Why doesn't Remove Observer from NSNotificationCenter:addObserverForName:usingBlock get called

Question

I\'m confused on why the observer is never removed in the following code. In my viewDidAppear I have the following:

-(void)viewDidAppear:(BOOL)animated{

id         


        

Answer 1

I find that in fact there is a memory leak unless the observer is marked both __block and __weak. Use Instruments to make sure that self is not being overretained; I bet it is. This, however, works correctly (from my actual code):

__block __weak id observer = [[NSNotificationCenter defaultCenter] 
    addObserverForName:@"MyMandelbrotOperationFinished" 
    object:op queue:[NSOperationQueue mainQueue] 
    usingBlock:^(NSNotification *note) {
        // ... do stuff ...
        [[NSNotificationCenter defaultCenter] 
            removeObserver:observer 
            name:@"MyMandelbrotOperationFinished" 
            object:op];
}];