检查Android屏幕是否已锁定

Question

每当Android设备（运行Android 4.0以上）被锁定或解锁时，我都需要做一些事情。必要条件如下：

• 如果屏幕锁定设置为＆＃34;无＆＃34;，按下电源按钮并且屏幕熄灭时，我不认为设备被锁定。
• 如果屏幕锁定设置为＆＃34;无＆＃34;以外的任何其他设备，我认为当键盘锁定屏幕不存在时，设备将被解锁。

我已经实现了这段似乎适用于Android 5.0的代码，当＆＃34;无＆＃34;时，它会考虑the not-so-great behaviour of older Android versions。用来。在发布此问题之前，我还检查了其他问题，例如this one。

private class KeyguardWatcher extends BroadcastReceiver {
        public KeyguardWatcher() {
            IntentFilter intentFilter = new IntentFilter();
            intentFilter.addAction(Intent.ACTION_SCREEN_OFF);
            intentFilter.addAction(Intent.ACTION_SCREEN_ON);
            intentFilter.addAction(Intent.ACTION_USER_PRESENT);
            MyService.this.registerReceiver(this, intentFilter);
        }

        public void destroy() {
            MyService.this.unregisterReceiver(this);
        }

        @Override
        public void onReceive(Context context, Intent intent) {
            // Old Android versions will not send the ACTION_USER_PRESENT intent if
            // 'None' is set as the screen lock setting under Security. Android 5.0
            // will not do this either if the screen is turned on using the power
            // button as soon as it is turned off. Therefore, some checking is needed
            // with the KeyguardManager.
            final String action = intent.getAction();
            if (action == null) {
                return;
            }

            if (action.equals(Intent.ACTION_SCREEN_OFF)) {
                // If 'None' is set as the screen lock (ie. if keyguard is not
                // visible once the screen goes off), we do not consider the
                // device locked
                if (mKeyguardManager.inKeyguardRestrictedInputMode()) {
                    doStuffForDeviceLocked();
                }
            } else if (action.equals(Intent.ACTION_SCREEN_ON)) {
                if (!mKeyguardManager.inKeyguardRestrictedInputMode()) {
                    // The screen has just been turned on and there is no
                    // keyguard.
                    doStuffForDeviceUnlocked();
                }
                // If keyguard is on, we are to expect ACTION_USER_PRESENT when
                // the device is unlocked.
            } else if (action.equals(Intent.ACTION_USER_PRESENT)) {
                doStuffForDeviceUnlocked();
            }
    }
}

这似乎在Android 5.0中对我有用。我想知道在处理ACTION_SCREEN_OFF时是否有可能出现竞争条件。是否有可能除了＆＃34;无＆＃34;正在使用（例如＆＃34; Swipe＆＃34;）并且当我处理ACTION_SCREEN_OFF时，键盘锁不在限制输入模式中，但很快就会出现？如果是这种情况，我绝不会认为设备已锁定但可能是。