Swift-更改具有自己样式的HTML字符串上的字体 | 更改具有自己样式的HTML字符串上的字体

本文介绍了Swift-更改具有自己样式的HTML字符串上的字体的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我正在从Wordpress API获取HTML字符串并将其解析为Attributed String以在我的应用中显示它。由于字符串有自己的样式，它会显示不同的字体和大小，这会影响我们的设计选择。

I am dinamically getting an HTML string from a Wordpress API and parsing it into an Attributed String to show it in my app. Since the string has its own styles, it shows different fonts and sizes, something that is affecting our design choices.

我想要做的是更改字体及其大小整个属性字符串。

What I want to do is change the font and its size on the whole attributed string.

我尝试在属性字符串的选项中这样做，但它什么都不做：

I tried doing so in the options of the attributed string, but it does nothing:

let attributedT = try! NSAttributedString(
            data: nContent!.decodeHTML().data(using: String.Encoding.unicode, allowLossyConversion: true)!,
            options: [ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType, NSFontAttributeName: UIFont(name: "Helvetica", size: 16.0)!],
            documentAttributes: nil)
        contentLbl.attributedText = attributedT

有没有人对如何实现这个目的有任何想法？

Does anybody have any ideas on how to achieve this?

PS我知道我可以在字符串的开头或结尾添加一个CSS标签，但这会覆盖其中的其他样式吗？此外，如果这是一个有效的解决方案，你能否提供一个如何做的样本？

P.S. I know that I could add a CSS tag to the beginning or end of the string, but would this override other styles in it? Also, if this is a valid solution, could you please provide a sample on how to do it?

推荐答案

setAttributes将重置来自HTML的所有属性。我写了一个扩展方法来避免这种情况：

The setAttributes will reset all the attributes from HTML. I wrote an extension method to avoid this:

Swift 4

public convenience init?(HTMLString html: String, font: UIFont? = nil) throws {
    let options : [NSAttributedString.DocumentReadingOptionKey : Any] =
        [NSAttributedString.DocumentReadingOptionKey.documentType: NSAttributedString.DocumentType.html,
         NSAttributedString.DocumentReadingOptionKey.characterEncoding: String.Encoding.utf8.rawValue]

    guard let data = html.data(using: .utf8, allowLossyConversion: true) else {
        throw NSError(domain: "Parse Error", code: 0, userInfo: nil)
    }

    if let font = font {
        guard let attr = try? NSMutableAttributedString(data: data, options: options, documentAttributes: nil) else {
            throw NSError(domain: "Parse Error", code: 0, userInfo: nil)
        }
        var attrs = attr.attributes(at: 0, effectiveRange: nil)
        attrs[NSAttributedStringKey.font] = font
        attr.setAttributes(attrs, range: NSRange(location: 0, length: attr.length))
        self.init(attributedString: attr)
    } else {
        try? self.init(data: data, options: options, documentAttributes: nil)
    }
}

测试样本：

let html = "<html><body><h1 style=\"color:red;\">html text here</h1></body></html>"
let font = UIFont.systemFont(ofSize: 16)

var attr = try NSMutableAttributedString(HTMLString: html, font: nil)
var attrs = attr?.attributes(at: 0, effectiveRange: nil)
attrs?[NSAttributedStringKey.font] as? UIFont
// print: <UICTFont: 0x7ff19fd0a530> font-family: "TimesNewRomanPS-BoldMT"; font-weight: bold; font-style: normal; font-size: 24.00pt

attr = try NSMutableAttributedString(HTMLString: html, font: font)
attrs = attr?.attributes(at: 0, effectiveRange: nil)
attrs?[NSAttributedStringKey.font] as? UIFont
// print: <UICTFont: 0x7f8c0cc04620> font-family: ".SFUIText"; font-weight: normal; font-style: normal; font-size: 16.00pt

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