+ // Allow pinch to zoom.
+ nestedScrollWebView.getSettings().setBuiltInZoomControls(true);
+
+ // Hide zoom controls.
+ nestedScrollWebView.getSettings().setDisplayZoomControls(false);
+
+ // Don't allow mixed content (HTTP and HTTPS) on the same website.
+ nestedScrollWebView.getSettings().setMixedContentMode(WebSettings.MIXED_CONTENT_NEVER_ALLOW);
+
+ // Set the WebView to load in overview mode (zoomed out to the maximum width).
+ nestedScrollWebView.getSettings().setLoadWithOverviewMode(true);
+
+ // Explicitly disable geolocation.
+ nestedScrollWebView.getSettings().setGeolocationEnabled(false);
+
+ // Allow loading of file:// URLs. This is necessary for opening MHT web archives, which are copies into a temporary cache location.
+ nestedScrollWebView.getSettings().setAllowFileAccess(true);
+
+ // Create a double-tap gesture detector to toggle full-screen mode.
+ GestureDetector doubleTapGestureDetector = new GestureDetector(getApplicationContext(), new GestureDetector.SimpleOnGestureListener() {
+ // Override `onDoubleTap()`. All other events are handled using the default settings.
+ @Override
+ public boolean onDoubleTap(MotionEvent event) {
+ if (fullScreenBrowsingModeEnabled) { // Only process the double-tap if full screen browsing mode is enabled.
+ // Toggle the full screen browsing mode tracker.
+ inFullScreenBrowsingMode = !inFullScreenBrowsingMode;
+
+ // Toggle the full screen browsing mode.
+ if (inFullScreenBrowsingMode) { // Switch to full screen mode.
+ // Hide the app bar if specified.
+ if (hideAppBar) { // The app bar is hidden.
+ // Close the find on page bar if it is visible.
+ closeFindOnPage(null);
+
+ // Hide the tab linear layout.
+ tabsLinearLayout.setVisibility(View.GONE);
+
+ // Hide the action bar.
+ actionBar.hide();
+
+ // Set layout and scrolling parameters according to the position of the app bar.
+ if (bottomAppBar) { // The app bar is at the bottom.
+ // Reset the WebView padding to fill the available space.
+ swipeRefreshLayout.setPadding(0, 0, 0, 0);
+ } else { // The app bar is at the top.
+ // Check to see if the app bar is normally scrolled.
+ if (scrollAppBar) { // The app bar is scrolled when it is displayed.
+ // Get the swipe refresh layout parameters.
+ CoordinatorLayout.LayoutParams swipeRefreshLayoutParams = (CoordinatorLayout.LayoutParams) swipeRefreshLayout.getLayoutParams();
+
+ // Remove the off-screen scrolling layout.
+ swipeRefreshLayoutParams.setBehavior(null);
+ } else { // The app bar is not scrolled when it is displayed.
+ // Remove the padding from the top of the swipe refresh layout.
+ swipeRefreshLayout.setPadding(0, 0, 0, 0);
+
+ // The swipe refresh circle must be moved above the now removed status bar location.
+ swipeRefreshLayout.setProgressViewOffset(false, -200, defaultProgressViewEndOffset);
+ }
+ }
+ } else { // The app bar is not hidden.
+ // Adjust the UI for the bottom app bar.
+ if (bottomAppBar) {
+ // Adjust the UI according to the scrolling of the app bar.
+ if (scrollAppBar) {
+ // Reset the WebView padding to fill the available space.
+ swipeRefreshLayout.setPadding(0, 0, 0, 0);
+ } else {
+ // Move the WebView above the app bar layout.
+ swipeRefreshLayout.setPadding(0, 0, 0, appBarHeight);
+ }
+ }
+ }
+
+ /* 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 { // Switch to normal viewing mode.
+ // Show the app bar if it was hidden.
+ if (hideAppBar) {
+ // Show the tab linear layout.
+ tabsLinearLayout.setVisibility(View.VISIBLE);
+
+ // Show the action bar.
+ actionBar.show();
+ }
+
+ // Set layout and scrolling parameters according to the position of the app bar.
+ if (bottomAppBar) { // The app bar is at the bottom.
+ // Adjust the UI.
+ if (scrollAppBar) {
+ // Reset the WebView padding to fill the available space.
+ swipeRefreshLayout.setPadding(0, 0, 0, 0);
+ } else {
+ // Move the WebView above the app bar layout.
+ swipeRefreshLayout.setPadding(0, 0, 0, appBarHeight);
+ }
+ } else { // The app bar is at the top.
+ // Check to see if the app bar is normally scrolled.
+ if (scrollAppBar) { // The app bar is scrolled when it is displayed.
+ // Get the swipe refresh layout parameters.
+ CoordinatorLayout.LayoutParams swipeRefreshLayoutParams = (CoordinatorLayout.LayoutParams) swipeRefreshLayout.getLayoutParams();
+
+ // Add the off-screen scrolling layout.
+ swipeRefreshLayoutParams.setBehavior(new AppBarLayout.ScrollingViewBehavior());
+ } else { // The app bar is not scrolled when it is displayed.
+ // The swipe refresh layout must be manually moved below the app bar layout.
+ swipeRefreshLayout.setPadding(0, appBarHeight, 0, 0);
+
+ // The swipe to refresh circle doesn't always hide itself completely unless it is moved up 10 pixels.
+ swipeRefreshLayout.setProgressViewOffset(false, defaultProgressViewStartOffset - 10 + appBarHeight, defaultProgressViewEndOffset + appBarHeight);
+ }
+ }
+
+ // Remove the `SYSTEM_UI` flags from the root frame layout.
+ rootFrameLayout.setSystemUiVisibility(0);
+ }
+
+ // Consume the double-tap.
+ return true;
+ } else { // Do not consume the double-tap because full screen browsing mode is disabled.
+ return false;
+ }
+ }
+
+ @Override
+ public boolean onFling(MotionEvent motionEvent1, MotionEvent motionEvent2, float velocityX, float velocityY) {
+ // Scroll the bottom app bar if enabled.
+ if (bottomAppBar && scrollAppBar && !objectAnimator.isRunning()) {
+ // Calculate the Y change.
+ float motionY = motionEvent2.getY() - motionEvent1.getY();
+
+ // Scroll the app bar if the change is greater than 50 pixels.
+ if (motionY > 50) {
+ // Animate the bottom app bar onto the screen.
+ objectAnimator = ObjectAnimator.ofFloat(appBarLayout, "translationY", 0);
+ } else if (motionY < -50) {
+ // Animate the bottom app bar off the screen.
+ objectAnimator = ObjectAnimator.ofFloat(appBarLayout, "translationY", appBarLayout.getHeight());
+ }
+
+ // Make it so.
+ objectAnimator.start();
+ }
+
+ // Do not consume the event.
+ return false;
+ }
+ });
+
+ // Pass all touch events on the WebView through the double-tap gesture detector.
+ nestedScrollWebView.setOnTouchListener((View view, MotionEvent event) -> {
+ // Call `performClick()` on the view, which is required for accessibility.
+ view.performClick();
+
+ // Send the event to the gesture detector.
+ return doubleTapGestureDetector.onTouchEvent(event);
+ });
+
+ // Register the WebView for a context menu. This is used to see link targets and download images.
+ registerForContextMenu(nestedScrollWebView);
+
+ // Allow the downloading of files.
+ nestedScrollWebView.setDownloadListener((String downloadUrl, String userAgent, String contentDisposition, String mimetype, long contentLength) -> {
+ // Check the download preference.
+ if (downloadWithExternalApp) { // Download with an external app.
+ downloadUrlWithExternalApp(downloadUrl);
+ } else { // Handle the download inside of Privacy Browser.
+ // Define a formatted file size string.
+ String formattedFileSizeString;
+
+ // Process the content length if it contains data.
+ if (contentLength > 0) { // The content length is greater than 0.
+ // Format the content length as a string.
+ formattedFileSizeString = NumberFormat.getInstance().format(contentLength) + " " + getString(R.string.bytes);
+ } else { // The content length is not greater than 0.
+ // Set the formatted file size string to be `unknown size`.
+ formattedFileSizeString = getString(R.string.unknown_size);
+ }
+
+ // Get the file name from the content disposition.
+ String fileNameString = UrlHelper.getFileName(this, contentDisposition, mimetype, downloadUrl);
+
+ // Instantiate the save dialog.
+ DialogFragment saveDialogFragment = SaveDialog.saveUrl(downloadUrl, fileNameString, formattedFileSizeString, userAgent,
+ nestedScrollWebView.getAcceptCookies());
+
+ // Try to show the dialog. The download listener continues to function even when the WebView is paused. Attempting to display a dialog in that state leads to a crash.
+ try {
+ // Show the save dialog. It must be named `save_dialog` so that the file picker can update the file name.
+ saveDialogFragment.show(getSupportFragmentManager(), getString(R.string.save_dialog));
+ } catch (Exception exception) { // The dialog could not be shown.
+ // Add the dialog to the pending dialog array list. It will be displayed in `onStart()`.
+ pendingDialogsArrayList.add(new PendingDialogDataClass(saveDialogFragment, getString(R.string.save_dialog)));
+ }
+ }
+ });
+
+ // Update the find on page count.
+ nestedScrollWebView.setFindListener(new WebView.FindListener() {
+ // Get a handle for `findOnPageCountTextView`.
+ final TextView findOnPageCountTextView = findViewById(R.id.find_on_page_count_textview);
+
+ @Override
+ public void onFindResultReceived(int activeMatchOrdinal, int numberOfMatches, boolean isDoneCounting) {
+ if ((isDoneCounting) && (numberOfMatches == 0)) { // There are no matches.
+ // Set `findOnPageCountTextView` to `0/0`.
+ findOnPageCountTextView.setText(R.string.zero_of_zero);
+ } else if (isDoneCounting) { // There are matches.
+ // `activeMatchOrdinal` is zero-based.
+ int activeMatch = activeMatchOrdinal + 1;
+
+ // Build the match string.
+ String matchString = activeMatch + "/" + numberOfMatches;
+
+ // Set `findOnPageCountTextView`.
+ findOnPageCountTextView.setText(matchString);
+ }
+ }
+ });
+
+ // Process scroll changes.
+ nestedScrollWebView.setOnScrollChangeListener((view, scrollX, scrollY, oldScrollX, oldScrollY) -> {
+ // Set the swipe to refresh status.
+ if (nestedScrollWebView.getSwipeToRefresh()) {
+ // Only enable swipe to refresh if the WebView is scrolled to the top.
+ swipeRefreshLayout.setEnabled(nestedScrollWebView.getScrollY() == 0);
+ } else {
+ // Disable swipe to refresh.
+ swipeRefreshLayout.setEnabled(false);
+ }
+
+ // Reinforce the system UI visibility flags if in full screen browsing mode.
+ // This hides the status and navigation bars, which are displayed if other elements are shown, like dialog boxes, the options menu, or the keyboard.
+ if (inFullScreenBrowsingMode) {
+ /* 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.