of images.
                    currentWebView.getSettings().setLoadsImagesAutomatically(false);

                    // Reload the website to remove existing images.
                    currentWebView.reload();
                } else {  // Images are not currently loaded automatically.
                    // Enable loading of images.  Missing images will be loaded without the need for a reload.
                    currentWebView.getSettings().setLoadsImagesAutomatically(true);
                }
                return true;

            case R.id.night_mode:
                // Toggle night mode.
                currentWebView.setNightMode(!currentWebView.getNightMode());

                // Enable or disable JavaScript according to night mode, the global preference, and any domain settings.
                if (currentWebView.getNightMode()) {  // Night mode is enabled, which requires JavaScript.
                    // Enable JavaScript.
                    currentWebView.getSettings().setJavaScriptEnabled(true);
                } else if (currentWebView.getDomainSettingsApplied()) {  // Night mode is disabled and domain settings are applied.  Set JavaScript according to the domain settings.
                    // Apply the JavaScript preference that was stored the last time domain settings were loaded.
                    currentWebView.getSettings().setJavaScriptEnabled(domainSettingsJavaScriptEnabled);  // TODO.
                } else {  // Night mode is disabled and domain settings are not applied.  Set JavaScript according to the global preference.
                    // Apply the JavaScript preference.
                    currentWebView.getSettings().setJavaScriptEnabled(sharedPreferences.getBoolean("javascript", false));
                }

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

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

            case R.id.find_on_page:
                // Get a handle for the views.
                Toolbar toolbar = findViewById(R.id.toolbar);
                LinearLayout findOnPageLinearLayout = findViewById(R.id.find_on_page_linearlayout);
                EditText findOnPageEditText = findViewById(R.id.find_on_page_edittext);

                // Hide the toolbar.
                toolbar.setVisibility(View.GONE);

                // Show the find on page linear layout.
                findOnPageLinearLayout.setVisibility(View.VISIBLE);

                // Display the keyboard.  The app must 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();

                    // Get a handle for the input method manager.
                    InputMethodManager inputMethodManager = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);

                    // Remove the lint warning below that the input method manager might be null.
                    assert inputMethodManager != null;

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

            case R.id.view_source:
                // Create an intent to launch the view source activity.
                Intent viewSourceIntent = new Intent(this, ViewSourceActivity.class);

                // Add the variables to the intent.
                viewSourceIntent.putExtra("user_agent", currentWebView.getSettings().getUserAgentString());
                viewSourceIntent.putExtra("current_url", currentWebView.getUrl());

                // Make it so.
                startActivity(viewSourceIntent);
                return true;

            case R.id.share_url:
                // Setup the share string.
                String shareString = currentWebView.getTitle() + " – " + currentWebView.getUrl();

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

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

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

                // Create a print document adapter form the current WebView.
                PrintDocumentAdapter printDocumentAdapter = currentWebView.createPrintDocumentAdapter();

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

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

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

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

            case R.id.add_to_homescreen:
                // Instantiate the create home screen shortcut dialog.
                DialogFragment createHomeScreenShortcutDialogFragment = CreateHomeScreenShortcutDialog.createDialog(currentWebView.getTitle(), currentWebView.getUrl(),
                        currentWebView.getFavoriteOrDefaultIcon());

                // Show the create home screen shortcut dialog.
                createHomeScreenShortcutDialogFragment.show(getSupportFragmentManager(), getString(R.string.create_shortcut));
                return true;

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

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

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

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

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

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

        // Run the commands that correspond to the selected menu item.
        switch (menuItemId) {
            case R.id.close_tab:
                // Get a handle for the tab layout and the view pager.
                TabLayout tabLayout = findViewById(R.id.tablayout);
                ViewPager webViewPager = findViewById(R.id.webviewpager);

                // Get the current tab number.
                int currentTabNumber = tabLayout.getSelectedTabPosition();

                // Delete the current tab.
                tabLayout.removeTabAt(currentTabNumber);

                // Delete the current page.  If the selected page number did not change during the delete, it will return true, meaning that the current WebView must be reset.
                if (webViewPagerAdapter.deletePage(currentTabNumber, webViewPager)) {
                    setCurrentWebView(currentTabNumber);
                }
                break;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

                // Clear the cache.
                if (clearEverything || sharedPreferences.getBoolean("clear_cache", true)) {
                    // Clear the cache from each WebView.
                    for (int i = 0; i < webViewPagerAdapter.getCount(); i++) {
                        // Get the WebView tab fragment.
                        WebViewTabFragment webViewTabFragment = webViewPagerAdapter.getPageFragment(i);

                        // Get the fragment view.
                        View fragmentView = webViewTabFragment.getView();

                        // Only clear the cache if the WebView exists.
                        if (fragmentView != null) {
                            // Get the nested scroll WebView from the tab fragment.
                            NestedScrollWebView nestedScrollWebView = fragmentView.findViewById(R.id.nestedscroll_webview);

                            // Clear the cache for this WebView.
                            nestedScrollWebView.clearCache(true);
                        }
                    }

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

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

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

                // Wipe out each WebView.
                for (int i = 0; i < webViewPagerAdapter.getCount(); i++) {
                    // Get the WebView tab fragment.
                    WebViewTabFragment webViewTabFragment = webViewPagerAdapter.getPageFragment(i);

                    // Get the fragment view.
                    View fragmentView = webViewTabFragment.getView();

                    // Only wipe out the WebView if it exists.
                    if (fragmentView != null) {
                        // Get the nested scroll WebView from the tab fragment.
                        NestedScrollWebView nestedScrollWebView = fragmentView.findViewById(R.id.nestedscroll_webview);

                        // Clear SSL certificate preferences for this WebView.
                        nestedScrollWebView.clearSslPreferences();

                        // Clear the back/forward history for this WebView.
                        nestedScrollWebView.clearHistory();

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

                // Clear the custom headers.
                customHeaders.clear();

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

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

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

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

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

            case R.id.back:
                if (currentWebView.canGoBack()) {
                    // Reset the current domain name so that navigation works if third-party requests are blocked.
                    currentWebView.resetCurrentDomainName();

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

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

            case R.id.forward:
                if (currentWebView.canGoForward()) {
                    // Reset the current domain name so that navigation works if third-party requests are blocked.
                    currentWebView.resetCurrentDomainName();

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

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

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

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

            case R.id.requests:
                // Populate the resource requests.
                RequestsActivity.resourceRequests = currentWebView.getResourceRequests();

                // Create an intent to launch the Requests activity.
                Intent requestsIntent = new Intent(this, RequestsActivity.class);

                // Add the block third-party requests status to the intent.
                requestsIntent.putExtra("block_all_third_party_requests", currentWebView.isBlocklistEnabled(NestedScrollWebView.THIRD_PARTY_REQUESTS));

                // Make it so.
                startActivity(requestsIntent);
                break;

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

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

                startActivity(downloadManagerIntent);
                break;

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

                // TODO.  Move these to `putExtra`.  The certificate can be stored as strings.
                // Store the current SSL certificate and IP addresses in the domains activity.
                DomainsActivity.currentSslCertificate = currentWebView.getCertificate();
                DomainsActivity.currentIpAddresses = currentWebView.getCurrentIpAddresses();

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

                // Add the extra information to the intent.
                domainsIntent.putExtra("current_url", currentWebView.getUrl());

                // Make it so.
                startActivity(domainsIntent);
                break;

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

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

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

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

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

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

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

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

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

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

        // Sync the state of the DrawerToggle after the default `onRestoreInstanceState()` has finished.  This creates the navigation drawer icon.
        actionBarDrawerToggle.syncState();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        // Run the default commands.
        super.onConfigurationChanged(newConfig);

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

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

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

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

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

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

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

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

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

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

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

                // Add a Load URL entry.
                menu.add(R.string.open_in_new_tab).setOnMenuItemClickListener((MenuItem item) -> {
                    // Add a new tab.
                    addTab(null);

                    // Load the URL.
                    loadUrl(linkUrl);
                    return false;
                });

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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