1<html> 2<body> 3<p> 4 The classes in this package are used to represent screen content and changes to it 5 as well as APIs for querying the global accessibility state of the system. 6</p> 7<p> 8 {@link android.view.accessibility.AccessibilityEvent}s are sent by the system when 9 something notable happens in the user interface. For example, when a 10 {@link android.widget.Button} is clicked, a {@link android.view.View} is focused, etc. 11</p> 12<p> 13 {@link android.view.accessibility.AccessibilityRecord} contains information 14 about state change of its source {@link android.view.View}. When a view fires 15 an accessibility event it requests from its parent to dispatch the 16 constructed event. The parent may optionally append a record for itself for 17 providing more context to {@link android.accessibilityservice.AccessibilityService}s. 18 Hence, accessibility services can facilitate additional accessibility records 19 to enhance feedback. 20</p> 21<p> 22 {@link android.view.accessibility.AccessibilityNodeInfo} represents a node of the 23 window content as well as actions that can be requested from its source. From the point 24 of view of an {@link android.accessibilityservice.AccessibilityService} a window content is 25 presented as tree of accessibility node info which may or may not map one-to-one 26 to the view hierarchy. In other words, a custom view is free to report itself as 27 a tree of accessibility node info. 28</p> 29<p> 30 {@link android.view.accessibility.AccessibilityManager} is a system level service that 31 serves as an event dispatch for {@link android.view.accessibility.AccessibilityEvent}s, 32 and provides facilities for querying the accessibility state of the system. Accessibility 33 events are generated when something notable happens in the user interface, for example an 34 {@link android.app.Activity} starts, the focus or selection of a {@link android.view.View} 35 changes etc. Parties interested in handling accessibility events implement and register an 36 accessibility service which extends {@link android.accessibilityservice.AccessibilityService}. 37</p> 38<div class="special reference"> 39<h3>Developer Guides</h3> 40<p>For more information about making applications accessible, read the 41<a href="{@docRoot}guide/topics/ui/accessibility/index.html">Accessibility</a> 42developer guide.</p> 43</div> 44 45</body> 46</html> 47