A Service is a component that performs operations in the background without a user interface. (such as download a file)
You start a service by passing an intent.
startService(MyService)
stopService(MyService)
Default Services have a higher priority that background activity.
A service has its own context.
To wake it self up, you need to implement a broadcast receiver. It will receive a PendingIntent (Intent with permission) from the Alarm Manager.
| Priority | Activity Type | Service Type |
|---|---|---|
| Critical | Active | Foreground |
| High | Visible | Running (Default) |
| Low | Background | Na |
Any background app will be killed as needed from older to newer.
public class MyService extends Service {
@Override
public void onCreate() { ....}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
// Set the service as a foreground activity,
// therefore increasing its priority
// and decreasing its chance to be killed (mainly impossible)
startForeground(notification);
// TODO: Initiate background Task
return Service;
}
@Override
public void onDestory() { .... }
@Override
public IBinder onBind(Intent intent) {
return null;
}
}
Service run on the main thread then you need to use a background running thread to do what you want to do within your service.
The IntentService class implements a background thread pattern with a intent queue. The service start when an intent is received and stop when the queue is empty.
Intent intent = new Intent(getActivity(), myService.class);
// Pass a value to the service that can be retrieved with intent.getStringExtra(KEY_VALUE);
intent.putExtra(myService.KEY_VALUE,"value");
// Start the service (ie place the intent in the service queue)
getActivity().startService(intent);
public class MyIntentService extends IntentService
@Override
protected void onHandleIntent(Intent intent) {
// TODO: Task to be performed
}
}
Performing data sync operations. See Android - Sync Manager Framework (SyncAdapter)
As a service is a component, it must be declared in the AndroidManifest.xml file
<service android:name="com.example.myapp.service.myService"/>