将 UIView 的 CALayer 动画化为圆角

Question

我正在尝试为我的视图的拐角设置动画。 cornerRadius 属性被列为可动画，但我似乎无法让它工作。实际上，我也无法获得任何其他属性来设置动画，但我感兴趣的是角。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];

伙计们，我在这里缺少什么？边角变成圆角，但它是瞬时的，而不是需要 2 秒。

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"];

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 Mark 所注意到的，使用 #keyPath 更简洁描述要动画的属性：

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

Answer 3

看来你想多了。我在不使用 CoreAnimation 的情况下也能过得去。这就是我所做的：

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