CODEWITHSUNDEEP
iosuiviewcontrollernsnotificationcenterdeallocobservers
sudhanshu-shishodia
sudhanshu-shishodia

Reputation: 1108

iOS - Using dealloc to remove observer

I have a basic question regarding removing observer.

I have a ViewController parent class which is inherited by 3 ViewController child classes. eg. BookVC -> BookHotelVC, BookFlightVC, BookTrainVC

Here, I added an observer in the viewDidLoad of parent class (I do [super viewDidLoad] in child ViewControllers) which notifies a method written in parent class. My code-

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(BookingCompleted:) name:@"BookingCompleted" object:nil];

Now I want to remove the observer when I move away from any of the child ViewControllers, but I can't write [super dealloc] in dealloc of each child ViewController because ARC doesn't permit this.

How can I remove the observer which is set ? Because whenever I move to child ViewController, a new observer is added which causes weird things (like, calling that method twice/thrice... - invoking alert twice/thrice...).

Kindly suggest.

Upvotes: 0

Views: 744

Answers (2)

Kevin DiTraglia
Kevin DiTraglia

Reputation: 26068

Removing the observers in dealloc is fine, do not call [super dealloc] (as you saw, with ARC enabled, the compiler won't let you), simply write:

- (void)dealloc {
    [self removeYourObservers];
}

Upvotes: 1

Aaron Wojnowski
Aaron Wojnowski

Reputation: 6480

Just don't call super! In ARC it's not required (see http://clang.llvm.org/docs/AutomaticReferenceCounting.html#dealloc).

-(void)dealloc {

    [[NSNotificationCenter defaultCenter] removeObserver:self];

}

Upvotes: 0

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