iphone - Animate UIButton state change

Question

I'm using a UIButton with images for normal and highlighted states. They work as expected but I want to have some fading/merging transition and not just a sudden swap.

How can I do that?

Answer 1

This can be done using transition animation of a UIView. It does not matter the isHighlighted property is not animatable, because it transitions the whole view.

Swift 3

UIView.transition(with: button,
                  duration: 4.0,
                  options: .transitionCrossDissolve,
                  animations: { button.isHighlighted = true },
                  completion: nil)

Objective-C

[UIView transitionWithView:button
                  duration:4.0
                   options:UIViewAnimationOptionTransitionCrossDissolve
                animations:^{ button.highlighted = YES; }
                completion:nil];