如何在SwiftUI中实现Label文本的首行缩进？

方法一：SwiftUI 原生实现（iOS 15+） #

利用Text的paragraphStyle修饰符直接设置首行缩进，代码如下：

ZStack {
    Image.book
        .resizable()
        .aspectRatio(contentMode: .fit)
        .frame(width: 12, height: 10)
    Text(verbatim: entry.verse)
        .font(.openSansRegular(withSize: 11))
        .multilineTextAlignment(.leading)
        .paragraphStyle {
            let style = NSMutableParagraphStyle()
            // 调整首行缩进值，这里设为16pt，按需修改
            style.firstLineHeadIndent = 16
            return style
        }
}

兼容 iOS 14 及以下版本 #

如果需要适配更低系统版本，使用AttributedString构建富文本：

ZStack {
    Image.book
        .resizable()
        .aspectRatio(contentMode: .fit)
        .frame(width: 12, height: 10)
    
    if let attrText = try? AttributedString(markdown: entry.verse) {
        var mutableAttr = attrText
        let paragraphStyle = NSMutableParagraphStyle()
        paragraphStyle.firstLineHeadIndent = 16
        mutableAttr.paragraphStyle = paragraphStyle
        Text(mutableAttr)
            .font(.openSansRegular(withSize: 11))
    } else {
        Text(verbatim: entry.verse)
            .font(.openSansRegular(withSize: 11))
    }
}

方法二：封装 UILabel 复用原有逻辑 #

如果需要和你之前了解的UILabel首行缩进逻辑完全对齐，通过UIViewRepresentable封装UILabel：

// 自定义带首行缩进的Label
struct IndentedTextLabel: UIViewRepresentable {
    let text: String
    let font: UIFont
    let firstLineIndent: CGFloat
    
    func makeUIView(context: Context) -> UILabel {
        let label = UILabel()
        label.font = font
        label.numberOfLines = 0
        label.lineBreakMode = .byWordWrapping
        return label
    }
    
    func updateUIView(_ uiView: UILabel, context: Context) {
        let paragraphStyle = NSMutableParagraphStyle()
        paragraphStyle.firstLineHeadIndent = firstLineIndent
        let attrString = NSAttributedString(
            string: text,
            attributes: [
                .paragraphStyle: paragraphStyle,
                .font: font
            ]
        )
        uiView.attributedText = attrString
    }
}

// 在你的ZStack中使用
ZStack {
    Image.book
        .resizable()
        .aspectRatio(contentMode: .fit)
        .frame(width: 12, height: 10)
    IndentedTextLabel(
        text: entry.verse,
        font: UIFont(name: "OpenSans-Regular", size: 11)!,
        firstLineIndent: 16
    )
}

内容的提问来源于stack exchange，提问作者kunass2