swift - 代码 9 : Cannot convert value of type '[String : Any]' to expected argument type '[NSAttributedStringKey : Any]?'

Question

我有一个自定义的 UIOutlineLabel 类，它在标签内的文本周围绘制轮廓。自更新到 Swift 4 后，我收到以下错误:
无法将类型“[String:Any]”的值转换为预期的参数类型“[NSAttributedStringKey:Any]？”。

我尝试将 strokeTextAttributes 更改为:

as! [NSAttributedStringKey : Any] 

但这会导致运行时错误。

还有“UIOutlineLabel setOutlineWidth 已弃用并将在 Swift 4 中删除”和“UIOutlineLabel setOutlineColor 已弃用并将在 Swift 4 中删除”的 Swift 语言运行时警告。

旧代码:

import UIKit

class UIOutlineLabel: UILabel {

    /*
    // Only override drawRect: if you perform custom drawing.
    // An empty implementation adversely affects performance during animation.
    override func drawRect(rect: CGRect) {
        // Drawing code
    }
    */
    var outlineWidth: CGFloat = 1
    var outlineColor: UIColor = UIColor.white

    override func drawText(in rect: CGRect) {

        let strokeTextAttributes = [
            NSAttributedStringKey.strokeColor.rawValue : outlineColor,
            NSAttributedStringKey.strokeWidth : -1 * outlineWidth,
        ] as! [String : Any]

        self.attributedText = NSAttributedString(string: self.text ?? "", attributes: strokeTextAttributes)
        super.drawText(in: rect)
    }
}

Answer 1

我认为你应该使用:

override func drawText(in rect: CGRect) {
    let strokeTextAtrributes: [NSAttributedStringKey : Any] = [
        NSAttributedStringKey.strokeColor : outlineColor,
        NSAttributedStringKey.strokeWidth : -1 * outlineWidth,
    ]
    self.attributedText = NSAttributedString(string: self.text ?? "", attributes: strokeTextAttributes)
    super.drawText(in: rect)
}

因为 attributes 参数需要一个 [NSAttributedStringKey : Any]? 类型