UIButton 的 IBDesignable，IBInspectable 变量为零答案

【问题标题】：IBDesignable for UIButton, IBInspectable vars are nilUIButton 的 IBDesignable，IBInspectable 变量为零
【发布时间】：2019-04-03 04:31:45
【问题描述】：

我在使用 UIButton 时遇到了一个奇怪的问题。我有以下自定义类：

import UIKit

@IBDesignable class ToggleButton: UIButton {

    @IBInspectable var state1Image: UIImage = UIImage()
    @IBInspectable var state2Image: UIImage = UIImage()
    @IBInspectable var someString: String = ""

    private var toogleOn: Bool = false {
        didSet {
            if toogleOn {
                isSelected = true
            } else {
                isSelected = false
            }
        }
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        setup()
    }


    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setup()
    }

    private func setup() {
        print("test")
        print("some string is \(someString)")
    }

    @objc func didToggleButton() {
        toogleOn = !toogleOn
    }

}

在界面生成器中，我设置了可检查变量，假设我将someString 设置为 hello。现在，当我运行应用程序并查看日志时，var 的print 是""。我也无法设置图像。它只使用默认值，不会使用我设置的新值。我在这里做错了什么？

【问题讨论】：

标签： uibutton ibdesignable ibinspectable

【解决方案1】：

试试这个：

@IBDesignable class ToggleButton: UIButton {
@IBInspectable var state1Image: UIImage = UIImage() {
    didSet {
        setup()
    }
}
@IBInspectable var state2Image: UIImage = UIImage() {
    didSet {
        setup()
    }
}
@IBInspectable var someString: String = "" {
    didSet {
        setup()
    }
}

override func prepareForInterfaceBuilder() {
    setup()
}

private func setup() {
    print("test")
    // Updating title label as someString to see the update
    self.titleLabel?.text =  someString
}

private var toogleOn: Bool = false {
    didSet {
        if toogleOn {
            isSelected = true
        } else {
            isSelected = false
        }
    }
}

override init(frame: CGRect) {
    super.init(frame: frame)
    setup()
}


required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    setup()
}

@objc func didToggleButton() {
    toogleOn = !toogleOn
}
}

【讨论】：