如何在 Swift 的 UITextView 中维护 HTML 内容的缩进？答案

【问题标题】：How to maintain indentations of HTML content in UITextView in Swift?如何在 Swift 的 UITextView 中维护 HTML 内容的缩进？
【发布时间】：2018-10-25 01:19:14
【问题描述】：

我在UITextView 中显示列表和子列表，但它没有显示子列表的缩进。这是我的代码，从这里获取 HTML 格式的数据。

extension NSAttributedString {
convenience public init?(styled: String, textAlignment: NSTextAlignment = .center, color: UIColor = .black) {
    guard let data = styled.data(using: String.Encoding.unicode) else {
        return nil
    }
    do {
        let string = try NSMutableAttributedString(data: data,
                                                   options: [NSAttributedString.DocumentReadingOptionKey.documentType: NSAttributedString.DocumentType.html], documentAttributes: nil)
        let paragraphStyle = NSMutableParagraphStyle()

        paragraphStyle.tabStops = [NSTextTab(textAlignment: .natural, location: 0, options: Dictionary<NSTextTab.OptionKey, Any>())]
        paragraphStyle.defaultTabInterval = 5

        string.addAttributes(
            [NSAttributedStringKey.foregroundColor: color,NSAttributedStringKey.paragraphStyle:paragraphStyle],
            range: NSMakeRange(0, string.length)
        )

        self.init(attributedString: string.removingTrailingNewLine)
    } catch {
        return nil
    }
}

要显示的 HTML 数据，虽然它包含 ul、ol 标签，但为这些标签添加 CSS 不适用于 UITextView。

    <html>

    <head>
    <style type="text/css">
    body {
      font-size: 14px;
      font-family: -apple-system, Arial, sans-serif;
      color: black;
      margin-bottom: 0px;
      padding-bottom: 0px;
      line-height: 20px;
    }

    ul,
    ol {
      padding-left: 10px;
    }
    </style>
    </head>

    <body>
    <p>Professionals are often vastly more comfortable solving analytical, convergent problems than those requiring more divergent thinking. In this article, Olivier Leclerc and Mihnea Moldoveanu share some strategies for stimulating truly novel thinking.
    They introduce five "flexons," which can be thought of as "languages" for shaping problems that help you bring diverse perspectives to problem solving:</p>

  <ul type="disc">
    <li>Networks</li>
    <li>Evolutionary</li>
  </ul>


  <ol>
    <li>Decision-agent</li>
    <li>System dynamics</li>
    <li>Information-processing :
      <ol>
        <li>Decision-agent</li>
        <li>System dynamics</li>
        <li>Information-processing</li>
      </ol>
    </li>
  </ol>


  <ul type="disc">
    <li>Networks :
      <ul>
        <li type="circle">Decision-agent</li>
        <li type="circle">System dynamics</li>
      </ul>
    </li>
  </ul>

</body>

</html>

这是它在设备上的显示方式。我想指出的另一件事是，如果我从 Swift 端添加段落样式，然后列表显示如下，如果我不添加段落样式，则添加列表，然后填充超出我的要求。

【问题讨论】：

HTML 示例在哪里？只需添加它
@AbdelahadDarwish 也添加了 HTML 和一些细节。

标签： ios swift uitextview padding nsattributedstring

【解决方案1】：

只要收到Html数据就用attributedText显示

将html转换为AttributedString：

    // Read Html of Your example From Bundle

    guard let  htmlFile =  Bundle.main.path(forResource: "dataHtml", ofType: "html") else { return}

    // Safe convert html to string
    guard let  html =  try? String(contentsOfFile: htmlFile, encoding: String.Encoding.utf8)else { return}

    let options = [NSAttributedString.DocumentReadingOptionKey.documentType: NSAttributedString.DocumentType.html]

    // Safe string  to Data

    guard let  htmlData =  NSString(string: html).data(using: String.Encoding.unicode.rawValue) else { return}

    // Safe attributedString from data
    guard let  attributedString =  try? NSAttributedString(data: htmlData, options: options, documentAttributes: nil) else { return}

    textView.attributedText = attributedString
    textView.textColor = .red // you can comment  or change font and color

您的示例结果：

【讨论】：

我想使用ul,ol{padding-left: 10px;} 控制填充，但它不起作用，知道吗？
你可以在显示前对html进行处理，我会为你做几分钟