Question

I have an activity thats already binded to the service.
When I start the activity, it binds to the service and gets a value from a variable inside the service. So I can display the value in my activity.

Now I want to read the value of the variable in the service permanently. Not only once while onCreate of my activity is called.
How can I do this?
Whats the right way for this?

Answer 1

There are several ways to accomplish that. One relatively easy way is to use a Handler that triggers itself periodically

public class MyActivity extends Activity {

    private static final int UPDATE_RATE_IN_MS = 500;
    private static final int MSG_UPDATE = 0;

    private Handler mHandler;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mHandler = new Handler() {
            @Override
            public void handleMessage(Message msg) {
                doUpdate();
                mHandler.sendEmptyMessageDelayed(MSG_UPDATE, UPDATE_RATE_IN_MS);
            }
        };
    }

    @Override
    protected void onStart() {
        super.onStart();
        mHandler.sendEmptyMessageDelayed(MSG_UPDATE, UPDATE_RATE_IN_MS);
    }

    @Override
    protected void onStop() {
        super.onStop();
        mHandler.removeMessages(MSG_UPDATE);
    }

    private void doUpdate() {
        // do whatever you need here.
    }
}

You would put the update of the value in doUpdate() in this example.