Getting a reference to the UIApplication delegate

Question

I'm writing my first iPhone application and I'm having trouble switching views. I have 2 views and a reference to each in the AppDelegate (an instance of UIApplicationDelegate). I create instances of both in the applicationDidFinishLaunching and immediately show the first view. This works fine.

The problem is the reference to the other view is in the AppDelegate and I can't figure out how to get a reference to it so I can switch to the other view. Is there a way to get a reference to the main UIApplication or UIApplicationDelegate objects?

score 109 · Accepted Answer · edited Apr 11 '17 at 08:11

109

Yes, UIApplication is a singleton, and uses the normal singleton pattern for Objective-C:

[UIApplication sharedApplication];

You can get your delegate class directly from it:

MyAppDelegate *delegate = (MyAppDelegate *)[[UIApplication sharedApplication] delegate];

edited Apr 11 '17 at 08:11

Kerem Baydoğan

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answered Jul 26 '09 at 10:13

Louis Gerbarg

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it may be obvious but worth noting that MyApplicationDelegate is the name of the class that conforms to the protocol **UIApplicationDelegate**, in many cases **AppDelegate** – Mehdi Ijadnazar Nov 05 '15 at 14:45
I am trying this but getting errors. AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate]; 'sharedApplication' is unavailable: not available on iOS (App Extension) - Use view controller based solutions where appropriate instead. – Akbar Khan Jul 04 '21 at 17:50

score 19 · Answer 2 · answered Jul 26 '09 at 10:12

19

Use:

[[UIApplication sharedApplication] delegate];

answered Jul 26 '09 at 10:12

Codebeef

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Getting a reference to the UIApplication delegate

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