View hierarchy in iPhone question

I'm not going to say this is good design by any means. I'm kind of inheriting something that is existing. Anyway, there is a TabController. One this one tab, there are two views that get loaded on demand based on a UISegmentController. Both of these two ViewControllers are subclasses of another ViewController that has methods I need.

When I'm in the TabController, I want to create a method that uses some of the superclass methods of the two ViewControllers. How do I get access to the tab's current ViewController since it's loaded on demand? Do I need to have a reference of the base controller ty开发者_如何学编程pe, and just have it set to the current view controller when it gets loaded on demand? Thanks.

To get the active tab showing on the screen, you could use [self.tabBarController selectedViewController] which will give you a UIViewController Reference. If you want to use the methods then you can cast it to your ViewController Superclass and then call methods on it like so (where self.tabBarController is your Tab Bar Controller):

MySuperClassViewController *viewC = (MySuperClassViewController *)[self.tabBarController selectedViewController];
[viewC someMethodDeclaredHere];

First, a little bit of terminology to clear up some potential confusion: I assume you mean a UITabBarController which controls various view controllers. Also, it seems you are using a UISegmentedControl which is not a view controller but a subclass of UIView. I hope these are just typos and not conceptional problems.

There is still some ambiguity about what you mean with "when I am in the tab controller". I assume you want to put code into the class representing the UITabBarController. But why? Just put these methods into the appropriate view controller, or if it is something that has to be done before, into your app delegate. However, if these methods are in a view controller superclass, they should have something to do with the logic necessary for this view controller.

If you need the methods elsewhere, i.e. outside your view controllers, consider creating a separate #include file and putting the methods there. Alternatively, you can use your app delegate which is conveniently accessible through [[UIApplication sharedApplication] delegate].