ExploreByTouchHelper

Virtual node identifier value for invalid nodes.

Factory method to create a new ExploreByTouchHelper.

Dispatches hover MotionEvents to the virtual view hierarchy when the Explore by Touch feature is enabled.

This method should be called by overriding dispatchHoverEvent(MotionEvent):

@Override
 public boolean dispatchHoverEvent(MotionEvent event) {
   if (mHelper.dispatchHoverEvent(this, event) {
     return true;
   }
   return super.dispatchHoverEvent(event);
 }
 

Returns the AccessibilityNodeProviderCompat for this helper.

Returns the virtual view id for the currently focused item,

Notifies the accessibility framework that the properties of the parent view have changed.

You must call this method after adding or removing items from the parent view.

Notifies the accessibility framework that the properties of a particular item have changed.

You must call this method after changing any of the properties set in onPopulateNodeForVirtualView(int, AccessibilityNodeInfoCompat).

Populates an event of the specified type with information about an item and attempts to send it up through the view hierarchy.

You should call this method after performing a user action that normally fires an accessibility event, such as clicking on an item.

public void performItemClick(T item) {
   ...
   sendEventForVirtualViewId(item.id, AccessibilityEvent.TYPE_VIEW_CLICKED);
 }
 

Provides a mapping between view-relative coordinates and logical items.

Populates a list with the view's visible items. The ordering of items within virtualViewIds specifies order of accessibility focus traversal.

Performs the specified accessibility action on the item associated with the virtual view identifier. See performAction(int, Bundle) for more information.

Implementations must handle any actions added manually in onPopulateNodeForVirtualView(int, AccessibilityNodeInfoCompat).

The helper class automatically handles focus management resulting from ACTION_ACCESSIBILITY_FOCUS and ACTION_CLEAR_ACCESSIBILITY_FOCUS actions.

Populates an AccessibilityEvent with information about the specified item.

Implementations must populate the following required fields:

• event text, see getText() or setContentDescription(CharSequence)

The helper class automatically populates the following fields with default values, but implementations may optionally override them:

• item class name, set to android.view.View, see setClassName(CharSequence)

The following required fields are automatically populated by the helper class and may not be overridden:

• package name, set to the package of the host view's Context, see setPackageName(CharSequence)
• event source, set to the host view and virtual view identifier, see setSource(View, int)

Populates an AccessibilityNodeInfoCompat with information about the specified item.

Implementations must populate the following required fields:

• event text, see setText(CharSequence) or setContentDescription(CharSequence)
• bounds in parent coordinates, see setBoundsInParent(Rect)

The helper class automatically populates the following fields with default values, but implementations may optionally override them:

• enabled state, set to true, see setEnabled(boolean)
• item class name, identical to the class name set by onPopulateEventForVirtualView(int, AccessibilityEvent), see setClassName(CharSequence)

The following required fields are automatically populated by the helper class and may not be overridden:

• package name, identical to the package name set by onPopulateEventForVirtualView(int, AccessibilityEvent), see setPackageName(CharSequence)
• node source, identical to the event source set in onPopulateEventForVirtualView(int, AccessibilityEvent), see setSource(View, int)
• parent view, set to the host view, see setParent(View)
• visibility, computed based on parent-relative bounds, see setVisibleToUser(boolean)
• accessibility focus, computed based on internal helper state, see setAccessibilityFocused(boolean)
• bounds in screen coordinates, computed based on host view bounds, see setBoundsInScreen(Rect)

Additionally, the helper class automatically handles accessibility focus management by adding the appropriate ACTION_ACCESSIBILITY_FOCUS or ACTION_CLEAR_ACCESSIBILITY_FOCUS action. Implementations must never manually add these actions.

The helper class also automatically modifies parent- and screen-relative bounds to reflect the portion of the item visible within its parent.