屏幕关闭时重新启动应用程序

Question

当用户触摸屏幕时，我的应用程序正在完成。为此，在 onTouch() 方法中，我有

Intent intent = new Intent(getBaseContext(), FinActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
finish();

FinActivity 类：

public class FinActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);

        IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_ON);
        filter.addAction(Intent.ACTION_SCREEN_OFF);
        BroadcastReceiver mReceiver = new AlarmReceiver();
        registerReceiver(mReceiver, filter);

        Intent intent = new Intent(this, AlarmReceiver.class);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(
                this.getApplicationContext(), 234324243, intent, 0);

        AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
        alarmManager.setRepeating(AlarmManager.RTC_WAKEUP,
                System.currentTimeMillis() + (60 * 1000),
                System.currentTimeMillis() + (60 * 1000), pendingIntent);
        finish();
    }

我想在屏幕关闭时重新启动我的应用程序。我有这个 AlarmReceiver 类：

public class AlarmReceiver extends BroadcastReceiver {

    public static boolean wasScreenOn = true;

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

        if (intent.getAction().equals(Intent.ACTION_SCREEN_OFF)) {
            // do whatever you need to do here
            System.out.println("Screen OFF");
            wasScreenOn = false;

                Intent i = new Intent(context, SplashScreen.class);
        i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        context.startActivity(i);

        } else if (intent.getAction().equals(Intent.ACTION_SCREEN_ON)) {
            // and do whatever you need to do here
            System.out.println("Screen ONN");
            wasScreenOn = true;
        }
    }

}

但 60 秒后我在这一行得到 NullPointerException ： intent.getAction().equals(Intent.ACTION_SCREEN_OFF)

我的错误在哪里？我做错了什么？

提前致谢。

Answer 1

如果您只想知道屏幕是打开还是关闭，您可以使用 Android 的 PowerManager 类，它来自 api level 1。您可以使用 isScreenOn ()了解屏幕状态的方法。

您可以获取更多详细信息 http://developer.android.com/reference/android/ os/PowerManager.html 此处。