I have a UINavigationController Stack like this :

UINavigationController -> RootViewController-> OtherControllers->...

I wanna the UINavigationBar background color

• set to red color when the RootViewController is displaying
  (topmost in the UINavigationController’s stack) .
• set to green color when the non-RootViewController is displaying
  in the UINavigationController.

Is there any nice way to do this kind of work (other than set the bar tint color manually for each controller)?