I've customized UIBarButtonItem in my AppDelegate.m using UIAppearance and all the bar buttons are showing the correct images in normal and selected states.
I want "Done" and "Save" buttons to use a different image (so they appear to be blue instead of gray), so I use -setBackgroundImage: forState: barMetrics to set two different images for UIControlStateNormal and UIControlStateSelected in -viewDidLoad.
The image for UIControlStateNormal is working fine, but the UIControlStateSelected one isn't showing, instead it shows the original image I used for selected states in AppDelegate.m. If I comment out the original image the new (blue) one is shown properly.
What's the proper way to set different background images for specific buttons?
I believe UIControlStateHighlighted is what you are looking for.
A UIBarButtonItem goes into the highlighted state whenever it receives the user touch. UIControlStateSelected is typically for UI elements which toggle between two states.