使用 IBDesignable UILabel 类时出现的奇怪问题

问题描述

当我尝试使用我设计的自定义 UILabel 时，我遇到了一个奇怪的问题.该视图在故事板中可见，并且可以很好地处理属性.现在我所做的是在我的 Designable 类中我设置了一个名为 isError 的属性，当设置时，我需要在文本的开头附加一个 *.

I am facing a weird issue when I try to use the custom UILabel that I have designed. The view is visible in the storyboard and its working fine with properties. Now What I have done is in my Designable class i have set a property called isError which when set, I need to append an * at the start of my text.

但是一旦在我的代码中我这样做了，我的可设计属性就没有被使用，标签也没有正确显示在设备上，它采用 UILabel 的默认属性，而不在文本中添加 *.不知道我哪里出错了.

But as soon as in my code I do that, My Designable properties are not used and the Label is not correctly shown on the device and it takes the default properties of UILabel without adding * to the text. Not sure where I am going wrong.

自定义标签代码

@IBDesignable class KGIBDesignableLabel: UILabel {

    @IBInspectable var verticalPad: CGFloat = 0
    @IBInspectable var horizontalPad: CGFloat = 0
    var isError: Bool = false{
        didSet {
            setup()
        }
    }

    override func awakeFromNib() {
        super.awakeFromNib()
        setup()
    }
    override func layoutSubviews() {
        super.layoutSubviews()
        setup()
    }
    override func prepareForInterfaceBuilder() {
        super.prepareForInterfaceBuilder()
        setup()
    }


    func setup(){
        if isError{
            text="*"+text!;
            textColor = UIColor.KGColorPalette.errorMessageColor
        }else{
            textColor = UIColor.KGColorPalette.textEntryLabelColor
            text=text!;
        }

        font = UIFont(name: "Helvetica", size: 14)
        clipsToBounds = true
        textAlignment = .center
        numberOfLines = 0
        lineBreakMode = NSLineBreakMode.byWordWrapping

        sizeToFit()
    }

    override var intrinsicContentSize: CGSize {
        let superSize = super.intrinsicContentSize
        let newWidth = superSize.width + superSize.height + (2 * horizontalPad)
        let newHeight = superSize.height + (2 * verticalPad)
        let newSize = CGSize(width: newWidth, height: newHeight)
        return newSize
    }
}

VC 中的访问代码

class ViewController: UIViewController {
    @IBOutlet weak var labelCustom: KGIBDesignableLabel!



    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        labelCustom.isError=true
        // After adding this^ line it takes default UILabel properties
    }

推荐答案

First Mistake 在您的 layoutSubview 方法中调用 setup 导致连续调用从 setup 到 layoutSubview 因为您正在修改 setup 中导致 layoutSubview 被调用的内容

First Mistake calling setup in your layoutSubview method cause a consecutive calling from setup to layoutSubview because you are modifying things in the setup that cause layoutSubview is called

修复从 layoutSubviews()

第二个错误在您的 setup 中调用 sizeToFit() 将文本的大小调整为当前大小，然后再计算您的内在内容大小

Second Mistake calling sizeToFit() in your setup adjust the size of your text to the current size before calculate your intrinsic content size

修复从您的设置

第三个错误你设置为 width label.intrinsicSize.width + label.intrinsicSize.height + (2 * horizo​​ntalPad) 是很明显那里的高度是错误的

Third Mistake you were setting as width the label.intrinsicSize.width + label.intrinsicSize.height + (2 * horizontalPad) is obvious that height is wrong there

Fix 将这一行 let newWidth = superSize.width + superSize.height + (2 * horizo​​ntalPad) 替换为这一行 `let newWidth = superSize.width + (2*horizo​​ntalPad)

Fix replace this line let newWidth = superSize.width + superSize.height + (2 * horizontalPad) by this one `let newWidth = superSize.width + (2 * horizontalPad)

您的代码修改和工作

@IBDesignable class KGIBDesignableLabel: UILabel {

    @IBInspectable var verticalPad: CGFloat = 0
    @IBInspectable var horizontalPad: CGFloat = 0
    var isError: Bool = false{
        didSet {
            setup()
        }
    }

    override func awakeFromNib() {
        super.awakeFromNib()
        setup()
    }

    override func prepareForInterfaceBuilder() {
        super.prepareForInterfaceBuilder()
        setup()
    }


    func setup(){
        if isError{
            text="*"+text!;
            textColor = UIColor.red
        }else{
            textColor = UIColor.black
            text=text!;
        }

        font = UIFont(name: "Helvetica", size: 14)
        clipsToBounds = true
        textAlignment = .center
        numberOfLines = 0
        lineBreakMode = NSLineBreakMode.byWordWrapping
    }

    override var intrinsicContentSize: CGSize {
        let superSize = super.intrinsicContentSize
        let newWidth = superSize.width + (2 * horizontalPad)
        let newHeight = superSize.height + (2 * verticalPad)
        let newSize = CGSize(width: newWidth, height: newHeight)
        return newSize
    }
}

这是使用 10 和 10 作为垂直和水平填充值的外观

this is how it looks with 10 and 10 as values por vertical and horizontal padding

希望能帮到你

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