public abstract class AccessibilityNodeProvider extends Object
AccessibilityService explores the window content.
Since the virtual View tree does not exist this class is responsible for
managing the AccessibilityNodeInfos describing that tree to accessibility
services.
The main use case of these APIs is to enable a custom view that draws complex content, for example a monthly calendar grid, to be presented as a tree of logical nodes, for example month days each containing events, thus conveying its logical structure.
A typical use case is to override View.getAccessibilityNodeProvider() of the
View that is a root of a virtual View hierarchy to return an instance of this class.
In such a case this instance is responsible for managing AccessibilityNodeInfos
describing the virtual sub-tree rooted at the View including the one representing the
View itself. Similarly the returned instance is responsible for performing accessibility
actions on any virtual view or the root view itself. For example:
getAccessibilityNodeProvider(
if (mAccessibilityNodeProvider == null) {
mAccessibilityNodeProvider = new AccessibilityNodeProvider() {
public boolean performAction(int action, int virtualDescendantId) {
// Implementation.
return false;
}
public List findAccessibilityNodeInfosByText(String text,
int virtualDescendantId) {
// Implementation.
return null;
}
public AccessibilityNodeInfo createAccessibilityNodeInfo(int virtualDescendantId) {
// Implementation.
return null;
}
});
return mAccessibilityNodeProvider;
| Constructor and Description |
|---|
AccessibilityNodeProvider() |
| Modifier and Type | Method and Description |
|---|---|
AccessibilityNodeInfo |
createAccessibilityNodeInfo(int virtualViewId)
Returns an
AccessibilityNodeInfo representing a virtual view,
i.e. |
List<AccessibilityNodeInfo> |
findAccessibilityNodeInfosByText(String text,
int virtualViewId)
Finds
AccessibilityNodeInfos by text. |
boolean |
performAction(int virtualViewId,
int action,
Bundle arguments)
Performs an accessibility action on a virtual view, i.e.
|
public AccessibilityNodeInfo createAccessibilityNodeInfo(int virtualViewId)
AccessibilityNodeInfo representing a virtual view,
i.e. a descendant of the host View, with the given virtualViewId
or the host View itself if virtualViewId equals to View.NO_ID.
A virtual descendant is an imaginary View that is reported as a part of the view hierarchy for accessibility purposes. This enables custom views that draw complex content to report them selves as a tree of virtual views, thus conveying their logical structure.
The implementer is responsible for obtaining an accessibility node info from the pool of reusable instances and setting the desired properties of the node info before returning it.
virtualViewId - A client defined virtual view id.AccessibilityNodeInfo for a virtual descendant or the
host View.View.createAccessibilityNodeInfo(),
AccessibilityNodeInfopublic boolean performAction(int virtualViewId,
int action,
Bundle arguments)
virtualViewId or the host View itself
if virtualViewId equals to View.NO_ID.virtualViewId - A client defined virtual view id.action - The action to perform.arguments - Optional action arguments.View.performAccessibilityAction(int, Bundle),
createAccessibilityNodeInfo(int),
AccessibilityNodeInfopublic List<AccessibilityNodeInfo> findAccessibilityNodeInfosByText(String text, int virtualViewId)
AccessibilityNodeInfos by text. The match is case insensitive
containment. The search is relative to the virtual view, i.e. a descendant of the
host View, with the given virtualViewId or the host View itself
virtualViewId equals to View.NO_ID.virtualViewId - A client defined virtual view id which defined
the root of the tree in which to perform the search.text - The searched text.createAccessibilityNodeInfo(int),
AccessibilityNodeInfo