使用核心动画更改cornerRadius

Question

我正在尝试以以下方式更改按钮（OpenNoteVisible.layer）的圆角半径：

CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"cornerRadius"];
animation.timingFunction = [CAMediaTimingFunction     functionWithName:kCAMediaTimingFunctionLinear];
animation.fromValue = [NSNumber numberWithFloat:10.0f];
animation.toValue = [NSNumber numberWithFloat:0.0f];
animation.duration = 1.0;
[animation.layer setCornerRadius:140.0];
[OpenNoteVisible.layer addAnimation:animation forKey:@"cornerRadius"];

但是这段代码在[animation.layer setCornerRadius:140.0];这一行报错，我不明白为什么。我已经导入了Quartz core框架。

- user2014474

---

你可以为按钮设置圆角。因此请使用按钮对象。 - SRI

Answer 1

你正在为动画对象的图层属性设置圆角半径；但是，这个动画对象没有图层属性。

你需要在你要动画的东西的图层上设置圆角半径，此处为OpenNoteVisible。你还需要确保动画对象的toValue与你在图层上设置的值相匹配，否则会出现奇怪的动画效果。

你的代码应该改为：

CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"cornerRadius"];
animation.timingFunction = [CAMediaTimingFunction     functionWithName:kCAMediaTimingFunctionLinear];
animation.fromValue = [NSNumber numberWithFloat:10.0f];
animation.toValue = [NSNumber numberWithFloat:140.0f];
animation.duration = 1.0;
[OpenNoteVisible.layer setCornerRadius:140.0];
[OpenNoteVisible.layer addAnimation:animation forKey:@"cornerRadius"];

- WDUK

Answer 2

Swift 4 的解决方案如下：

import UIKit
import PlaygroundSupport

let view = UIView(frame: CGRect(x: 0, y: 0, width: 400, height: 400))
view.backgroundColor = #colorLiteral(red: 1, green: 0.5763723254, blue: 0, alpha: 1)
PlaygroundPage.current.liveView = view

UIView.animate(withDuration: 2.5, animations: {
    view.layer.cornerRadius = 40
}, completion: { _ in
    UIView.animate(withDuration: 0.5, animations: {
        view.layer.cornerRadius = 0
    })
})

- Durul Dalkanat