iOS中UIView實現(xiàn)不同方向的導角

更新時間：2018年05月15日 11:49:13 作者：東引甌越

這篇文章主要給大家介紹了關于iOS中UIView實現(xiàn)不同方向的導角的相關資料，文中通過示例代碼介紹的非常詳細，對大家學習或使用iOS具有一定的參考學習價值，需要的朋友們下面隨著小編來一起學習學習吧

前言

開發(fā)中總因為一些比較蛋疼的導角問題而困擾著我們,尤其是我們要給一個UIView導角成左上、左下。。。

這種需求很值得用代碼實現(xiàn)一下, 今天突然在AppCode找到了一篇好文章.于是有了下文

通常導角

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

這兩行代碼是全方向導角

如果像要搞成不同方向的話可以用iOS11 新的API和 iOS11以前的CAShapeLayer畫貝賽爾曲線來解決

首先我們要創(chuàng)建一個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 以后蘋果提供了一個UIView的屬性叫maskedCorners用于CALayer的動畫相關.

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 }
}

下面我說一下

layerMinXMinYCorner 底部右側的圓角 -> 右下角
layerMaxXMinYCorner 頂部右側的圓角 -> 右上角
layerMinXMaxYCorner 底部左側的圓角 -> 左下角
layerMinXMinYCorner 頂部左側的圓角 -> 左上角

一般我們都為UIView寫個 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
  }
  
 }
}

這里區(qū)分了iOS11之前和之后的兩種搞法.

之前的話我們都是用一個貝塞爾曲線畫path.然后創(chuàng)建CAShapeLayer 給self.layer.mask做一種透明的遮罩來解決不同方向導角問題.

添加動畫效果的導角

我們在原ViewDidLoad()方法里面加個手勢.

并寫好觸發(fā)的事件, 完整的代碼如下

import UIKit
class 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
  }
 }
}

這里主要強調一下動畫的新API

iOS10之后U增加一個新的動畫效果API

UIViewPropertyAnimator(duration: 0.4, curve: .easeInOut) {
//這里寫相關View的操作代碼 。。。eg:下面代碼
    self.cardView.roundCorners(cornerRadius: targetRadius)
    }.startAnimation()

iOS之前可以通過古老的API來實現(xiàn)

UIView.animate(withDuration: 1.0, delay: 0.0, options: .curveEaseInOut, animations: {
//這里寫相關View的操作代碼 。。。eg:下面代碼
    self.cardView.roundCorners(cornerRadius: targetRadius)
   }, completion: nil)

最終的效果