handlermessage-snippet

handlermessage-snippet.java

public class ReceiveFromServiceActivity extends AppCompatActivity {

    // Message handler of the service
    class ResponseHandler extends Handler {
        @Override public void handleMessage(Message message) {
            Toast.makeText(ReceiveFromServiceActivity.this, "message from service : " + message.getData().getString("message"),
                    Toast.LENGTH_SHORT).show();
        }
    }
    // Messenger toward the activity
    Messenger messenger = new Messenger(new ResponseHandler());

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        ...
        Intent intent = new Intent(this, SendingService.class);
        // Passing of the messenger to the service
        intent.putExtra("activityMessenger", messenger);
        startService(intent);
    }

}

public class SendingService extends Service {

    // Messenger toward the activity
    private Messenger activityMessenger;

    @Override
    public void onStart(Intent intent, int startId) {
        // Retrieving of the messenger toward the activity
        activityMessenger = intent.getParcelableExtra("activityMessenger");
        // Send of a message to the activity
        Message messageToActivity = Message.obtain();
        messageToActivity.getData().putString("message", "Hello activity !");
        try {
            activityMessenger.send(messageToActivity);
        } catch (RemoteException e) {
            e.printStackTrace();
        }
    }
}