Is it OK to use 'private' NSNotification names?

Question

I am implementing a drop-in component for iOS that lets you present a slide-in notification view. To make it short: I need to respond to events where NSNavigationController is pushing or popping windows.

I am currently listening to UINavigationControllerWillShowViewControllerNotification, which is not in the documentation but can easily be found when listening for all notification names (using the nil paramter for name).

The question is: Will that pass App Review or will the app get rejected?

I am aware and OK with with the fact that Apple might change the notification name, etc., but as a drop-in cannot always be the UINavigationController's delegate, I don't see another solution right now.

Thanks for your help,

Christian

UPDATE

Official Apple documentation does not explicitly forbid registering for all notifications being sent to yout app. Technically, it doesn't make much difference whether you register for all notifications and check for the notification name or whether you just register for that specific notification. After all, it might even result in a very little performance improvement

Answer 1

The answer is that it is not ok to listen for this notification and it may lead to rejection of your app. Apple clearly says that you should not use APIs which are not exposed.

You should use navigationController:willShowViewController:animated: method of UINavigationControllerDelegate protocol to know when the UINavigationController shows a view controller. You can post your own notification there to let your other objects know about the event.