BroadcastReceiver Vs WakefulBroadcastReceiver

There is only one difference between BroadcastReceiver and WakefulBroadcastReceiver.

When you receive the broadcast inside onReceive() method,

Suppose,

BroadcastReceiver :

• It is not guaranteed that CPU will stay awake if you initiate some long running process. CPU may go immediately back to sleep.

WakefulBroadcastReceiver :

• It is guaranteed that CPU will stay awake until you fire completeWakefulIntent.

Example:

Here, when you receive broadcast, you are starting a service, as you are using WakefulBroadcastReceiver, it will hold wakelock and won't let the CPU sleep until you finish the work inside service and fire completeWakefulIntent

Code:

public class SimpleWakefulReceiver extends WakefulBroadcastReceiver {    @Override    public void onReceive(Context context, Intent intent) {        // This is the Intent to deliver to our service.        Intent service = new Intent(context, SimpleWakefulService.class);        // Start the service, keeping the device awake while it is launching.        Log.i("SimpleWakefulReceiver", "Starting service @ " + SystemClock.elapsedRealtime());        startWakefulService(context, service);    }}class SimpleWakefulService extends IntentService {    public SimpleWakefulService() {        super("SimpleWakefulService");    }    @Override    protected void onHandleIntent(Intent intent) {        // At this point SimpleWakefulReceiver is still holding a wake lock        // for us.  We can do whatever we need to here and then tell it that        // it can release the wakelock.  This sample just does some slow work,        // but more complicated implementations could take their own wake        // lock here before releasing the receiver's.        //        // Note that when using this approach you should be aware that if your        // service gets killed and restarted while in the middle of such work        // (so the Intent gets re-delivered to perform the work again), it will        // at that point no longer be holding a wake lock since we are depending        // on SimpleWakefulReceiver to that for us.  If this is a concern, you can        // acquire a separate wake lock here.        for (int i=0; i<5; i++) {            Log.i("SimpleWakefulReceiver", "Running service " + (i+1)                    + "/5 @ " + SystemClock.elapsedRealtime());            try {                Thread.sleep(5000);            } catch (InterruptedException e) {            }        }        Log.i("SimpleWakefulReceiver", "Completed service @ " + SystemClock.elapsedRealtime());        SimpleWakefulReceiver.completeWakefulIntent(intent);    }}