NSNotificationCenter Post to nil -> crash

Question

My TableViewCell register for Notifications. But i can't unregister because i don't know when. I tried to subclass NSNotificationCenter but i didn't tried it the right way.

Some Ideas how to fix this?

Answer 1

A classic approach would registering your notifications within a UIViewController derived class in viewDidLoad and unregistering in viewDidUnload.

For a UIView derived class, you should really think twice if you are going the right way (mixing display-logic- with business-logic-code). However, you could register in initWithFrame and unregister on dealloc.

Since UITableViewCell is UIView derived, the right places could be registering in initWithStyle and unregistering in dealloc as well (in case you are not reusing your cells).

Answer 2

The problem here is that UITableViewCell rarely gets dealloc'ed

Usually what you want is to call [[NSNotificationCenter defaultCenter] removeObserver:self] in your subclass' prepareForReuse method. (Be sure to call [super prepareForReuse]; in your implementation!)