ios - 快速更新类(class)

我正在寻找解决问题的方法。我有一个为我创建 UIButton 的类:

class MenuButton: UIButton {

    var x: CGFloat
    var y: CGFloat
    var width: CGFloat
    var height: CGFloat

    required init(parent: UIView = UIView(), x: CGFloat = 0, y: CGFloat = 0, width: CGFloat = 40, height: CGFloat = 40) {

        self.x = x
        self.y = y
        self.width = width
        self.height = height

        super.init(frame: .zero)

        frame = CGRect(x: x, y: y, width: width, height: height)
        backgroundColor = global.labelColor
        setTitleColor(#colorLiteral(red: 0, green: 0, blue: 0, alpha: 1), for: .normal)
        layer.cornerRadius = self.frame.height / 2

        if x < 0 {
            frame = CGRect(x: superview?.frame.width ?? 0 - abs(x) - frame.width, y: frame.minY, width: frame.width, height: frame.height)
        }

        if y < 0 {
            frame = CGRect(x: frame.minX, y: superview?.frame.height ?? 0 - abs(y) - frame.height, width: frame.width, height: frame.height)
        }
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder has not been implemented")
    }
}

然后我添加一个分配给这个类的常量:

let pauseButton = MenuButton()

这工作正常，按钮显示在场景中，所有内容均为默认设置。现在我想在 viewDidLoad() 中添加这些东西(我添加了 subview 以在类中访问它):

view.addSubview(pauseButton)
pauseButton.x = -20
pauseButton.y = 20
pauseButton.width = 40
pauseButton.height = 40

这不会更新我在 init() 中指定的内容。如何再次调用 init(无需再次执行 pauseButton = MenuButton())还是可以使用类似 update() 的方法？

感谢您的帮助；)

---

Best Answer-推荐答案

您实际上可以在初始化程序中传递这些值，如下所示，

let pauseButton = MenuButton(parent: view, x: -20, y: 20, width: 40, height: 40)

如果您想在更改任何这些属性时立即更新按钮，则可以使用 didSet 回调来设置 frame，如下所示，

class MenuButton: UIButton {

    var x: CGFloat {
        didSet {
            self.updateFrame()
        }
    }

    var y: CGFloat  {
        didSet {
            self.updateFrame()
        }
    }

    var width: CGFloat  {
        didSet {
            self.updateFrame()
        }
    }

    var height: CGFloat  {
        didSet {
            self.updateFrame()
        }
    }

    private func updateFrame() {
        frame = CGRect(x: x, y: y, width: width, height: height)
    }

    required init(parent: UIView = UIView(), x: CGFloat = 0, y: CGFloat = 0, width: CGFloat = 40, height: CGFloat = 40) {

        self.x = x
        self.y = y
        self.width = width
        self.height = height

        super.init(frame: .zero)

        frame = CGRect(x: x, y: y, width: width, height: height)
        backgroundColor = .green
        setTitleColor(#colorLiteral(red: 0, green: 0, blue: 0, alpha: 1), for: .normal)
        layer.cornerRadius = self.frame.height / 2

        if x < 0 {
            frame = CGRect(x: superview?.frame.width ?? 0 - abs(x) - frame.width, y: frame.minY, width: frame.width, height: frame.height)
        }

        if y < 0 {
            frame = CGRect(x: frame.minX, y: superview?.frame.height ?? 0 - abs(y) - frame.height, width: frame.width, height: frame.height)
        }
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder has not been implemented")
    }
}

关于ios - 快速更新类(class)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/52966532/