Animate an UIBarButtonItem that has been assigned a UIButton as its customview. The UIButton uses an image that is mirrored on the X axis hence appear as if it's rotating.

gistfile1.txt

-(IBAction)tap:(id)sender
{
    UIBarButtonItem *refresh = self.navigationItem.rightBarButtonItem;

    CALayer *layer = ((UIButton*)refresh.customView).imageView.layer;

    CABasicAnimation *rotate = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
    rotate.timingFunction = [CAMediaTimingFunction functionWithName: kCAMediaTimingFunctionLinear];
    rotate.fromValue = @(0);
    rotate.toValue = @(2 * M_PI);
    rotate.duration = 1.0;
    rotate.repeatCount = HUGE_VALF;
    [layer addAnimation:rotate forKey:@"transform.rotation.z"];
    
    [self performSelector:@selector(done) withObject:nil afterDelay:5.0];
}


-(void)done
{
    UIBarButtonItem *refresh = self.navigationItem.rightBarButtonItem;
    CALayer *layer = ((UIButton*)refresh.customView).imageView.layer;
    [layer removeAnimationForKey:@"transform.rotation.z"];
}

Thanks for sharing, just what I was looking for.

This seems straightforward but I can't seem to get this to work - does anyone have any sample code or a sample project I could look at? Here's what I've put in viewDidLoad:

UIButton *refreshButton = [UIButton buttonWithType:UIButtonTypeCustom];
UIImage *refreshButtonImage = [UIImage imageNamed:@"BarButtonIconHelp"];
[refreshButton setFrame:CGRectMake(0, 0, 20, 20)];
[refreshButton setBackgroundImage:refreshButtonImage forState:UIControlStateNormal];
[refreshButton addTarget:self action:@selector(tap:) forControlEvents:UIControlEventTouchUpInside];
UIBarButtonItem *refreshBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:refreshButton];
self.navigationItem.rightBarButtonItem = refreshBarButtonItem;

I can confirm that the tap method is being called, but no animation is occurring! (Sorry if this is obvious, I'm a beginner.)