将UIView的CALayer动画化以实现圆角

Question

我想要对我的视图的圆角进行动画处理。cornerRadius属性被列为可动画处理的，但是我似乎无法使其工作。实际上，我也无法使任何其他属性进行动画处理，但是我对圆角比较感兴趣。以下是我的代码，非常简单：

[CATransaction begin];
[CATransaction setValue: [NSNumber numberWithFloat: 2.0f] forKey:kCATransactionAnimationDuration];

self.myView.layer.cornerRadius = 50.0f;

[CATransaction commit];

我在这里错过了什么吗？角落变得圆润，但瞬间完成而不是需要2秒钟。

- Micah Hainline

Answer 1

CABasicAnimation *anim1 = [CABasicAnimation animationWithKeyPath:@"cornerRadius"];
anim1.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
anim1.fromValue = [NSNumber numberWithFloat:0.0f];
anim1.toValue = [NSNumber numberWithFloat:50.0f];
anim1.duration = 2.0;
[self.myView.layer addAnimation:anim1 forKey:@"cornerRadius"];

- picciano

---

这段代码位于哪里？是在viewDidLoad中吗？还是在viewWillAppear中？或者是在viewDidAppear中？ - picciano

这是按钮按下的操作。 - Micah Hainline

请参见上面的新、改进答案。 - picciano

Answer 2

Swift 4.2/5:

let anim1 = CABasicAnimation(keyPath: "cornerRadius")
anim1.timingFunction = CAMediaTimingFunction(name: CAMediaTimingFunctionName.linear)
anim1.fromValue = 0
anim1.toValue = 50
anim1.duration = 2.0
layer.add(anim1, forKey: "cornerRadius")

Swift 3/4.0:

let anim1 = CABasicAnimation(keyPath: "cornerRadius")
anim1.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionLinear)
anim1.fromValue = 0
anim1.toValue = 50
anim1.duration = 2.0
myView.layer.add(anim1, forKey: "cornerRadius")

更新：

正如马克所指出的那样，使用#keyPath来描述要进行动画的属性更加简洁：

let anim1 = CABasicAnimation(keyPath: #keyPath(CALayer.cornerRadius))

- KlimczakM

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#keyPath(CALayer.cornerRadius) 会稍微好一些。 - Mark Bridges

Answer 3

看起来你想太多了。我能够在不使用CoreAnimation的情况下完成任务。这是我所做的：

UIView.animate(withDuration: animationDuration) {
    self.myView.layer.cornerRadius = 10.0
}

- toddg