SwiftUI含链接与换行文本的截断异常问题求助

这确实是SwiftUI在处理带link属性的多行富文本截断时的渲染Bug，不少开发者都遇到过类似情况——当文本包含换行符且设置了lineLimit时，带链接属性的文本会丢失尾部省略号，无链接或无换行符时则正常。

下面是几个可行的解决办法：

1. 用UITextView封装替代SwiftUI Text #

SwiftUI的Text组件在富文本截断+链接的场景下兼容性不佳，改用UIKit的UITextView封装成SwiftUI组件是最稳妥的方案，UITextView对带链接的文本截断逻辑更成熟：

struct LinkedTextView: UIViewRepresentable {
    let attributedText: NSAttributedString
    let lineLimit: Int
    let onLinkTap: (URL) -> Void
    
    func makeUIView(context: Context) -> UITextView {
        let textView = UITextView()
        textView.isEditable = false
        textView.isScrollEnabled = false
        textView.textContainer.maximumNumberOfLines = lineLimit
        textView.textContainer.lineBreakMode = .byTruncatingTail
        textView.delegate = context.coordinator
        return textView
    }
    
    func updateUIView(_ uiView: UITextView, context: Context) {
        uiView.attributedText = attributedText
    }
    
    func makeCoordinator() -> Coordinator {
        Coordinator(onLinkTap: onLinkTap)
    }
    
    class Coordinator: NSObject, UITextViewDelegate {
        let onLinkTap: (URL) -> Void
        
        init(onLinkTap: @escaping (URL) -> Void) {
            self.onLinkTap = onLinkTap
        }
        
        func textView(_ textView: UITextView, shouldInteractWith URL: URL, in characterRange: NSRange, interaction: UITextItemInteraction) -> Bool {
            onLinkTap(URL)
            return false
        }
    }
}

// 使用示例
struct ContentView: View {
    let attributedText: NSAttributedString = {
        let string = "这是一段带换行\n的长文本，后面跟着一个链接：示例链接，需要被截断显示"
        let attributedString = NSMutableAttributedString(string: string)
        let linkRange = (string as NSString).range(of: "示例链接")
        attributedString.addAttribute(.link, value: URL(string: "https://example.com")!, range: linkRange)
        return attributedString
    }()
    
    var body: some View {
        LinkedTextView(attributedText: attributedText, lineLimit: 2) { url in
            print("点击了链接：\(url)")
        }
        .frame(maxWidth: .infinity, alignment: .leading)
    }
}

2. 手动计算截断位置并拼接省略号 #

如果不想引入UIKit依赖，可以用TextKit手动计算文本在指定宽度下的可显示范围，截断后手动添加省略号，再给处理后的文本添加链接属性（注意不要给省略号加链接）：

func truncatedAttributedText(for text: NSAttributedString, width: CGFloat, lineLimit: Int) -> NSAttributedString {
    let textContainer = NSTextContainer(size: CGSize(width: width, height: .greatestFiniteMagnitude))
    textContainer.maximumNumberOfLines = lineLimit
    textContainer.lineBreakMode = .byTruncatingTail
    
    let layoutManager = NSLayoutManager()
    layoutManager.addTextContainer(textContainer)
    
    let storage = NSTextStorage(attributedString: text)
    storage.addLayoutManager(layoutManager)
    
    layoutManager.glyphRange(for: textContainer)
    let visibleRange = layoutManager.characterRange(forGlyphRange: NSRange(location: 0, length: layoutManager.numberOfGlyphs), actualGlyphRange: nil)
    
    if visibleRange.length < text.length {
        // 截断后保留到前一个字符，避免截断到链接中间
        let safeRange = NSRange(location: 0, length: visibleRange.length - 1)
        let truncatedText = text.attributedSubstring(from: safeRange)
        let ellipsis = NSAttributedString(string: "...")
        let result = NSMutableAttributedString(attributedString: truncatedText)
        result.append(ellipsis)
        return result
    } else {
        return text
    }
}

// 使用示例
struct ContentView: View {
    let originalText: NSAttributedString = {
        let string = "带换行\n的长文本，链接在这里：测试链接，后面还有很多内容需要被截断..."
        let attrString = NSMutableAttributedString(string: string)
        let linkRange = (string as NSString).range(of: "测试链接")
        attrString.addAttribute(.link, value: URL(string: "https://test.com")!, range: linkRange)
        return attrString
    }()
    
    @State private var truncatedText: NSAttributedString?
    
    var body: some View {
        Text(truncatedText ?? originalText)
            .onAppear {
                // 这里的宽度可以根据实际布局调整，比如用UIScreen.main.bounds.width - 40
                truncatedText = truncatedAttributedText(for: originalText, width: 300, lineLimit: 2)
            }
            .lineLimit(2)
    }
}

3. 临时Workaround：替换换行符（业务允许的话） #

如果文本中的换行符不是必须保留的格式，可以尝试把所有换行符替换成空格，这样SwiftUI的Text组件就能正常显示省略号了：

let originalString = "带换行\n的长文本..."
let noNewlineString = originalString.replacingOccurrences(of: "\n", with: " ")
// 再给noNewlineString添加链接属性

内容的提问来源于stack exchange，提问作者wilybear