Call a method from AppDelegate - Objective-C

Question

I was trying to call an existing method of my ViewController.m from AppDelegate.m inside the applicationDidEnterBackground method,

Answer 1

The view controller is already instantiated as part of the NIB/storyboard process, so if your app delegate does its own alloc/init, you are simply creating another instance (which bears no relation to the one created the NIB/storyboard).

The purpose of the construct you outline is merely to give the app delegate a reference to the view controller that the NIB/storyboard instantiated for you.