How to use accessibility service in Flutter - Platform Specific

Question

I'm trying to integrate accessibility service in the flutter based application and I dug into it and found out that I will have to use method channels in order to achieve this task because it is possible only by using android native code (java/kotlin)

As you know, We must write the code inside MainActivity that extends FlutterActivity in order to make it work. How to extend AccessibilityService in this platform-specific code?

public class MainActivity extends FlutterActivity {
  private static final String CHANNEL = "samples.flutter.dev/battery";

  @Override
  public void configureFlutterEngine(@NonNull FlutterEngine flutterEngine) {
  super.configureFlutterEngine(flutterEngine);
    new MethodChannel(flutterEngine.getDartExecutor().getBinaryMessenger(), CHANNEL)
        .setMethodCallHandler(
          (call, result) -> {
            // Note: this method is invoked on the main thread.
            // TODO
          }
        );
  }
}

This is the code that I'm trying to implement in Flutter and one question, do I need to invoke this code from the Flutter client end? because as far as I know, accessibility service code is automatically called by the android system

public class MyAccessibilityService extends AccessibilityService {
...
    @Override
    public void onAccessibilityEvent(AccessibilityEvent event) {
if (event.getEventType() == AccessibilityEvent.TYPE_NOTIFICATION_STATE_CHANGED) {
    if (event.getPackageName().toString().equals("com.whatsapp")){
        StringBuilder message = new StringBuilder();
        if (!event.getText().isEmpty()) {
            for (CharSequence subText : event.getText()) {
                message.append(subText);
            }
            if (message.toString().contains("Message from")){
                name=message.toString().substring(13);
            }
        }
    }
}
    }

    @Override
    public void onInterrupt() {
    }

...
}

Answer 1

days ago I made a flutter plugin to interact with Accessibility Service in Android. it's easy to use just follow the instruction in the readme and check the example for more details flutter_accessibility_service

this is an example of how to use it

 /// check if accessibility permession is enebaled
 final bool status = await FlutterAccessibilityService.isAccessibilityPermissionEnabled();
 
 /// request accessibility permission
 /// it will open the accessibility settings page
 await FlutterAccessibilityService.requestAccessibilityPermission();
 
 /// stream the incoming Accessibility events
  FlutterAccessibilityService.accessStream.listen((event) {
    log("Current Event: $event");
  
  /*
  Current Event: AccessibilityEvent: (
     Action Type: 0 
     Event Time: 2022-04-11 14:19:56.556834 
     Package Name: com.facebook.katana 
     Event Type: EventType.typeWindowContentChanged 
     Captured Text: events you may like 
     content Change Types: ContentChangeTypes.contentChangeTypeSubtree 
     Movement Granularity: 0
     Is Active: true
     is focused: true
     in Pip: false
     window Type: WindowType.typeApplication
)
  */
  
  });