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POWhy is my NSNotification its observer called multiple times?
 

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  1. POWhy is my NSNotification its observer called multiple times?
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    <p>Within an App I make use of several viewcontrollers. On one viewcontroller an observer is initialized as follows:</p> <pre><code>[[NSNotificationCenter defaultCenter] removeObserver:self name:@"MyNotification" object:nil]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(myMethod:) name:@"MyNotification" object:nil]; </code></pre> <p>Even when removing the <code>NSNotification</code> before initializing the number of executions of <code>myMethod:</code> is being summed up by the amount of repeated views on the respective viewcontroller.</p> <p>Why does this happen and how can I avoid myMethod: being called more then once.</p> <p>Note: I made sure by using breakpoints that I did not made mistakes on calling postNotification multiple times.</p> <p>Edit: This is how my postNotification looks like</p> <pre><code>NSArray * objects = [NSArray arrayWithObjects:[NSNumber numberWithInt:number],someText, nil]; NSArray * keys = [NSArray arrayWithObjects:@"Number",@"Text", nil]; NSDictionary * userInfo = [NSDictionary dictionaryWithObjects:objects forKeys:keys]; [[NSNotificationCenter defaultCenter] postNotificationName:@"myNotification" object:self userInfo:userInfo]; </code></pre> <p>edit: even after moving my subscribing to viewwillappear: I get the same result. myMethod: is called multiple times. (number of times i reload the viewcontroller).</p> <pre><code>-(void)viewWillAppear:(BOOL)animated { [super viewWillAppear:animated]; [[NSNotificationCenter defaultCenter] removeObserver:self name:@"MyNotification" object:nil]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(myMethod:) name:@"MyNotification" object:nil]; } </code></pre> <p>edit: something seems wrong with my lifecycle. ViewDidUnload and dealloc are not getting called, however viewdiddisappear is getting called.</p> <p>The way I push my Viewcontroller to the stack is as follows where parent is a tableview subclass (on clicking the row this viewcontroller is initiated:</p> <pre><code>detailScreen * screen = [[detailScreen alloc] initWithContentID:ID andFullContentArray:fullContentIndex andParent:parent]; [self.navigationController pushViewController:screen animated:YES]; </code></pre> <p>Solution:</p> <p>Moving removal of nsnotification to viewdiddisappear did the trick. Thanks for guidance!</p>
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