The document explains how to use the accessibility API in Android to develop services that enhance app accessibility, particularly for users with disabilities. It details the steps to create an accessibility service, including defining it in the manifest and configuring it using an XML file. Additional information is provided on handling accessibility events, querying the view hierarchy, and performing actions on UI elements within the service.

1. Використання Accessibility API для
доступу до View/Window інших додатків.
Застосування API в розробці додатків
для людей з обмеженими здібностями або
додатків для автоматизації
користувальницьких дій/UX

35. Create Your Accessibility
Service
An accessibility service can be bundled with a normal application, or created as a standalone Android project.
The steps to creating the service are the same in either situation. Within your project, create a class that
extends AccessibilityService.
package com.example.android.apis.accessibility;
import android.accessibilityservice.AccessibilityService;
public class MyAccessibilityService extends AccessibilityService {
…
@Override
public void onAccessibilityEvent(AccessibilityEvent event) {
}
@Override
public void onInterrupt() {
}
…
}

36. Like any other service, you also declare it in the manifest file. Remember
to specify that it handles the android.accessibilityservice intent, so that
the service is called when applications fire an AccessibilityEvent.
<application …>
…
<service android:name=”.MyAccessibilityService”>
<intent-filter>
<action android:name=”android.accessibilityservice.AccessibilityService” />
</intent-filter>
. . .
</service>
…
</application>

37. Accessibility need enable
manually!!!

38. Configure Your Accessibility Service
@Override
public void onServiceConnected() {
// Set the type of events that this service wants to listen to. Others
// won’t be passed to this service.
info.eventTypes = AccessibilityEvent.TYPE_VIEW_CLICKED |
AccessibilityEvent.TYPE_VIEW_FOCUSED;
// If you only want this service to work with specific applications, set their
// package names here. Otherwise, when the service is activated, it will listen
// to events from all applications.
info.packageNames = new String[]
{“com.example.android.myFirstApp”, “com.example.android.mySecondApp”};
// Set the type of feedback your service will provide.
info.feedbackType = AccessibilityServiceInfo.FEEDBACK_SPOKEN;
// Default services are invoked only if no package-specific ones are present
// for the type of AccessibilityEvent generated. This service *is*
// application-specific, so the flag isn’t necessary. If this was a
// general-purpose service, it would be worth considering setting the
// DEFAULT flag.
// info.flags = AccessibilityServiceInfo.DEFAULT;
info.notificationTimeout = 100;
this.setServiceInfo(info);
}

39. Starting with Android 4.0, there is a second option available: configure the service using
an XML file. Certain configuration options like canRetrieveWindowContent are only
available if you configure your service using XML. The same configuration options above,
defined using XML, would look like this:
<accessibility-service
android:accessibilityEventTypes=”typeViewClicked|typeViewFocused”
android:packageNames=”com.example.android.myFirstApp, com.example.android.mySecondApp”
android:accessibilityFeedbackType=”feedbackSpoken”
android:notificationTimeout=”100″
android:settingsActivity=”com.example.android.apis.accessibility.TestBackActivity”
android:canRetrieveWindowContent=”true”
/>
If you go the XML route, be sure to reference it in your manifest, by adding a <meta-data>
tag to your service declaration, pointing at the XML file. If you stored your XML file in
res/xml/serviceconfig.xml, the new tag would look like this:
<service android:name=”.MyAccessibilityService”>
<intent-filter>
<action android:name=”android.accessibilityservice.AccessibilityService” />
</intent-filter>
<meta-data android:name=”android.accessibilityservice”
android:resource=”@xml/serviceconfig” />
</service>

40. Respond to AccessibilityEvents
Now that your service is set up to run and listen for events, write some code so it knows what to do
when an AccessibilityEvent actually arrives! Start by overriding the
onAccessibilityEvent(AccessibilityEvent) method. In that method, use getEventType() to determine
the type of event, and getContentDescription() to extract any label text associated with the fiew that
fired the event.
@Override
public void onAccessibilityEvent(AccessibilityEvent event) {
final int eventType = event.getEventType();
String eventText = null;
switch(eventType) {
case AccessibilityEvent.TYPE_VIEW_CLICKED:
eventText = “Focused: “;
break;
case AccessibilityEvent.TYPE_VIEW_FOCUSED:
eventText = “Focused: “;
break;
}
eventText = eventText + event.getContentDescription();
}

41. Advanced service to access the
window hierarchy

42. Query the View Heirarchy for More Context
This step is optional, but highly useful. One of the new features in Android 4.0 (API Level
14) is the ability for an AccessibilityService to query the view hierarchy, collecting
information about the the UI component that generated an event, and its parent and
children. In order to do this, make sure that you set the following line in your XML
configuration:
android:canRetrieveWindowContent=”true”
Once that’s done, get an AccessibilityNodeInfo object using getSource(). This call only
returns an object if the window where the event originated is still the active window. If not,
it will return null, so behave accordingly. The following example is a snippet of code that,
when it receives an event, does the following:
1. Immediately grab the parent of the view where the event originated
2. In that view, look for a label and a check box as children views
3. If it finds them, create a string to report to the user, indicating the label and whether it
was checked or not.
4. If at any point a null value is returned while traversing the view hierarchy, the method
quietly gives up.

43. // Alternative onAccessibilityEvent, that uses AccessibilityNodeInfo
@Override
public void onAccessibilityEvent(AccessibilityEvent event) {
AccessibilityNodeInfo source = event.getSource();
if (source == null) {
return;
}
CharSequence taskLabel = source.getText();
final boolean isComplete = source.isChecked();
}

44. Grab window hierarchy
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
currentNode = event.getSource();
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN)
rootNode = getRootInActiveWindow();//Node from root window
}
And then....

45. Get list of View's in current window
...
scanNode(rootNode, EditText.class.getName());
...
private void scanNode(final AccessibilityNodeInfo node, final String mask) {
try{
if (node == null)
return;
for (int i = 0; i < node.getChildCount(); i++) {
final AccessibilityNodeInfo tmpnode = node.getChild(i);
if (tmpnode == null)
break;
if (tmpnode.getChildCount() > 0)
scanNode(tmpnode, mask);
else if (tmpnode.getClassName().equals(mask)) {
eventList.add(tmpnode);
}
}}
catch (Exception ex){
ex.printStackTrace();
}
}

46. Perform actions in View
for (AccessibilityNodeInfo info : editsList) {
info.performAction(AccessibilityNodeInfo.ACTION_FOCUS);
info.performAction(AccessibilityNodeInfo.ACTION_LONG_CLICK);
SetTextToClipboard(''Hello MMDAY Lviv);
info.performAction(AccessibilityNodeInfo.ACTION_PASTE);
}

47. Advanced Accessibility Service
in action

48. Sergey Komlach
Lamantine Software a.s
2014
sergey.komlach@stickypassword.com