Question

I have a such Service:

public MyService extends Service {

    // ...

    IBinder binder = new MyBinder();

    @Override
    public IBinder onBind(Intent intent) {
        return binder;
    }

    public class MyBinder extends Binder {

        public MyService getService() {
            return MyService.this;
        }
    }

    // ...
}   

In Activity I receive Binder thereby get Service instance, and after that I have access to all its methods. I want to know, is it safe to do like that? Or I should interact with Service only through Binder interface? Thank you!

Answer 1

In Activity I receive Binder thereby get Service instance, and after
that I have access to all its methods. I want to know, is it safe to
do like that? Or I should interact with Service only through Binder
interface?

The Binder is what gets returned and you simply cast to the Service class you know it to be. The way that you’re doing it IS only using the Binder…

And the way you’ve done it is typically how it’s done. It’s the “local service” pattern taken directly from the “official” sample found here: http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/app/LocalService.html Other ways of calling methods on your Service class are quite hacky (believe me, I’ve tried them before).

Example:

private ServiceConnection mConnection = new ServiceConnection() {
        public void onServiceConnected(ComponentName className, IBinder service) {
            // This is called when the connection with the service has been
            // established, giving us the service object we can use to
            // interact with the service.  Because we have bound to a explicit
            // service that we know is running in our own process, we can
            // cast its IBinder to a concrete class and directly access it.
            myService = ((MyService.LocalBinder)service).getService();



        }

        public void onServiceDisconnected(ComponentName className) {
            // This is called when the connection with the service has been
            // unexpectedly disconnected -- that is, its process crashed.
            // Because it is running in our same process, we should never
            // see this happen.

        }
    };