macOS 14下NSTextField富文本链接前景色设置失效求助

在macOS中，当NSTextField开启isSelectable或allowsEditingTextAttributes时，系统会自动用默认的NSColor.linkColor覆盖你设置的链接前景色，这就是问题的根源。

以下是两种可行的解决思路：

方法一：自定义NSTextFieldCell（推荐） #

通过重写文本字段单元格的绘制方法，强制应用自定义的链接颜色，同时保留系统链接的原生交互行为：

class CustomLinkTextFieldCell: NSTextFieldCell {
    override func drawInterior(withFrame cellFrame: NSRect, in controlView: NSView) {
        guard let attrString = attributedStringValue.mutableCopy() as? NSMutableAttributedString else {
            super.drawInterior(withFrame: cellFrame, in: controlView)
            return
        }
        
        // 遍历所有链接属性，强制设置自定义颜色
        attrString.enumerateAttribute(.link, in: NSRange(location: 0, length: attrString.length)) { _, range, _ in
            attrString.addAttribute(.foregroundColor, value: NSColor.red, range: range)
        }
        
        attributedStringValue = attrString
        super.drawInterior(withFrame: cellFrame, in: controlView)
    }
}

给你的NSTextField绑定自定义单元格并设置富文本：

textField.cell = CustomLinkTextFieldCell()
textField.allowsEditingTextAttributes = true
textField.isSelectable = true

let urlText = "https://google.com"
let attributedString = NSMutableAttributedString(string: urlText)
let range = NSMakeRange(0, urlText.count)
attributedString.addAttribute(.link, value: urlText, range: range)

textField.attributedStringValue = attributedString

方法二：手动处理链接点击（无系统样式干扰） #

如果不需要系统默认的链接选中样式，可以关闭系统选择逻辑，手动设置颜色并处理点击事件：

textField.allowsEditingTextAttributes = true
textField.isSelectable = false // 关闭系统选择样式，避免颜色覆盖
textField.isEditable = false

let urlText = "https://google.com"
let attributedString = NSMutableAttributedString(string: urlText)
let range = NSMakeRange(0, urlText.count)

attributedString.addAttribute(.link, value: urlText, range: range)
attributedString.addAttribute(.foregroundColor, value: NSColor.red, range: range)
// 可选：添加下划线模拟标准链接样式
attributedString.addAttribute(.underlineStyle, value: NSUnderlineStyle.single.rawValue, range: range)

textField.attributedStringValue = attributedString

// 添加点击手势识别器
let tapGesture = NSClickGestureRecognizer(target: self, action: #selector(handleLinkTap(_:)))
textField.addGestureRecognizer(tapGesture)

实现点击处理方法：

@objc func handleLinkTap(_ gesture: NSClickGestureRecognizer) {
    guard let textField = gesture.view as? NSTextField,
          let attrString = textField.attributedStringValue else { return }
    
    let location = gesture.location(in: textField)
    let layoutManager = NSLayoutManager()
    let textContainer = NSTextContainer(size: textField.bounds.size)
    let textStorage = NSTextStorage(attributedString: attrString)
    
    layoutManager.addTextContainer(textContainer)
    textStorage.addLayoutManager(layoutManager)
    
    textContainer.lineFragmentPadding = 0
    textContainer.maximumNumberOfLines = 1
    textContainer.lineBreakMode = textField.lineBreakMode
    
    let characterIndex = layoutManager.characterIndex(for: location, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
    
    if characterIndex < attrString.length {
        attrString.enumerateAttribute(.link, in: NSRange(location: characterIndex, length: 1)) { value, _, _ in
            if let urlString = value as? String, let url = URL(string: urlString) {
                NSWorkspace.shared.open(url)
            }
        }
    }
}

内容的提问来源于stack exchange，提问作者Ross Stepaniak