在 swift 3 中的 textview 中显示属性文本？

Question

我想以斜体显示文本，从服务器接收到的粗体。

你好世界

所以，

responseObj!["text"] = "<p><b><i>hello</i></b><i>world</></p>"
     if let postText:String = responseObj!["text"] as? String{
          let str = try NSAttributedString(data: postText.data(using: String.Encoding.unicode, allowLossyConversion: true)!, options: [ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType], documentAttributes: nil)
      self.textView.attributedText = str
    }

当我像这样添加时，意味着我的文本显示正常而不应用粗体和斜体。我希望文本以粗体、斜体显示。

Answer 1

编辑：更新 Swift 4

为String 创建一个extension：

extension String {
    func htmlAttributedString(fontSize: CGFloat = 17.0) -> NSAttributedString? {
        let fontName = UIFont.systemFont(ofSize: fontSize).fontName
        let string = self.appending(String(format: "<style>body{font-family: '%@'; font-size:%fpx;}</style>", fontName, fontSize))
        guard let data = string.data(using: String.Encoding.utf16, allowLossyConversion: false) else { return nil }

        guard let html = try? NSMutableAttributedString (
             data: data,
             options: [NSAttributedString.DocumentReadingOptionKey.documentType: NSAttributedString.DocumentType.html],
             documentAttributes: nil) else { return nil }
        return html
    }
}

在项目的任何地方调用它：

text.htmlAttributedString() // will set fontSize with 17.0 which is the default value


text.htmlAttributedString(fontSize: 14.0) // pass your required fontSize

注意，let string = self.appending(String(format: "<style>body{font-family: '%@'; font-size:%fpx;}</style>", fontName, fontSize)) 用于保持字符串字体与默认 iOS 平台中使用的字体相同。

要在UITextView 上设置字符串，请使用：

textView.attributedText = textToBeConverted.htmlAttributedString() ?? ""

结果：

Answer 2

从下面的函数将属性文本分配给 UITextView，

//HTML to Attributed text
func stringFromHtml(string: String) -> NSAttributedString? {
do {
    let data = string.data(using: String.Encoding.utf8, allowLossyConversion: true)
    if let d = data {
        let str = try NSAttributedString(data: d,
                                         options: [NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType],
                                         documentAttributes: nil)
        return str
    }
} catch {
}
return nil
}

//This will give you attributed text which you have to assign to your UITextView. and whatever string having html tag that you have to pass inside this function.

//Below code will conver attributed text to HTML Text
//Attributed to HTML text

    let attrStr = self.txtView.attributedText
    let documentAttributes = [NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType]
    do {
        let htmlData = try attrStr?.data(from: NSMakeRange(0, (attrStr?.length)!), documentAttributes:documentAttributes)
        if let htmlString = String(data:htmlData!, encoding:String.Encoding.utf8) {
            print(htmlString)
        }
    }
    catch {
        print("error creating HTML from Attributed String")
    }