Add a ViewController to a view inside a Window based application

Ok this is an easy one for most of you and a pretty basic question, but I quite don't get the full concept yet .

I've got a window based application, it contains 2 views, so far s开发者_开发技巧o good, everything is working but now I`m trying to do a modalTransition, which requires a ViewController ( which I don't have ) . What is the best way to attach a ViewController to one of those existing views in my Window so I can start playing with ModalTransitions ?

Thanks !

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You should declare your navigation controller to your AppDelegate. There is a good video tutorial in Youtube which combines navigation controller and tab bar, check it if you want:video