When exactly do implicit animations take place in iOS?

Question

Everyone and every book claims that there are implicit animations happening in CALayer. However, every time I wanted to verify that so far, I end up with a hard-snap to the

Answer 1

Old post, but link below points to a section in the Core Animation Programming Guide that helps shed some more light on what Kevin Ballard was saying. There really needs to be a blatant note that mentions that in order to animate a UIView's underlying layer properties you need to ensure that you set the layer's delegate to an instance that will adopt the "actionForLayer:ForKey:" method and return nil. It's been found that you can also set the delegate to an instance that doesn't adopt this method and it still allows implicit animations, but this is a sloppy and confusing practice.

Core Animation - Layer Actions - Defined Search Pattern for Action Keys