Android™ Application Development - Bahar Ali Khan

Chapter 8: Working in the Background
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}
@Override
public void onPause() {
earthquakeCursor.deactivate();
super.onPause();
}
public class EarthquakeReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
earthquakeCursor.requery();
MapView earthquakeMap = (MapView)findViewById(R.id.map_view);
earthquakeMap.invalidate();
}
}
Now when the Earthquake Activity is launched, it will start the Earthquake Service. This Service will
then continue to run, updating the earthquake Content Provider in the background, even after the
Activity is suspended or closed.
You’ll continue to upgrade and enhance the Earthquake Service throughout the chapter, fi rst using
Toasts and later Notifi cations.
At this stage, the earthquake processing is done in a Service, but it’s still being executed on the main thread.
Later in this chapter, you’ll learn how to move time-consuming operations onto background threads to
improve performance and avoid “Application Unresponsive” messages.
Binding Activities to Services
When an Activity is bound to a Service, it maintains a reference to the Service instance itself, allowing
you to make method calls on the running Service as you would any other instantiated class.
Binding is available for Activities that would benefi t from a more detailed interface with a Service. To
support binding for a Service, implement the onBind method as shown in the simple example below:
private final IBinder binder = new MyBinder();
@Override
public IBinder onBind(Intent intent) {
return binder;
}
public class MyBinder extends Binder {
MyService getService() {
return MyService.this;
}
}
The connection between the Service and Activity is represented as a ServiceConnection.
You’ll need to implement a new ServiceConnection, overriding the onServiceConnected