AccessibilityDelegateCompat

public class AccessibilityDelegateCompat
extends Object

java.lang.Object
   ↳ androidx.core.view.AccessibilityDelegateCompat


Helper for accessing View.AccessibilityDelegate.

Note: On platform versions prior to API 23, delegate methods on views in the android.widget.* package are called before host methods. This prevents certain properties such as class name from being modified by overriding onInitializeAccessibilityNodeInfo(View, AccessibilityNodeInfoCompat), as any changes will be overwritten by the host class.

Starting in API 23, delegate methods are called after host methods, which all properties to be modified without being overwritten by the host class.

Summary

Public constructors

AccessibilityDelegateCompat()

Creates a new instance.

Public methods

boolean dispatchPopulateAccessibilityEvent(View host, AccessibilityEvent event)

Dispatches an AccessibilityEvent to the host View first and then to its children for adding their text content to the event.

AccessibilityNodeProviderCompat getAccessibilityNodeProvider(View host)

Gets the provider for managing a virtual view hierarchy rooted at this View and reported to AccessibilityServices that explore the window content.

void onInitializeAccessibilityEvent(View host, AccessibilityEvent event)

Initializes an AccessibilityEvent with information about the the host View which is the event source.

void onInitializeAccessibilityNodeInfo(View host, AccessibilityNodeInfoCompat info)

Initializes an AccessibilityNodeInfoCompat with information about the host view.

void onPopulateAccessibilityEvent(View host, AccessibilityEvent event)

Gives a chance to the host View to populate the accessibility event with its text content.

boolean onRequestSendAccessibilityEvent(ViewGroup host, View child, AccessibilityEvent event)

Called when a child of the host View has requested sending an AccessibilityEvent and gives an opportunity to the parent (the host) to augment the event.

boolean performAccessibilityAction(View host, int action, Bundle args)

Performs the specified accessibility action on the view.

void sendAccessibilityEvent(View host, int eventType)

Sends an accessibility event of the given type.

void sendAccessibilityEventUnchecked(View host, AccessibilityEvent event)

Sends an accessibility event.

Inherited methods

Public constructors

AccessibilityDelegateCompat

public AccessibilityDelegateCompat ()

Creates a new instance.

Public methods

dispatchPopulateAccessibilityEvent

public boolean dispatchPopulateAccessibilityEvent (View host, 
                AccessibilityEvent event)

Dispatches an AccessibilityEvent to the host View first and then to its children for adding their text content to the event.

The default implementation behaves as View#dispatchPopulateAccessibilityEvent(AccessibilityEvent) for the case of no accessibility delegate been set.

Parameters
host View: The View hosting the delegate.

event AccessibilityEvent: The event.

Returns
boolean True if the event population was completed.

getAccessibilityNodeProvider

public AccessibilityNodeProviderCompat getAccessibilityNodeProvider (View host)

Gets the provider for managing a virtual view hierarchy rooted at this View and reported to AccessibilityServices that explore the window content.

The default implementation behaves as ViewCompat#getAccessibilityNodeProvider(View) for the case of no accessibility delegate been set.

Parameters
host View

Returns
AccessibilityNodeProviderCompat The provider.

onInitializeAccessibilityEvent

public void onInitializeAccessibilityEvent (View host, 
                AccessibilityEvent event)

Initializes an AccessibilityEvent with information about the the host View which is the event source.

The default implementation behaves as ViewCompat#onInitalizeAccessibilityEvent(View v, AccessibilityEvent event) for the case of no accessibility delegate been set.

Parameters
host View: The View hosting the delegate.

event AccessibilityEvent: The event to initialize.

onInitializeAccessibilityNodeInfo

public void onInitializeAccessibilityNodeInfo (View host, 
                AccessibilityNodeInfoCompat info)

Initializes an AccessibilityNodeInfoCompat with information about the host view.

The default implementation behaves as ViewCompat#onInitializeAccessibilityNodeInfo(View, AccessibilityNodeInfoCompat) for the case of no accessibility delegate been set.

Parameters
host View: The View hosting the delegate.

info AccessibilityNodeInfoCompat: The instance to initialize.

onPopulateAccessibilityEvent

public void onPopulateAccessibilityEvent (View host, 
                AccessibilityEvent event)

Gives a chance to the host View to populate the accessibility event with its text content.

The default implementation behaves as ViewCompat#onPopulateAccessibilityEvent(AccessibilityEvent) for the case of no accessibility delegate been set.

Parameters
host View: The View hosting the delegate.

event AccessibilityEvent: The accessibility event which to populate.

onRequestSendAccessibilityEvent

public boolean onRequestSendAccessibilityEvent (ViewGroup host, 
                View child, 
                AccessibilityEvent event)

Called when a child of the host View has requested sending an AccessibilityEvent and gives an opportunity to the parent (the host) to augment the event.

The default implementation behaves as ViewGroupCompat#onRequestSendAccessibilityEvent(ViewGroup, View, AccessibilityEvent) for the case of no accessibility delegate been set.

Parameters
host ViewGroup: The View hosting the delegate.

child View: The child which requests sending the event.

event AccessibilityEvent: The event to be sent.

Returns
boolean True if the event should be sent

performAccessibilityAction

public boolean performAccessibilityAction (View host, 
                int action, 
                Bundle args)

Performs the specified accessibility action on the view. For possible accessibility actions look at AccessibilityNodeInfoCompat.

The default implementation behaves as View#performAccessibilityAction(int, Bundle) for the case of no accessibility delegate been set.

Parameters
host View

action int: The action to perform.

args Bundle

Returns
boolean Whether the action was performed.

sendAccessibilityEvent

public void sendAccessibilityEvent (View host, 
                int eventType)

Sends an accessibility event of the given type. If accessibility is not enabled this method has no effect.

The default implementation behaves as View#sendAccessibilityEvent(int) for the case of no accessibility delegate been set.

Parameters
host View: The View hosting the delegate.

eventType int: The type of the event to send.

sendAccessibilityEventUnchecked

public void sendAccessibilityEventUnchecked (View host, 
                AccessibilityEvent event)

Sends an accessibility event. This method behaves exactly as sendAccessibilityEvent(View, int) but takes as an argument an empty AccessibilityEvent and does not perform a check whether accessibility is enabled.

The default implementation behaves as View#sendAccessibilityEventUnchecked(AccessibilityEvent) for the case of no accessibility delegate been set.

Parameters
host View: The View hosting the delegate.

event AccessibilityEvent: The event to send.