Is it possible to insert an animation into an UITabBarController thats shown when switching Views?

Question

I have a custom UITabBarController and I want it to slide out the old view and slide in the new view whenever a TabBarItem gets pressed. I looked at UITabBarControllerDelegate but it just offers me to decide if the view gets displayed not how (via shouldSelectViewController). Is there a way to do that?

(My goal is to have a starfield background that looks almost the same on all the 4 views. It should look like the items get changed and the background just scrolls by a little)

Answer 1

Subclass UITabBarController and make it it's own delegate. Now you can intercept methods like tabBarController:shouldSelectViewController: and manipulate any custom views you have added to the tab bar. And if you add your starfield to the tab bar view, and then use tab controllers that have translucent views the common background can show through.

And you can even intercept tab bar controller methods directly like setSelectedIndex: to have even more control to let you fade things out. But just make sure that you call the super version of the method at some point if you do this so the tab bar remains functional.