The problem with NotificationCenter and KVO observers is that you have to remember to remove the observing object when it gets dealloc'ed or your app will crash on the next notification.
The methods below create a small "remover" object that is associated with the observer object such that when the observer object gets dealloc'ed this object will also get dealloc'ed and remove the observations.
N.B.: This class is designed to remove the observer when the observer is dealloc'ed. If you need to remove the observer before that then you should use the standard methods and be sure to handle the dealloc case yourself.
Instead of writing:
// Selector based
[[NSNotificationCenter defaultCenter] addObserver:notificationObserver
selector:notificationSelector
name:notificationName
object:notificationSender];
// Block based
[[NSNotificationCenter defaultCenter] addObserverForName:name
object:obj
queue:queue
usingBlock:block];
// KVO
[self addObserver:anObserver forKeyPath:keyPath options:options context:context];
you write:
// Selector based
[INTUAutoRemoveObserver addObserver:notificationObserver
selector:notificationSelector
name:notificationName
object:notificationSender];
// Block based
[INTUAutoRemoveObserver addObserver:self
forName:name
object:obj
queue:queue
usingBlock:block];
// KVO
[INTUAutoRemoveObserver addObserver:anObserver
forKeyPath:keyPath
options:options
context:context
onReceiverObject:self];
E.g.:
// Selector based
[INTUAutoRemoveObserver addObserver:self
selector:@selector(myMethod)
name:@"BroadcastNotification"
object:nil];
// Block based
MyObject* __weak weakSelf = self; // So the block doesn't retain us
[INTUAutoRemoveObserver addObserver:self
forName:@"BroadcastNotification"
object:nil
queue:[NSOperationQueue mainQueue]
usingBlock:^(NSNotification *note) {
[weakSelf observeMe];
}];
// KVO
[INTUAutoRemoveObserver addObserver:self // self or some observer object. When this is dealloc'ed then observer is removed.
forKeyPath:NSStringFromSelector(@selector(myProperty))
options:NSKeyValueObservingOptionNew
context:nil
onReceiverObject:self];
N.B.: If the observer is self you will see a error in the log file about the instance being deallocated while key
observers were still registered to it (even though they are removed as a side effect of self getting dealloc'ed)
when self is dealloc'ed.
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