Ios 将UIView的CALayer设置为圆角的动画

我正在尝试设置视图角的圆角动画。cornerRadius属性被列为可设置动画，但我似乎无法使其工作。实际上，我也无法获得任何其他属性来设置动画，但角点是我感兴趣的。这是我的代码，非常简单：

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

self.myView.layer.cornerRadius = 50.0f;

[CATransaction commit];

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伙计们，我错过了什么？角变圆了，但它是瞬间的，而不是2秒钟。

Swift 4.2/5：

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"];

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")

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")

Swift 3/4.0：

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")

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Mark所注意到的，使用

#keyPath

来描述要设置动画的属性更为简洁：

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

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看来你想得太多了。我不用CoreAnimation就可以过得去。以下是我所做的：

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

---

这个代码在哪里？在viewDidLoad中？还是会出现？或者ViewDidDisplay？这是一个按钮按下的动作。有关新的、改进的答案，请参见上文#keyPath（CALayer.cornerRadius）会稍微好一点。