如何获得CABasicAnimation进展？
有关 NSAnimation 开发者文档中我发现 -addProgressMark 方法。对于 CABasicAnimation 我没有发现类似的事情。
For NSAnimation in developer documentation I found the -addProgressMark method. For CABasicAnimation I didn't find anything similar.
CABasicAnimation * rotateLayer = [CABasicAnimation animationWithKeyPath:@"transform.rotation.x"];
在动画进度 rotateLayer = 50％，我想做些什么？
我该怎么做呢？
When animation progress rotateLayer = 50% I want do something...
How do I do this?
您也许可以使用的NSTimer 来做到这一点。
You could maybe use a NSTimer to do this.
在动画开始感谢 animationDidStart你可以知道： CAAnimation 的委托方法（其中 CABasicAnimation 从引用）。
You can know when the animation starts thanks to the animationDidStart: delegate method of CAAnimation (of which CABasicAnimation inherits from, reference).
你既然知道动画持续多久（您设置的动画的持续时间），你可以做任何你需要一次动画击中其持续时间的50％。
Since you know how long the animation lasts (you set the duration of the animation), you can do whatever you need once the animation hits 50% of its duration.
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