android - 设备可以在前台服务之前休眠吗？

Question

我知道以前我们需要使用 WakefulBroadcastReceiver 来确保在接收器 onReceive 和服务 onHandleIntent 之间设备不会再次进入休眠状态.

现在 Google 似乎已经弃用了 WakefulBroadcastReceiver，因为从接收器启动服务不再“正确”。

我正在做的一件事是从高优先级 FCM 通知启动前台服务。这在新的后台执行规则下是完全有效的。但由于 WakefulBroadcastReceiver 已被弃用，这是否意味着 startForegroundService 保证设备在 onReceive 和 onHandleIntent 之间保持足够长的唤醒时间？唤醒锁？或者我应该只在接收器中手动持有唤醒锁并将其发送到服务以释放？

Answer 1

Does that mean startForegroundService guarantees that device stays awake long enough between onReceive and onHandleIntent's wakelock?

没有。

Or should I just hold a wakelock manually in the receiver and send it to the service to release?

您可以在服务的 onCreate() 中请求部分唤醒锁，如下所示:

private PowerManager.WakeLock wakeLock;
@Override
public void onCreate() {
    super.onCreate();
    final PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
    wakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, PARTIAL_WAKE_LOCK_TAG);
    ...
}

请记住在使用后或在 onDestroy() 中释放唤醒锁，如下所示:

@Override
public void onDestroy() {
    super.onDestroy();      
    if (wakeLock.isHeld()) {
        wakeLock.release();
    }
}

Google 建议避免使用唤醒锁，因为它会耗尽用户的电池电量。有多种 API 可用于各种用例。基于documentation ，您可以考虑以下备选方案:

• If your app is performing long-running HTTP downloads, consider using DownloadManager.
• If your app is synchronizing data from an external server, consider creating a sync adapter.
• If your app needs to execute background tasks at regular intervals, consider using JobScheduler or Firebase JobDispatcher. For information on triggering tasks at specific intervals, see Intelligent Job-Scheduling.