How do I check if an UIViewController is currently being displayed?

Question

How do I check if an UIViewController is currently being displayed?

My UIViewControllers are listening for NSNotifications - e

Answer 1

You need to check if your viewcontroller is on top of the stack of navigationcontroller's viewcontroller array. A sample code is,

if (self.navigationController.topViewController == self) {
    //the view is currently displayed
}

You can use this inside the viewWillAppear method to check whether the current view is visible.