唤醒锁只能使用一次

Question

I created a Service that catches incoming notifications. Whenever a whatsapp notification appears the screen should be woken up and an activity is started. This works fine the first time, but then the screen just stays in sleep mode and the activity runs when I unlock the phone.

The Service Code: I declare the variables here:

@TargetApi(26)
public class NLService extends NotificationListenerService {

    private String TAG = this.getClass().getSimpleName();
    public PowerManager pm;
    public PowerManager.WakeLock wl;

the wakelock code in the onCreate function:

pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
wl = pm.newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK | PowerManager.ACQUIRE_CAUSES_WAKEUP, "callOverlay:wakeScreenNotification");

and in the onNotificationPosted function: [getting the notification content etc...]

try {
    //wake up screen
    wl.acquire();
    //run activity
    dialogIntent.putExtra("SERVICE", "whatsapp");
    new android.os.Handler().postDelayed( new Runnable() {
        public void run() {                              
            dialogIntent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT | Intent.FLAG_ACTIVITY_SINGLE_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
            startActivity(dialogIntent);
         }
    }, 600);
} catch (Exception e) {
    Log.i(TAG,"ERROR: "+e);
} finally {
    wl.release();
}

inside the activity I added following code inside the onCreate function:

final Window win= getWindow();
win.addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED | WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD);
win.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON | WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);

I'm new to android development. What am I missing? Thanks!

Answer 1

It turns out that the flag combination

FLAG_SHOW_WHEN_LOCKED | FLAG_DISMISS_KEYGUARD | FLAG_TURN_SCREEN_ON

only takes effect (turns on the screen & dismisses the keyguard) once per Activity . Contrary to my above comment, removing and re-applying the flags does not work.

If you want the screen/wake changes to take effect a second time, you have to create a new Activity, and apply the same flags to it.

If the user manually changes the phone state (by moving to another Activity or by turning the screen off/locking the phone), this also causes the flags to lose their effect.