Calling a method from another class

Hi there.

I’m rather new to Objective-C and objective oriented programming. I’ve tried to teach myself through books, but I seem to miss a basic concept here.

I think my problem is best explained through an example.


I’m trying to create a UINavigationController based application with some subviews. I want to use the toolbar, that’s provided with the UINavigationController, but I do not want it to show on all subviews. Just some of them.

Is start with the basic class “testAppDelegate.m/.h”, create an instance of the UINavigationController class with UINavigationController = *navigationController in that class. Now I add views and a navigationBar and everything works fine.

The toolbar isn’t showing yet, as it is hidden by default. If I change that via navigationController.toolbarHidden = NO then I see the toolbar, but I see it all the time.

So I create a subclass of UIViewController named myViewController. There I use the viewWillAppear Method to show the toolbar, when the view is pushed. But how do I do that. myViewController cannot access the navigationController created in testAppDelegate.


Any help for a newb?

My first instinct was to create a method in testAppDelegate that sets navigationController.toolbarHidden = NO. That works fine, but only if I call the method from within the class (via “self”). If I call the method from myViewController, the App crashes.