AccessibilityRequestPreparer
public
abstract
class
AccessibilityRequestPreparer
extends Object
java.lang.Object | |
↳ | android.view.accessibility.AccessibilityRequestPreparer |
Object responsible to ensuring that a View
is prepared to meet a synchronous request for
accessibility data.
Because accessibility requests arrive to View
s synchronously on the UI thread, a View
that requires information from other processes can struggle to meet those requests. Registering
an instance of this class with AccessibilityManager
allows a View to be notified when
a request is about to be made, and to asynchronously inform the accessibility system when it is
ready to meet the request.
Note: This class should only be needed in exceptional situations where a
View
cannot otherwise synchronously meet the request for accessibility data.
Summary
Constants | |
---|---|
int |
REQUEST_TYPE_EXTRA_DATA
|
Public constructors | |
---|---|
AccessibilityRequestPreparer(View view, int requestTypes)
|
Public methods | |
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View
|
getView()
Get the view this object was created with. |
abstract
void
|
onPrepareExtraData(int virtualViewId, String extraDataKey, Bundle args, Message preparationFinishedMessage)
Callback to allow preparation for filling extra data. |
Inherited methods | |
---|---|
Constants
REQUEST_TYPE_EXTRA_DATA
public static final int REQUEST_TYPE_EXTRA_DATA
Constant Value: 1 (0x00000001)
Public constructors
AccessibilityRequestPreparer
public AccessibilityRequestPreparer (View view, int requestTypes)
Parameters | |
---|---|
view |
View : The view whose requests need preparation. It must be attached to a
window. This object will retain a weak reference to this view, and will unregister itself
from AccessibilityManager if the view is detached from a window. It will not re-register
itself. |
requestTypes |
int : The types of requests that require preparation. Different types may
be ORed together.
Value is either 0 or REQUEST_TYPE_EXTRA_DATA |
Throws | |
---|---|
IllegalStateException |
if the view is not attached to a window. |
Public methods
getView
public View getView ()
Get the view this object was created with.
Returns | |
---|---|
View |
The view this object was created with, or null if the weak reference held
to the view is no longer valid. |
onPrepareExtraData
public abstract void onPrepareExtraData (int virtualViewId, String extraDataKey, Bundle args, Message preparationFinishedMessage)
Callback to allow preparation for filling extra data. Only called back if REQUEST_TYPE_EXTRA_DATA is requested.
Parameters | |
---|---|
virtualViewId |
int : The ID of a virtual child node, if the View for this preparer
supports virtual descendents, or AccessibilityNodeProvider#HOST_VIEW_ID
if the request is for the view itself. |
extraDataKey |
String : The extra data key for the request |
args |
Bundle : The arguments for the request |
preparationFinishedMessage |
Message : A message that must be sent to its target when preparations
are complete. |
See also: