Is NSNotificationCenter removeObserver in ARC needed?

Question

Does adding an observer increase the retain count of an object? If yes, does ARC handle the removing of this observer too? If not, where should I remove the observer?

Solution

You should explicitly remove the observer even you use ARC. Create a dealloc method and remove there..

-(void)dealloc {
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

If you see the method you don't need to call [super dealloc]; here, only the method without super dealloc needed.

UPDATE for Swift

You can remove observer in deinit method if you are writing code in swift.

deinit {
        NSNotificationCenter.defaultCenter().removeObserver(self)
       }

Comments

[Adam]

See this question.

[Anoop Vaidya]

This is same as I asked few months back :)

[amergin]

I think it's valid re-asking these questions as I prefer to look for the newest answers to questions in case the perceived wisdom has changed.

[Jing]

I tested and found that not calling removeObserver in dealloc won't lead to crash when observed object post notifications. Since addObserver not retain observer, is it still need to removeObserver?

[Ricardo]

One question: When you call addObserver, is NSNotificationCenter retaining the observer or not? Thanks.

[holex]

the notification center won't hold strong references of the observers, so there is not necessary to remove them explicitly in ARC.

[Honghao Zhang]

It's do need to remove observer in deinit method. I've seen crashes related to NSNotificationCenter and it's resolved by removing observer

[Bradley Thomas]

This answer is outdated since iOS9, unregistering in dealloc is no longer needed, ref: useyourloaf.com/blog/…