How does inheritance of NSNotificationCenter observers work? I have a parent class that several other classes end up subclassing. The parent class registers itself as an observer for a specific notification. I was under the impression that children would also be registered as observers as long as you invoke the super method where the registration happens. I happen to put it into viewDidLoad.
Do I need to re-register child classes are observers also and re-implement their delegate methods?
Each instance which calls -[super viewDidLoad] should end up receiving the notifications. You wouldn't need to override the notification-handling method as the superclass's implementation will be called. Of course if that's not sufficient in the subclass then you would have to provide an override.
You're registering objects, not classes, with notification centers. When you register for a notification, the callback method you register gets called on the object that registers, and if you've overridden it in a subclass, then the overridden method gets called.
If you're doing this in a subclass, ask yourself if the parent's code to register for the notification is getting called in the subclass.
This is all central to object-oriented programming and inheritance.