nsnotificationcenter

Within an App I make use of several viewcontrollers. On one viewcontroller an observer is initialized as follows: [[NSNotificationCenter defaultCenter] removeObserver:self name:@"MyNotification" object:nil]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(myMethod:) name:@"MyNotification" object:nil]; Even when removing the NSNotification before initializing the number of executions of myMethod: is being summed up by the amount of repeated views on the respective viewcontroller. Why does this happen and how can I avoid myMethod: being called more then once. Note: I

I've read everything I could find on this topic and still cant figure out my issue. I have tried pausing my game in every area of appdelegate func applicationWillResignActive(application: UIApplication!) { NSNotificationCenter.defaultCenter().postNotificationName("pauseGameScene", object: self) } func applicationDidEnterBackground(application: UIApplication!) { NSNotificationCenter.defaultCenter().postNotificationName("pauseGameScene", object: self) } func applicationWillEnterForeground(application: UIApplication!) { NSNotificationCenter.defaultCenter().postNotificationName("pauseGameScene",

Is it ok to use of a notification to communication back to the main thread of an IOS app? (cf performSelectorOnMainThread). That is, there are are there any gottcha's for this purpose? Background want to call back to main UI thread from a background thread (e.g. performSelectorInBackground) could use performSelectorOnMainThread to communicate back, but wondering if it is OK to use a notification? For example [[NSNotificationCenter defaultCenter] postNotificationName:@"ModelChanged" object:self]; Actually there is a gottcha; you'll crash randomly! That has been my experience. This has to do

In my model I have an array of objects called events. I would like my controller to be notified whenever a new object is added to events. I thought that a good way to do this would be use the KVO pattern to get notified when the events changes (from a new object being added) // AppDelegate // events is a NSMutableArray @property/@synthesize etc... [appDelagate addObserver:self forKeyPath:@"events" options:NSKeyValueObservingOptionNew context:NULL]; But the observeValueForKeyPath method wasn't being called and I discovered that Arrays are not KVO compliant :-( One option is to manually trigger

I have an NSOperation. When it is finished I fire a NSNotificationCenter to let the program know that the NSoperation is finished and to update the gui. To my understanding listeners to the NSNotification will not run on the main thread because the NSOperation is not on the main thread. How can I make it so that the listeners run on the main thread when I fire my event? [[NSNotificationCenter defaultCenter] postNotificationName:@"myEventName" object:self]; You can use performSelectorOnMainThread:withObject:waitUntilDone: with using a helper method, in a similar fashion to the following example

I am, creating a app in which i need to show message to user that you received sms , is it possible using NSNotificationCenter. Please help? It's not possible, as far as I know. iOS treats a new SMS very similarly to a push notification sent to the system, and your code doesn't get notified of push notifications that are not sent to your app. To reiterate, iOS does not notify your app when an SMS (text message) has been received by your phone. 来源： https://stackoverflow.com/questions/9100242/can-my-app-knows-that-i-received-a-sms-on-my-iphone-using-notification-center