Question

while reading cocoa fundamental guide i have gone through:

• (void)addObserver:(id)notificationObserver selector:(SEL)notificationSelector name:(NSString *)notificationName object:(id)notificationSender

I am getting all theories, but actually i am looking for a real example where it is used ?

Can any one give some sample example.

Actually i want to send some notifications to observers when some event occurs.

and i also want to know how observer catch/handle/receive that notification ??

Thanks

Answer 1

To listen for notifications, add code similar to this in the instance that you want to receive notifications:

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

When you want to post a notification:

[[NSNotificationCenter defaultCenter] postNotification:[NSNotification notificationWithName:@"SOME_NOTIFICATION_NAME" object:nil]];

I use code similar to this to update my UI while processing an in app purchase.