目錄

• 1、HTML標(biāo)簽轉(zhuǎn) 富文本
• 2、計(jì)算富文本的Size
• 3、處理標(biāo)簽中包含 p 標(biāo)簽換行(獨(dú)占一行)的問(wèn)題

一、HTML標(biāo)簽轉(zhuǎn) 富文本（這里寫(xiě)到String的擴(kuò)展里面了）

extension String {
    /// String 或者String HTML標(biāo)簽 轉(zhuǎn) html 富文本設(shè)置
    /// - Parameters:
    ///   - font: 設(shè)置字體
    ///   - lineSpacing: 設(shè)置行高
    /// - Returns: 默認(rèn)不將 \n替換<br/> 返回處理好的富文本
    func setHtmlAttributedString(font: UIFont? = UIFont.systemFont(ofSize: 16), lineSpacing: CGFloat? = 10) -> NSMutableAttributedString {
        var htmlString: NSMutableAttributedString? = nil
        do {
            if let data = self.replacingOccurrences(of: "\n", with: "<br/>").data(using: .utf8) {
                htmlString = try NSMutableAttributedString(data: data, options: [
                NSAttributedString.DocumentReadingOptionKey.documentType: NSAttributedString.DocumentType.html,
                NSAttributedString.DocumentReadingOptionKey.characterEncoding: NSNumber(value: String.Encoding.utf8.rawValue)], documentAttributes: nil)
                let wrapHtmlString = NSMutableAttributedString(string: "\n")
                // 判斷尾部是否是換行符
                if let weakHtmlString = htmlString, weakHtmlString.string.hasSuffix("\n") {
                    htmlString?.deleteCharacters(in: NSRange(location: weakHtmlString.length - wrapHtmlString.length, length: wrapHtmlString.length))
                }
            }
        } catch {
        }
        // 設(shè)置富文本字的大小
        if let font = font {
            htmlString?.addAttributes([
            NSAttributedString.Key.font: font], range: NSRange(location: 0, length: htmlString?.length ?? 0))
        }
    
        // 設(shè)置行間距
        if let weakLineSpacing = lineSpacing {
            let paragraphStyle = NSMutableParagraphStyle()
            paragraphStyle.lineSpacing = weakLineSpacing
            htmlString?.addAttribute(.paragraphStyle, value: paragraphStyle, range: NSRange(location: 0, length: htmlString?.length ?? 0))
        }
        return htmlString ?? NSMutableAttributedString(string: self)
    }
}

二、計(jì)算富文本的Size

let strHtml = "<p style='color:green'>首付<span style='color:#e83c36;'>5000元</span>，提前付<span style='color:red'>3倍月供</span>，月供<span style='color:red'>3000元</span>(48期)</p>"
let attributedText = strHtml.setHtmlAttributedString(font: UIFont.systemFont(ofSize: 20), lineSpacing: 10)
let textSize = attributedText.boundingRect(with: CGSize(width: kScreenW - 40, height: CGFloat.greatestFiniteMagnitude), options: [.usesLineFragmentOrigin, .usesFontLeading], context: nil).size 

三、處理標(biāo)簽中包含 p 標(biāo)簽換行(獨(dú)占一行)的問(wèn)題

• 3.1、問(wèn)題描述：如果p標(biāo)簽是最大的標(biāo)簽，生成的富文本會(huì)自動(dòng)換行，展示的時(shí)候多一行的高度，如下

  
  
  p標(biāo)簽造成的問(wèn)題

• 3.2、目前的處理辦法：判斷生成的富文本字符串結(jié)尾里面是否有 \n，如果有我們就刪除掉，代碼如下，htmlString是 HTML標(biāo)簽轉(zhuǎn)化后的富文本

  let wrapHtmlString = NSMutableAttributedString(string: "\n")
   // 判斷尾部是否是換行符
  if let weakHtmlString = htmlString, weakHtmlString.string.hasSuffix("\n") {
        htmlString?.deleteCharacters(in: NSRange(location: weakHtmlString.length - wrapHtmlString.length, length: wrapHtmlString.length))
  }
  

  處理后的效果圖如下

  
  
  處理后的效果圖

具體的 測(cè)試用例 在 StringExtensionViewController.swift 的 test119() 方法里面