前言

开发中总因为一些比较蛋疼的导角问题而困扰着我们,尤其是我们要给一个UIView导角成 左上 、左下。。。

这种需求很值得用代码实现一下, 今天突然在AppCode找到了一篇好文章.于是有了下文

通常导角

self.view.cornerRadius = 20.0self.view.clipToBounds = true

这两行代码是全方向导角

如果像要搞成不同方向的话可以用iOS11 新的API和 iOS11以前的CAShapeLayer画贝赛尔曲线来解决

首先我们要创建一个UIView

class ViewController: UIViewController { var cardView: UIView! override func viewDidLoad() { super.viewDidLoad() cardView = UIView() view.addSubview(cardView)cardView.translatesAutoresizingMaskIntoConstraints = false //把View居中 cardView.widthAnchor.constraint(equalToConstant: 200).isActive = true cardView.heightAnchor.constraint(equalToConstant: 200).isActive = true cardView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true cardView.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true cardView.backgroundColor = UIColor(red: 1.0, green: 0.784, blue: 0.2, alpha: 1) }}

iOS11 以后苹果提供了一个UIView的属性叫maskedCorners用于CALayer的动画相关.

public struct CACornerMask : OptionSet { public init(rawValue: UInt) public static var layerMinXMinYCorner: CACornerMask { get } public static var layerMaxXMinYCorner: CACornerMask { get } public static var layerMinXMaxYCorner: CACornerMask { get } public static var layerMaxXMaxYCorner: CACornerMask { get }}

下面我说一下

• layerMinXMinYCorner 底部右侧 的圆角 -> 右下角
• layerMaxXMinYCorner 顶部右侧 的圆角 -> 右上角
• layerMinXMaxYCorner 底部左侧 的圆角 -> 左下角
• layerMinXMinYCorner 顶部左侧 的圆角 -> 左上角

一般我们都为UIView写个 extension

extension UIView { func roundCorners(cornerRadius: Double) { self.layer.cornerRadius = CGFloat(cornerRadius) self.clipsToBounds = true if #available(iOS 11.0, *) { self.layer.maskedCorners = [.layerMinXMinYCorner, .layerMaxXMinYCorner] } else { let path = UIBezierPath(roundedRect: self.bounds, byRoundingCorners: [.topLeft, .topRight], cornerRadii: CGSize(width: cornerRadius, height: cornerRadius)) let maskLayer = CAShapeLayer() maskLayer.frame = self.bounds maskLayer.path = path.cgPath self.layer.mask = maskLayer } }}

这里区分了iOS11之前和之后的两种搞法.

之前的话我们都是用一个贝塞尔曲线画path.然后创建CAShapeLayer 给self.layer.mask做一种透明的遮罩来解决不同方向导角问题.

添加动画效果的导角

我们在原ViewDidLoad()方法里面加个手势.

并写好触发的事件, 完整的代码如下

import UIKitclass ViewController: UIViewController { var cardView: UIView! override func viewDidLoad() { super.viewDidLoad() cardView = UIView() view.addSubview(cardView)cardView.translatesAutoresizingMaskIntoConstraints = false cardView.widthAnchor.constraint(equalToConstant: 200).isActive = true cardView.heightAnchor.constraint(equalToConstant: 200).isActive = true cardView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true cardView.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true cardView.backgroundColor = UIColor(red: 1.0, green: 0.784, blue: 0.2, alpha: 1) let tapRecognizer = UITapGestureRecognizer(target: self, action: #selector(animateCornerChange(recognizer:))) cardView.addGestureRecognizer(tapRecognizer) } @objc func animateCornerChange(recognizer: UITapGestureRecognizer) { let targetRadius: Double = (cardView.layer.cornerRadius == 0.0) ? 100.0:0.0 if #available(iOS 10.0, *) { UIViewPropertyAnimator(duration: 0.4, curve: .easeInOut) { self.cardView.roundCorners(cornerRadius: targetRadius) }.startAnimation() } else { UIView.animate(withDuration: 1.0, delay: 0.0, options: .curveEaseInOut, animations: { }, completion: nil) } }}extension UIView { func roundCorners(cornerRadius: Double) { self.layer.cornerRadius = CGFloat(cornerRadius) self.clipsToBounds = true if #available(iOS 11.0, *) { self.layer.maskedCorners = [.layerMinXMinYCorner, .layerMaxXMinYCorner] } else { let path = UIBezierPath(roundedRect: self.bounds, byRoundingCorners: [.topLeft, .topRight], cornerRadii: CGSize(width: cornerRadius, height: cornerRadius)) let maskLayer = CAShapeLayer() maskLayer.frame = self.bounds maskLayer.path = path.cgPath self.layer.mask = maskLayer } }}

这里主要强调一下动画的新API

iOS10之后U增加一个新的动画效果API

UIViewPropertyAnimator(duration: 0.4, curve: .easeInOut) {//这里写相关View的操作代码 。。。eg:下面代码 self.cardView.roundCorners(cornerRadius: targetRadius) }.startAnimation()

iOS之前可以通过古老的API来实现

UIView.animate(withDuration: 1.0, delay: 0.0, options: .curveEaseInOut, animations: {//这里写相关View的操作代码 。。。eg:下面代码 self.cardView.roundCorners(cornerRadius: targetRadius) }, completion: nil)

最终的效果

总结

iOS一些简单的动画导角比较常用所以记录下来,以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作具有一定的参考学习价值，如果有疑问大家可以留言交流，谢谢大家对的支持。

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