安卓点亮屏幕

Question

我制作了一个由 AlarmManager 安排 Activity 启动的应用程序。即使屏幕关闭并且设备被锁定，我也想出现。

要实现这一点，请设置窗口标志

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
        | WindowManager.LayoutParams.FLAG_ALLOW_LOCK_WHILE_SCREEN_ON);

尝试获取屏幕锁

if(_lock == null)
{
    PowerManager pm = (PowerManager)App.getAppContext()
            .getSystemService(Context.POWER_SERVICE);

    _lock = pm.newWakeLock(
            PowerManager.FULL_WAKE_LOCK, "ScreenOn");
    _lock.acquire();
}

_lock是PowerManager.WakeLock，在onPause时释放

protected void onPause()
{
     if(_lock != null)
     {
          _lock.release();
     }
}

这段代码在onCreate和onRestart中执行。如果 Activity 尚未启动，一切正常。

但如果它较早启动，则屏幕不会关闭。

• onRestart 首先被调用
• 然后调用 onResume
• 立即调用 onPause

所以 Activity 没有启动。我的问题是在这种情况下如何打开屏幕。 (我正在使用 API 15)。

Answer 1

我想到了解决方案。我创建了一个新 Activity ，它将尝试在 onCreate() 中打开屏幕，然后等待它打开。当屏幕正常时，它将启动应该显示的 Activity 。使Android始终创建此 Activity

public class TurnOnScreen extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
        if (pm.isScreenOn()) openActivity();
        else {
            registerReceiver(mScreenOnReceiver, new IntentFilter(
                    Intent.ACTION_SCREEN_ON));
            reciever_registered = true;
            turnScreenOn();
        }
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        if (reciever_registered) {
            unregisterReceiver(mScreenOnReceiver);
            reciever_registered = false;
        }
    }

    private boolean reciever_registered = false;
    private final BroadcastReceiver mScreenOnReceiver = new BroadcastReceiver() {

        @Override
        public void onReceive(Context context, Intent intent) {
            openActivity();
        }
    };

    private void openActivity() {
        Intent intent = new Intent();
        // ....
        finish();
    }

    private void turnScreenOn() {
        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
                | WindowManager.LayoutParams.FLAG_ALLOW_LOCK_WHILE_SCREEN_ON);
    }
}

我还在寻找为什么onRestart没有亮屏的解释。