How do you change UIButton image alpha on disabled state?

Question

I have a UIButton with an image and on its disabled state, this image should have .3 alpha.

UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
UIIm         


        

Answer 1

Subclassing UIButton and extending the setEnabled: method seems to work:

- (void) setEnabled:(BOOL)enabled {    
    [super setEnabled:enabled];
    if (enabled) {
        self.imageView.alpha = 1;
    } else {
        self.imageView.alpha = .25;
    }
}

I haven't tested it thoroughly, but did find the value resets if the screen is rotated. Adding the same code to the setFrame: method fixes that, but I'm not sure if there are other situations where this value is changed.