How to subclass UIApplication ?

Question

The iPhone Reference Libary - UIApplication says I can subclass UIApplication, but if I try this I will get an exception:

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'There can only be one UIApplication instance.'

This reminds me of the Highlander "There can be only one,. :-)

Do I have to pass other argurments to UIApplicationMain? Or did I missread somthing in the libary?

Answer 1

In your app's info.plist, make sure you change the NSPrincipalClass key to the name of your subclass. This'll make Cocoa instantiate the correct class when the applications loads - you shouldn't have to do anything other than that to get your subclass working.

Answer 2

Did you pass name of your subclass to UIApplicationMain? assume you have

@interface MyUIApp : UIApplication 
...

and then in main():

NSString* appClass = @"MyUIApp";
NSString* delegateClass = nil;
int retVal = UIApplicationMain(argc, argv, appClass, delegateClass);