Accessing AppDelegate Properties from View Controller | iOS Programmer Guide

UIApplication has a delegate property which needs to be tycasted to your application object. Then we can able to access it in any view controller.

[UIApplication sharedApplication].delegate

You'll also need to include the app delegate header file in your view controller and possibly typecast the delegate from id to your actual app delegate class as below:

#include "MyAppDelegate.h"

((MyAppDelegate *)[UIApplication sharedApplication].delegate).myProperty;