Xcode HTML到字符串返回零？- SWIFT 3

Posted 2023-03-11

【中文标题】Xcode HTML到字符串返回零？- SWIFT 3

【英文标题】：Xcode HTML to String return nil ?- SWIFT 3

【发布时间】：2018-03-30 00:21:41

【问题描述】：

public func sethtmlBody(_ body: String, bounds: CGRect = UIScreen.main.bounds) -> String 

    let font = "-apple-system"
    let fontSize = 19
    let fontColor = "#000000"
    let lineHeight = 25
    let imageWidth = bounds.width - 40
    let margin = 20
    let codeStyle = "pre[class*=\"language-\"]background:white;border-radius:14px;color:black;display:block;font-size:16px;font-weight:500;padding:20px;overflow-x:auto;white-space:pre-wrap;line-height:130%;pre.language-coffeescript .token.commentcolor:#6a7576pre.language-coffeescript .token.stringcolor:#8ADC64pre.language-coffeescript .token.number,pre.language-coffeescript .token.operatorcolor:#a580f8pre.language-coffeescript .token.keyword,pre.language-coffeescript .token.class-name,pre.language-coffeescript .token.functioncolor:#8dfpre.language-swift .token.commentcolor:#690pre.language-swift .token.stringcolor:#ee433fpre.language-swift .token.keywordcolor:#C945A7pre.language-swift .token.number,pre.language-swift .token.function,pre.language-swift .token.builtin,pre.language-swift .token.class-namecolor:#5C2699"

    let htmlString = "<style>p, li  font-family:\"\(font)\"; color: \(fontColor); font-size:\(fontSize)px; line-height:\(lineHeight)px  p  margin: \(margin)px 0;  img  max-width: \(imageWidth)px;  #p  font-weight: bold; font-size: 24px; line-height: 130%; margin: 50px 20px;  ul li, ol li  margin: 20px 0; font-weight: bold;  \(codeStyle)</style>\(body)"

    return htmlString

我正在使用 swift 3。为什么该函数将我返回为 Nil？

签名：

bodyAttributedString = setHtmlBody(sectionBody).htmlToAttributedString

【问题讨论】：

你的函数返回String，而不是String?。所以它不能为零

bodyAttributedString = setHtmlBody(sectionBody).htmlToAttributedString，在这种情况下，没有

什么是htmlToAttributedString？这不是标准库或基金会、AFAIK 中 String 的属性。

【参考方案1】：

这将是htmlToAttributedString 功能所有其他工作正常的问题。我用类似的方法尝试过，它对我来说非常有效

请检查...

扩展将html作为属性字符串

extension Data 
    var htmlToAttributedString: NSAttributedString? 
        do 
            return try NSAttributedString(data: self, options: [.documentType: NSAttributedString.DocumentType.html, .characterEncoding: String.Encoding.utf8.rawValue], documentAttributes: nil)
         catch 
            print("error:", error)
            return  nil
        
    
    var html2String: String 
        return htmlToAttributedString?.string ?? ""
    


extension String 
    var htmlToAttributedString: NSAttributedString? 
        return Data(utf8).htmlToAttributedString
    
    var html2String: String 
        return htmlToAttributedString?.string ?? ""
    

HTML 字符串构建函数

public func setHtmlBody(_ body: String, bounds: CGRect = UIScreen.main.bounds) -> String 

    let font = "-apple-system"
    let fontSize = 19
    let fontColor = "#000000"
    let lineHeight = 25
    let imageWidth = bounds.width - 40
    let margin = 20
    let codeStyle = "pre[class*=\"language-\"]background:white;border-radius:14px;color:black;display:block;font-size:16px;font-weight:500;padding:20px;overflow-x:auto;white-space:pre-wrap;line-height:130%;pre.language-coffeescript .token.commentcolor:#6a7576pre.language-coffeescript .token.stringcolor:#8ADC64pre.language-coffeescript .token.number,pre.language-coffeescript .token.operatorcolor:#a580f8pre.language-coffeescript .token.keyword,pre.language-coffeescript .token.class-name,pre.language-coffeescript .token.functioncolor:#8dfpre.language-swift .token.commentcolor:#690pre.language-swift .token.stringcolor:#ee433fpre.language-swift .token.keywordcolor:#C945A7pre.language-swift .token.number,pre.language-swift .token.function,pre.language-swift .token.builtin,pre.language-swift .token.class-namecolor:#5C2699"

    let htmlString = "<style>p, li  font-family:\"\(font)\"; color: \(fontColor); font-size:\(fontSize)px; line-height:\(lineHeight)px  p  margin: \(margin)px 0;  img  max-width: \(imageWidth)px;  #p  font-weight: bold; font-size: 24px; line-height: 130%; margin: 50px 20px;  ul li, ol li  margin: 20px 0; font-weight: bold;  \(codeStyle)</style>\(body)"
    return htmlString

演示文稿

override func viewDidLoad() 
    super.viewDidLoad()

    let body = "<p>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p>"

    let htmlString = setHtmlBody(body)


    if let attributedString = htmlString.htmlToAttributedString 
        self.labelHTML.attributedText = attributedString
    
 

输出