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自定义枚举案例的UIView扩展中的新属性

swift ios

cs4alhaider Andrei G. · 技术社区 · 6 年前

在这里,我创建了一个小枚举来保存我的所有动画案例:

enum ViewAnimation {
    case changeColor(to: UIColor, duration: TimeInterval)
    case hideView(duruation: TimeInterval)
}

在这里,我想为UIView创建一个属性:

extension UIView {


var animate: ViewAnimation {
    get {
        return .changeColor(to: .red, duration: 1) // actually I don't know what to add in the getter !
    }
    set {
        switch self.animate {
        case .changeColor(let newColor, let duration):
            UIView.animate(withDuration: duration) {
                self.backgroundColor = newColor
            }
        case .hideView(let duration):
            UIView.animate(withDuration: duration) {
                self.alpha = 0
                self.isHidden = true
            }
        }
    }
}

}

这是我的课:

import UIKit

class ViewController: UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()

    let smallView = UIView(frame: CGRect(x: 0, y: 0, width: 200, height: 200))
    view.addSubview(smallView)
    smallView.backgroundColor = .red
    smallView.center = view.center

    DispatchQueue.main.asyncAfter(deadline: .now() + 2) {
        smallView.animate = .changeColor(to: .blue, duration: 3)
    }
}
}

问题是当我打电话 smallView.animate = .changeColor(to: .blue, duration: 3) 没什么变化!

知道为什么没用吗?

3 回复 | 直到 6 年前

Rico Crescenzio 6 年前

为什么要在扩展中创建属性?你甚至不需要干杯。嗯,最好是创造一种方法。

extension UIView {
    func animate(animation: ViewAnimation) {
        switch animation {
        case .changeColor(let newColor, let duration):
            UIView.animate(withDuration: duration) {
                self.backgroundColor = newColor
            }
        case .hideView(let duration):
            UIView.animate(withDuration: duration) {
                self.alpha = 0
                self.isHidden = true
            }
        }
    }
}

并称之为 smallView.animate(animation: .changeColor(to: .blue, duration: 3))

switch self.animate 因为它会叫“盖特”。试着做 switch newValue set 有一个隐式局部变量 newValue 这是分配的当前值。

AppleCiderGuy 6 年前

您正在检查开关盒中的旧值。你需要这样做:

switch newValue {
    case .changeColor(let newColor, let duration):
        UIView.animate(withDuration: duration) {
            self.backgroundColor = newColor
        }
    case .hideView(let duration):
        UIView.animate(withDuration: duration) {
            self.alpha = 0
            self.isHidden = true
        }
    }

newValue 如果实现如下设置,则为默认值 set{ 或者你可以这样做:

set(abc){
  switch abc {

Mocha 6 年前

我相信开关实际上是在调用getter,因此总是将背景设置为红色。

var helpme: Int {
    get {
        return 1
    }
    set {
        switch helpme {
        default:
            print(helpme)
        }
    }
}

func testme() {
    helpme = 20
    print(helpme)
}

output:
1
1

    switch self.animate { //  calls the getter which returns red
    case .changeColor(let newColor, let duration):
        UIView.animate(withDuration: duration) {
            self.backgroundColor = newColor
        }
    case .hideView(let duration):
        UIView.animate(withDuration: duration) {
            self.alpha = 0
            self.isHidden = true
        }
    }

我认为一个房产对于你想做的事情来说太有限了。

class AnimatingView: UIView {
  var animationType: AnimationType?
}


enum AnimationType {
  case changingColor
  case hidingView
}

func changeColor() {
  animationType = .changingColor
  // change color
}