nsnotifications

I have an objective C class. In it, I created a init method and set up a NSNotification in it //Set up NSNotification [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(getData) name:@"Answer Submitted" object:nil]; Where do I set the [[NSNotificationCenter defaultCenter] removeObserver:self] in this class? I know that for a UIViewController , I can add it into the viewDidUnload method So what needs to be done if I just created an objective c Class? The generic answer would be "as soon as you no longer need the notifications". This is obviously not a satisfying answer. I

I am trying to pass an object from my app delegate to a notification receiver in another class. I want to pass integer messageTotal . Right now I have: In Receiver: - (void) receiveTestNotification:(NSNotification *) notification { if ([[notification name] isEqualToString:@"TestNotification"]) NSLog (@"Successfully received the test notification!"); } - (void)viewDidLoad { [super viewDidLoad]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(dismissSheet) name:UIApplicationWillResignActiveNotification object:nil]; [[NSNotificationCenter defaultCenter] addObserver:self

What are the pros and cons of each of them? Where should I use them specifically? The rule of thumb here is how many clients would like to be notified of an event. If it's mainly one object (e.g. to dismiss a view or to act upon a button clicked, or to react to a failed download) then you should use the delegate model. If the event you emit may be of an interest to many objects at once (e.g. screen rotated, memory usage, user login/logout), then you should use the NSNotificationCenter . Their purposes are different: Notification is used to broadcast messages to possibly several recipients

I'm implementing socket.io in my swift ios app. Currently on several panels I'm listening to the server and wait for incoming messages. I'm doing so by calling the getChatMessage function in each panel: func getChatMessage(){ SocketIOManager.sharedInstance.getChatMessage { (messageInfo) -> Void in dispatch_async(dispatch_get_main_queue(), { () -> Void in //do sth depending on which panel user is }) } } However I noticed it's a wrong approach and I need to change it - now I want to start listening for incoming messages only once and when any message comes - pass this message to any panel that