Question

How do you remove an observer from an object under ARC? Do we just add the observer and forget about removing it? If we no longer manage memory manually where do we resign from observing?

For example, on a view controller:

[self.view addObserver:self
            forKeyPath:@"self.frame"
               options:NSKeyValueObservingOptionNew 
               context:nil];

Previously, I would call removeObserver: in the view controller’s dealloc method.

Answer 1

You still can implement -dealloc under ARC, which appears to be the appropriate place to remove the observation of key values. You just don’t call [super dealloc] from within this method any more.

If you were overriding -release before, you were doing things the wrong way.