how can I animate the UINavigationBar background change on UIViewController push?

Question

My app uses two different backgrounds for the UINavigationBar to indicate to the user what level in the hierarchy they\'re at. When I push a UIViewController that needs the

Answer 1

I know this is an old thread, but this worked for me:

CATransition *transition = [CATransition animation];
transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
transition.type = kCATransitionFade;
transition.duration = 0.5;

[self.navigationController.navigationBar.layer addAnimation:transition forKey:nil];
[self.navigationController.navigationBar setBackgroundImage:[[UIImage imageNamed:@"navigationbar.png"]resizableImageWithCapInsets:UIEdgeInsetsMake(44, 20, 44, 20)] forBarMetrics:UIBarMetricsDefault];        

Place this inside your viewDidLoad method. You'll need to link/import the QuartzCore framework.