NSNotification - check if an observer is added before posting a notifiation

Question

my code is crashing at:

[[NSNotificationCenter defaultCenter] postNotificationName:kgotNotification object:dictionary];

my assumption is that I am posting a notification before the observer is added.

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(getItems:) name:kgotNotification object:nil];

is there a way to check for the list of active observers before posting a notification?

You can post notifications without having an observer. I imagine the problem with with your dictionary. — bbarnhart, Feb 17 '14 at 18:30
possible duplicate of [iPhone - testing if a notification exists](http://stackoverflow.com/questions/3799865/iphone-testing-if-a-notification-exists) — Xu Yin, Feb 17 '14 at 18:47
Is it possible an observer has been deallocated? Have you forgotten to implement `removeObserver` in `dealloc`? — James Webster, Mar 03 '14 at 12:51

score 2 · Accepted Answer · edited Feb 17 '14 at 19:10

2

You should do it like this:

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(getItems:) name:kgotNotification object:nil];
[[NSNotificationCenter defaultCenter] postNotificationName:kgotNotification object:self userInfo:dictionary];

Then your getItems Method:

-(void)getItems:(NSNotification* )note
{
    NSLog(@"UserInfo: %@", note.userInfo);
}

edited Feb 17 '14 at 19:10

jbouaziz

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answered Feb 17 '14 at 19:07

iCode

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@jbouaziz Thanks for your edit, silly mistake. – iCode Feb 17 '14 at 19:11

NSNotification - check if an observer is added before posting a notifiation

1 Answers1