|
|||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | ||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
java.lang.Objectandroid.support.v4.view.AccessibilityDelegateCompat
android.support.v4.widget.ExploreByTouchHelper
public abstract class ExploreByTouchHelper
ExploreByTouchHelper is a utility class for implementing accessibility
support in custom View
s that represent a collection of View-like
logical items. It extends AccessibilityNodeProviderCompat
and
simplifies many aspects of providing information to accessibility services
and managing accessibility focus. This class does not currently support
hierarchies of logical items.
This should be applied to the parent view using
ViewCompat.setAccessibilityDelegate(android.view.View, android.support.v4.view.AccessibilityDelegateCompat)
:
mAccessHelper = ExploreByTouchHelper.create(someView, mAccessHelperCallback); ViewCompat.setAccessibilityDelegate(someView, mAccessHelper);
Field Summary | |
---|---|
static int |
INVALID_ID
Virtual node identifier value for invalid nodes. |
Constructor Summary | |
---|---|
ExploreByTouchHelper(android.view.View forView)
Factory method to create a new ExploreByTouchHelper . |
Method Summary | |
---|---|
boolean |
dispatchHoverEvent(android.view.MotionEvent event)
Dispatches hover MotionEvent s to the virtual view hierarchy when
the Explore by Touch feature is enabled. |
AccessibilityNodeProviderCompat |
getAccessibilityNodeProvider(android.view.View host)
Returns the AccessibilityNodeProviderCompat for this helper. |
int |
getFocusedVirtualView()
Returns the virtual view id for the currently focused item, |
protected abstract int |
getVirtualViewAt(float x,
float y)
Provides a mapping between view-relative coordinates and logical items. |
protected abstract void |
getVisibleVirtualViews(java.util.List<java.lang.Integer> virtualViewIds)
Populates a list with the view's visible items. |
void |
invalidateRoot()
Notifies the accessibility framework that the properties of the parent view have changed. |
void |
invalidateVirtualView(int virtualViewId)
Notifies the accessibility framework that the properties of a particular item have changed. |
protected abstract boolean |
onPerformActionForVirtualView(int virtualViewId,
int action,
android.os.Bundle arguments)
Performs the specified accessibility action on the item associated with the virtual view identifier. |
protected abstract void |
onPopulateEventForVirtualView(int virtualViewId,
android.view.accessibility.AccessibilityEvent event)
Populates an AccessibilityEvent with information about the
specified item. |
protected abstract void |
onPopulateNodeForVirtualView(int virtualViewId,
AccessibilityNodeInfoCompat node)
Populates an AccessibilityNodeInfoCompat with information
about the specified item. |
boolean |
sendEventForVirtualView(int virtualViewId,
int eventType)
Populates an event of the specified type with information about an item and attempts to send it up through the view hierarchy. |
Methods inherited from class android.support.v4.view.AccessibilityDelegateCompat |
---|
dispatchPopulateAccessibilityEvent, onInitializeAccessibilityEvent, onInitializeAccessibilityNodeInfo, onPopulateAccessibilityEvent, onRequestSendAccessibilityEvent, performAccessibilityAction, sendAccessibilityEvent, sendAccessibilityEventUnchecked |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
---|
public static final int INVALID_ID
Constructor Detail |
---|
public ExploreByTouchHelper(android.view.View forView)
ExploreByTouchHelper
.
forView
- View whose logical children are exposed by this helper.Method Detail |
---|
public AccessibilityNodeProviderCompat getAccessibilityNodeProvider(android.view.View host)
AccessibilityNodeProviderCompat
for this helper.
getAccessibilityNodeProvider
in class AccessibilityDelegateCompat
host
- View whose logical children are exposed by this helper.
AccessibilityNodeProviderCompat
public boolean dispatchHoverEvent(android.view.MotionEvent event)
MotionEvent
s to the virtual view hierarchy when
the Explore by Touch feature is enabled.
This method should be called by overriding
View#dispatchHoverEvent
:
@Override public boolean dispatchHoverEvent(MotionEvent event) { if (mHelper.dispatchHoverEvent(this, event) { return true; } return super.dispatchHoverEvent(event); }
event
- The hover event to dispatch to the virtual view hierarchy.
public boolean sendEventForVirtualView(int virtualViewId, int eventType)
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); }
virtualViewId
- The virtual view id for which to send an event.eventType
- The type of event to send.
public void invalidateRoot()
You must call this method after adding or removing items from the parent view.
public void invalidateVirtualView(int virtualViewId)
You must call this method after changing any of the properties set
in onPopulateNodeForVirtualView(int, android.support.v4.view.accessibility.AccessibilityNodeInfoCompat)
.
virtualViewId
- The virtual view id to invalidate.public int getFocusedVirtualView()
INVALID_ID
if no item is
currently focused.protected abstract int getVirtualViewAt(float x, float y)
x
- The view-relative x coordinatey
- The view-relative y coordinate
protected abstract void getVisibleVirtualViews(java.util.List<java.lang.Integer> virtualViewIds)
virtualViewIds
specifies order of accessibility focus
traversal.
virtualViewIds
- The list to populate with visible itemsprotected abstract void onPopulateEventForVirtualView(int virtualViewId, android.view.accessibility.AccessibilityEvent event)
AccessibilityEvent
with information about the
specified item.
Implementations must populate the following required fields:
AccessibilityEvent.getText()
or
AccessibilityEvent.setContentDescription(java.lang.CharSequence)
The helper class automatically populates the following fields with default values, but implementations may optionally override them:
AccessibilityEvent.setClassName(java.lang.CharSequence)
The following required fields are automatically populated by the helper class and may not be overridden:
Context
, see AccessibilityEvent.setPackageName(java.lang.CharSequence)
AccessibilityRecordCompat.setSource(View, int)
virtualViewId
- The virtual view id for the item for which to
populate the eventevent
- The event to populateprotected abstract void onPopulateNodeForVirtualView(int virtualViewId, AccessibilityNodeInfoCompat node)
AccessibilityNodeInfoCompat
with information
about the specified item.
Implementations must populate the following required fields:
AccessibilityNodeInfoCompat.setText(java.lang.CharSequence)
or
AccessibilityNodeInfoCompat.setContentDescription(java.lang.CharSequence)
AccessibilityNodeInfoCompat.setBoundsInParent(android.graphics.Rect)
The helper class automatically populates the following fields with default values, but implementations may optionally override them:
AccessibilityNodeInfoCompat.setEnabled(boolean)
onPopulateEventForVirtualView(int, android.view.accessibility.AccessibilityEvent)
, see
AccessibilityNodeInfoCompat.setClassName(java.lang.CharSequence)
The following required fields are automatically populated by the helper class and may not be overridden:
onPopulateEventForVirtualView(int, android.view.accessibility.AccessibilityEvent)
, see
AccessibilityNodeInfoCompat.setPackageName(java.lang.CharSequence)
onPopulateEventForVirtualView(int, android.view.accessibility.AccessibilityEvent)
, see
AccessibilityNodeInfoCompat.setSource(View, int)
AccessibilityNodeInfoCompat.setParent(View)
AccessibilityNodeInfoCompat.setVisibleToUser(boolean)
AccessibilityNodeInfoCompat.setAccessibilityFocused(boolean)
AccessibilityNodeInfoCompat.setBoundsInScreen(android.graphics.Rect)
Additionally, the helper class automatically handles accessibility
focus management by adding the appropriate
AccessibilityNodeInfoCompat.ACTION_ACCESSIBILITY_FOCUS
or
AccessibilityNodeInfoCompat.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.
virtualViewId
- The virtual view identifier of the item for
which to populate the nodenode
- The node to populateprotected abstract boolean onPerformActionForVirtualView(int virtualViewId, int action, android.os.Bundle arguments)
AccessibilityNodeInfoCompat.performAction(int, Bundle)
for
more information.
Implementations must handle any actions added manually in
onPopulateNodeForVirtualView(int, android.support.v4.view.accessibility.AccessibilityNodeInfoCompat)
.
The helper class automatically handles focus management resulting
from AccessibilityNodeInfoCompat.ACTION_ACCESSIBILITY_FOCUS
and
AccessibilityNodeInfoCompat.ACTION_CLEAR_ACCESSIBILITY_FOCUS
actions.
virtualViewId
- The virtual view identifier of the item on which
to perform the actionaction
- The accessibility action to performarguments
- (Optional) A bundle with additional arguments, or
null
|
|||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | ||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |