有人能解释一下BroadcastReceiver
和WakefulBroadcastReceiver
之间的确切区别吗
在什么情况下,我们必须使用每个接收器类?
发布于 2014-10-15 19:03:23
BroadcastReceiver
和WakefulBroadcastReceiver
之间只有一个区别。
当您接收到onReceive()
方法内部的广播时,
假设,
BroadcastReceiver:
如果你启动了一些长时间运行的进程,你不能保证
WakefulBroadcastReceiver:
在您启动completeWakefulIntent
.之前,
示例:
在这里,当您接收广播时,您正在启动一个服务,因为您正在使用WakefulBroadcastReceiver
,它将保持wakelock
,并且不会让CPU休眠,直到您完成服务内部的工作并触发completeWakefulIntent
代码:
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);
}
}
https://stackoverflow.com/questions/26380534
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