iPhone flip right button (like iTunes)

Question

I'm trying to flip between two views. That's easy, the code is below, but I also want to simultaneously flip the button used to perform the flip.

You can see this behavior in the iPod application when you're playing a track; tapping the flip button flips between the cover art and the track listing, but it flips the button at the same time.

This is a page on the navigation controller, and the button I want to flip is the rightBarButtonItem.

Here's the code I have so far. This flips the view, but not the rightBarButton.

[UIView setAnimationBeginsFromCurrentState: YES];
[UIView setAnimationDuration: 0.5f];
[UIView setAnimationCurve: UIViewAnimationCurveEaseInOut];
showingBackside = !showingBackside;
if (showingBackside) {
    [UIView setAnimationTransition: UIViewAnimationTransitionFlipFromLeft
                           forView: self.view
                             cache: YES];
    [self.view addSubview: backside.view];
    [frontside.view removeFromSuperview];
} else {
    [UIView setAnimationTransition: UIViewAnimationTransitionFlipFromRight
                           forView: self.view
                             cache: YES];
    [self.view addSubview: frontside.view];
    [backside.view removeFromSuperview];
}
// flip image, too
NSString *newImage = showingBackside ? @"backside.png" : @"frontside.png";
[(self.navigationItem.rightBarButtonItem) setImage: [UIImage imageNamed: newImage]];
[UIView commitAnimations];

(The image flipping code here may not compile; I added it after to try to explain what I was trying to do.)

Where I'm running into trouble is I want to change the rightmost button in the navigation controller so it flips simultaneously.

How do I do this? What view do I animate, and do I do it as part of the same animation block or as a separate one? Any tips would be appreciated, I definitely don't have a good handle on animation yet.

Answer 1

There's some discussion here, but the solution is not so elegant.

First of all, since UIBarButtonItem is not a descendant of UIView, you probably cannot use UIKit animations directly on the UIBarButtonItem. However, you can try setting a customView and animating that. You can use the same animation block.