NSNotification is being called multiple times from UITabBarController

Question

I have a UITabBarController, which has 4 tabs. Each one of those tabs is a separate UIViewController. I have objects on each one of those 4 VC\'s t

Answer 1

it should be called only once so that it never gets called again

static dispatch_once_t onceToken;

dispatch_once(&onceToken, ^{
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(methodName:) name:@"name" object:nil];
});