Notification with "null" PendingIntent

I'm trying to implement notification in Android.

Now I have a problem, I don't want to have 开发者_运维知识库a PendingIntent that user will open any Activity. How can I do that?

PendingIntent contentIntent = PendingIntent.getActivity(
    getApplicationContext(),
    0,
    new Intent(), // add this
    PendingIntent.FLAG_UPDATE_CURRENT);

The following works and seems more straightforward:

PendingIntent pi = PendingIntent.getActivity(context, 0, null, 0);

Having a notification without launching a subsequent Activity seems quite sensible to me - eg "Its time to get up!.