android - How to start AccessibilityService?

Question

I'm trying to start my implementation of AccessibilityService by using

Intent mailAccessabilityIntent = new Intent(this, EmailAccessabilityService.class);
startService(mailAccessabilityIntent);

My problem is onServiceConnected() never been called. How do i start this service properly?

Answer 1

Because accessibility services are able to explore and interact with on-screen content, a user has to explicitly enable services in Settings > Accessibility. Once a service is enabled, the system will start it automatically and bind it to the accessibility APIs.

Make sure you declare your service in your application manifest:

<service android:name=".MyAccessibilityService"
         android:permission="android.permission.BIND_ACCESSIBILITY_SERVICE">
     <intent-filter>
         <action android:name="android.accessibilityservice.AccessibilityService" />
     </intent-filter>
     . . .
 </service>

You'll also need to provide configuration for your service, either by overriding setServiceInfo(AccessibilityServiceInfo) or adding a meta-data attribute and XML config file.

The meta-data attribute goes in your <service> declaration after the <intent-filter> tag and looks like this:

<meta-data android:name="android.accessibilityservice"
           android:resource="@xml/accessibilityservice" />

The XML config that you're referencing (in this case, accessibilityservice.xml) looks like this:

<accessibility-service
    android:accessibilityEventTypes="typeViewClicked|typeViewFocused"
    android:packageNames="foo.bar, foo.baz"
    android:accessibilityFeedbackType="feedbackSpoken"
    android:notificationTimeout="100"
    android:accessibilityFlags="flagDefault"
    android:settingsActivity="foo.bar.TestBackActivity"
    android:canRetrieveWindowContent="true"
    . . .
/>

There's more information on which tags you can use at http://developer.android.com/reference/android/R.styleable.html#AccessibilityService