如何显示屏幕已锁定？

在我的应用程序中，我需要知道设备何时被锁定（在 HTC 上，它看起来像是短按“电源”按钮）。那么问题是：设备锁定时会触发哪个事件？或者设备将要休眠？

你应该延长BroadcastReceiver并实施onReceive， 像这样：

public class YourBroadcastReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        if (Intent.ACTION_SCREEN_OFF.equalsIgnoreCase(intent.getAction())) {
            //screen has been switched off!
        }
    }
}

然后你只需注册它，当屏幕关闭时你就会开始接收事件：

IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_ON);
filter.addAction(Intent.ACTION_SCREEN_OFF);
appBroadcastReceiver = new AppBroadcastReceiver(yourActivity);
registerReceiver(appBroadcastReceiver, filter);