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私有变量值位于ios swift的CustomView中

swift4.1 uiview swift ios

vinbhai4u · 技术社区 · 7 年前

我正在尝试使用下面的代码创建一个customView

import UIKit

class CustomView: UIView {

@IBOutlet var CustomView: UIView!

private var _isSelecteda:Bool!
var isSelecteda: Bool {
    get {
        return _isSelecteda
    }
    set {
        _isSelecteda = isSelecteda
        if _isSelecteda {
            CustomView.backgroundColor = UIColor.white
            CustomView.layer.borderColor = UIColor.black.cgColor
        }
        else {
            CustomView.backgroundColor = Colors.searchGameCellBackgroundColor
            CustomView.layer.borderColor = Colors.priceLabelBorderColor?.cgColor
        }
    }
}



override init(frame: CGRect) {

    super.init(frame: frame) 
    commonInit()

}

required init?(coder aDecoder: NSCoder) {

    super.init(coder: aDecoder)
    commonInit()

}


private func commonInit() {
    Bundle.main.loadNibNamed("CustomView", owner: self, options: nil)
    addSubview(CustomView)
    self._isSelecteda = false
    CustomView.layer.cornerRadius = 3
    CustomView.layer.borderWidth = 1
    self.clipsToBounds = true
    CustomView.frame = self.bounds

}

@IBAction func btnSelectedTapped(_ sender: Any) {
    isSelecteda = !isSelecteda
}
}

当我尝试访问isSelecteda时,会调用\u isSelecteda的私有声明并重置值。我的目标是设置从ViewController中选择的isSelected的值并更改其背景色。

据我了解,情况不应该是这样。很奇怪

注意:我使用的是Xcode 9.4.1和Swift 4.1

2 回复 | 直到 7 年前

Rakesha Shastri 7 年前

为什么不用 didSet 为了这个?

didSet {
    if isSelecteda {
        CustomView.backgroundColor = UIColor.white
        CustomView.layer.borderColor = UIColor.black.cgColor
    } else {
        CustomView.backgroundColor = Colors.searchGameCellBackgroundColor
        CustomView.layer.borderColor = Colors.priceLabelBorderColor?.cgColor
    }
}

复位可能是因为变量仍然具有 oldValue 在setter中用于比较的。当调用setter中的变量时,getter得到因为 newValue 尚未设置。

注:最好按照官方命名的命名惯例 guidelines . CustomView -&燃气轮机; customView .

Rishabh 7 年前

根据我的理解,你应该这样改变设置者:

set {
    _isSelecteda = newValue
    if _isSelecteda {
        CustomView.backgroundColor = UIColor.white
        CustomView.layer.borderColor = UIColor.black.cgColor
    }
    else {
        CustomView.backgroundColor = Colors.searchGameCellBackgroundColor
        CustomView.layer.borderColor = Colors.priceLabelBorderColor?.cgColor
    }
}

新价值

当你这么做的时候:

customView.isSelecteda = false

您可以在这个问题中找到有关“oldValue”和“newValue”的更多信息: Click Here

编辑:这是正确行为的理由:

get {
    return _isSelecteda                      // false - from init call
}
set {
    _isSelecteda = isSelecteda               // isSelecteda getter called from above returning false, newValue is neglected
    if _isSelecteda {                        // returns false
        CustomView.backgroundColor = UIColor.white
        CustomView.layer.borderColor = UIColor.black.cgColor
    }
    else {
        CustomView.backgroundColor = Colors.searchGameCellBackgroundColor
        CustomView.layer.borderColor = Colors.priceLabelBorderColor?.cgColor
    }
}