如何通过单击通知恢复以前的活动

contentIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | INTENT.FLAG_ACTIVITY_SINGLE_TOP);

我应该把这个放在我的代码里?我试过了,但没用。请帮帮我!

        ns = Context.NOTIFICATION_SERVICE;
        mNotificationManager = (NotificationManager) getSystemService(ns);
        icon = R.drawable.icon;
        tickerText = "Short Msg";
        when = System.currentTimeMillis();
        notification = new Notification(icon, tickerText, when);
        context = getApplicationContext();
        contentTitle = "MyApp";
        contentText = "Reopen App";
        notification.defaults |= Notification.DEFAULT_SOUND;
        notification.defaults |= Notification.DEFAULT_VIBRATE;
        notificationIntent = new Intent(this, StartTimer.class);
        contentIntent = PendingIntent.getActivity(this, 0, notificationIntent, 0);
        notification.setLatestEventInfo(context, contentTitle, contentText, contentIntent);