io.flutter.view.AccessibilityBridge Class Reference

Inheritance diagram for io.flutter.view.AccessibilityBridge:

Public Member Functions
int	getHoveredObjectId ()
boolean	getAccessibleNavigation ()
	AccessibilityBridge ( @NonNull View rootAccessibilityView, @NonNull AccessibilityChannel accessibilityChannel, @NonNull AccessibilityManager accessibilityManager, @NonNull ContentResolver contentResolver, @NonNull PlatformViewsAccessibilityDelegate platformViewsAccessibilityDelegate)
	AccessibilityBridge ( @NonNull View rootAccessibilityView, @NonNull AccessibilityChannel accessibilityChannel, @NonNull AccessibilityManager accessibilityManager, @NonNull ContentResolver contentResolver, @NonNull AccessibilityViewEmbedder accessibilityViewEmbedder, @NonNull PlatformViewsAccessibilityDelegate platformViewsAccessibilityDelegate)

Detailed Description

Bridge between Android's OS accessibility system and Flutter's accessibility system.

An AccessibilityBridge requires:

• A real Android View, called the rootAccessibilityView, which contains a Flutter UI. The rootAccessibilityView is required at the time of
AccessibilityBridge's instantiation and is held for the duration of
AccessibilityBridge's lifespan. AccessibilityBridge invokes various accessibility methods on the rootAccessibilityView, e.g., View#onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo). The rootAccessibilityView is expected to notify the AccessibilityBridge of relevant interactions: onAccessibilityHoverEvent(MotionEvent), reset(), updateSemantics(ByteBuffer, String[], ByteBuffer[]), and updateCustomAccessibilityActions(ByteBuffer, String[])
• An AccessibilityChannel that is connected to the running Flutter app.
• Android's AccessibilityManager to query and listen for accessibility settings.
• Android's ContentResolver to listen for changes to system animation settings.

The AccessibilityBridge causes Android to treat Flutter SemanticsNodes as if they were accessible Android Views. Accessibility requests may be sent from a Flutter widget to the Android OS, as if it were an Android View, and accessibility events may be consumed by a Flutter widget, as if it were an Android View. AccessibilityBridge refers to Flutter's accessible widgets as "virtual views" and identifies them with "virtual view IDs".

Definition at line 80 of file AccessibilityBridge.java.

Constructor & Destructor Documentation

AccessibilityBridge() [1/2]

io.flutter.view.AccessibilityBridge.AccessibilityBridge ( @NonNull View  rootAccessibilityView, @NonNull AccessibilityChannel  accessibilityChannel, @NonNull AccessibilityManager  accessibilityManager, @NonNull ContentResolver  contentResolver, @NonNull PlatformViewsAccessibilityDelegate  platformViewsAccessibilityDelegate  )

inline

Definition at line 416 of file AccessibilityBridge.java.

                                                                                      {
    this(
        rootAccessibilityView,
        accessibilityChannel,
        accessibilityManager,
        contentResolver,
        new AccessibilityViewEmbedder(rootAccessibilityView, MIN_ENGINE_GENERATED_NODE_ID),
        platformViewsAccessibilityDelegate);
  }

AccessibilityBridge() [2/2]

io.flutter.view.AccessibilityBridge.AccessibilityBridge ( @NonNull View  rootAccessibilityView, @NonNull AccessibilityChannel  accessibilityChannel, @NonNull AccessibilityManager  accessibilityManager, @NonNull ContentResolver  contentResolver, @NonNull AccessibilityViewEmbedder  accessibilityViewEmbedder, @NonNull PlatformViewsAccessibilityDelegate  platformViewsAccessibilityDelegate  )

inline

Definition at line 432 of file AccessibilityBridge.java.

                                                                                      {
    this.rootAccessibilityView = rootAccessibilityView;
    this.accessibilityChannel = accessibilityChannel;
    this.accessibilityManager = accessibilityManager;
    this.contentResolver = contentResolver;
    this.accessibilityViewEmbedder = accessibilityViewEmbedder;
    this.platformViewsAccessibilityDelegate = platformViewsAccessibilityDelegate;
    // Tell Flutter whether accessibility is initially active or not. Then register a listener
    // to be notified of changes in the future.
    accessibilityStateChangeListener.onAccessibilityStateChanged(accessibilityManager.isEnabled());
    this.accessibilityManager.addAccessibilityStateChangeListener(accessibilityStateChangeListener);
 
    // Tell Flutter whether touch exploration is initially active or not. Then register a listener
    // to be notified of changes in the future.
    touchExplorationStateChangeListener =
        new AccessibilityManager.TouchExplorationStateChangeListener() {
          @Override
          public void onTouchExplorationStateChanged(boolean isTouchExplorationEnabled) {
            if (isReleased) {
              return;
            }
            if (!isTouchExplorationEnabled) {
              setAccessibleNavigation(false);
              onTouchExplorationExit();
            }
 
            if (onAccessibilityChangeListener != null) {
              onAccessibilityChangeListener.onAccessibilityChanged(
                  accessibilityManager.isEnabled(), isTouchExplorationEnabled);
            }
          }
        };
    touchExplorationStateChangeListener.onTouchExplorationStateChanged(
        accessibilityManager.isTouchExplorationEnabled());
    this.accessibilityManager.addTouchExplorationStateChangeListener(
        touchExplorationStateChangeListener);
 
    // Tell Flutter whether animations should initially be enabled or disabled. Then register a
    // listener to be notified of changes in the future.
    animationScaleObserver.onChange(false);
    Uri transitionUri = Settings.Global.getUriFor(Settings.Global.TRANSITION_ANIMATION_SCALE);
    this.contentResolver.registerContentObserver(transitionUri, false, animationScaleObserver);
 
    // Tells Flutter whether the text should be bolded or not. If the user changes bold text
    // setting, the configuration will change and trigger a re-build of the accesibiltyBridge.
    if (Build.VERSION.SDK_INT >= API_LEVELS.API_31) {
      setBoldTextFlag();
    }
 
    platformViewsAccessibilityDelegate.attachAccessibilityBridge(this);
  }

Member Function Documentation

getAccessibleNavigation()

boolean io.flutter.view.AccessibilityBridge.getAccessibleNavigation ( )

inline

Definition at line 271 of file AccessibilityBridge.java.

                                           {
    return accessibleNavigation;
  }

getHoveredObjectId()

int io.flutter.view.AccessibilityBridge.getHoveredObjectId ( )

inline

Definition at line 245 of file AccessibilityBridge.java.

                                  {
    return hoveredObject.id;
  }

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The documentation for this class was generated from the following file:

• shell/platform/android/io/flutter/view/AccessibilityBridge.java