Test whether a UIView is in the middle of animation

ios cocoa-touch uiview core-animation uiviewanimation
prostock picture prostock · Apr 3, 2011 · Viewed 32.3k times · Source

Is there any way to tell if a UIView is in the middle of an animation? When I print out the view object while it is moving I notice that there is an "animations" entry:

search bar should end editing: <UISearchBar: 0x2e6240; frame = (0 0; 320 88); text = ''; autoresize = W+BM; animations = { position=<CABasicAnimation: 0x6a69c40>; bounds=<CABasicAnimation: 0x6a6d4d0>; }; layer = <CALayer: 0x2e6e00>>

When the animation has stopped and I print the view, the "animations" entry is now gone:

search bar should end editing: <UISearchBar: 0x2e6240; frame = (0 0; 320 88); text = ''; autoresize = W+BM; layer = <CALayer: 0x2e6e00>>

Answer

Nick Weaver picture Nick Weaver · Apr 3, 2011

A UIView has a layer (CALayer). You can send animationKeys to it, which will give you an array of keys which identify the animations attached to the layer. I suppose that if there are any entries, the animation(s) are running. If you want to dig even deeper have a look at the CAMediaTiming protocol which CALayer adopts. It does some more information on the current animation.

Important: If you add an animation with a nil key ([layer addAnimation:animation forKey:nil]), animationKeys returns nil.

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