NSNotification 예제

// remove notification observer
[[NSNotificationCenter defaultCenter] removeObserver:self];

// add notification observer
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(default:) name:kDefault object:nil];

// post notification
[[NSNotificationCenter defaultCenter] postNotificationName:kDefault object:nil];

// post notification with object
NSDictionary* dict = [NSDictionary dictionaryWithObject:_chatField.text forKey:@"chatText"];
        [[NSNotificationCenter defaultCenter] postNotification:
         [NSNotification notificationWithName:@"chatText"
                                       object:self
                                     userInfo:dict]];

// example
- (void)updateLocationOnMapView:(NSNotification *)notification
{
    NSString *chatText = [notification.userInfo objectForKey:@"chatText"];
   
    NSLog(@"received chat text : %@", chatText);
}