title: Share background view between tabs on a UITabBarController
body: <p>Is it possible to have the same background between tabs on a UITabBarController without having to set the same background on all the views? I want to put a view in the background that periodically does a very short, non-resource intensive animation. When switching tabs, I'd like that animation to persist. I've read how to do it for UINavigationControllers, but haven't found any tips for a UITabBarController.</p>