如何将 AttributedString 转换为 NSMutableString Swift？

Question

我有 HTML 并被转换为 AttributedString。现在，我需要更改生成的属性字符串的字体，但我很难保留样式（粗体、斜体或常规）。

我找到了解决方案，但问题是我不知道如何使用它。他们使用 NSMutableAttributedString 作为扩展。我在底部粘贴了我的代码如何转换以及假定的解决方案。

谢谢你。

extension String {

 var htmlToAttributedString: NSAttributedString? {
        guard let data = data(using: .utf8) else { return NSAttributedString() }
        do {
            return try NSAttributedString(data: data, options: [.documentType: NSAttributedString.DocumentType.html, .characterEncoding:String.Encoding.utf8.rawValue], documentAttributes: nil)
        } catch {
            return NSAttributedString()
        }
    }

}






import Foundation

struct Service: Codable {

    var id: Int
    var name: String?
    var price: String?
    var description: String?
    var subtitle: String?
    var bodyPreview: String?
    var featuredImage: String? // For FindAll
    var imageList: [String]? // For FindByID

    private enum CodingKeys: String, CodingKey {
        case id
        case name
        case price
        case subtitle
        case description
        case bodyPreview = "body_preview"
        case featuredImage = "featured_image_url"
        case imageList = "images_url"
    }

}



class ServiceDetailViewController: UIViewController {


    private var service: Service?

    private func showServiceDetails() {
        detailLabel.attributedText = service?.description?.htmlToAttributedString
        collectionView.reloadData()
        startCollectionViewTimer()
    }

}

Manmal的解决方案：

extension NSMutableAttributedString {
    func setFontFace(font: UIFont, color: UIColor? = nil) {
        beginEditing()
        self.enumerateAttribute(
            .font,
            in: NSRange(location: 0, length: self.length)
        ) { (value, range, stop) in

            if let f = value as? UIFont,
                let newFontDescriptor = f.fontDescriptor
                    .withFamily(font.familyName)
                    .withSymbolicTraits(f.fontDescriptor.symbolicTraits) {

                let newFont = UIFont(
                    descriptor: newFontDescriptor,
                    size: font.pointSize
                )
                removeAttribute(.font, range: range)
                addAttribute(.font, value: newFont, range: range)
                if let color = color {
                    removeAttribute(
                        .foregroundColor,
                        range: range
                    )
                    addAttribute(
                        .foregroundColor,
                        value: color,
                        range: range
                    )
                }
            }
        }
        endEditing()
    }
}

Answer 1

let attriString = NSAttributedString(string:"attriString", 属性: [NSAttributedString.Key.foregroundColor: UIColor.lightGray, NSAttributedString.Key.font: AttriFont])

Answer 2

您可以简单地创建一个类似的扩展来返回可变的属性字符串：

extension String {
    var htmlToMutableAttributedString: NSMutableAttributedString? {
        do {
            return try .init(data: Data(utf8), options: [.documentType:  NSAttributedString.DocumentType.html, .characterEncoding: String.Encoding.utf8.rawValue], documentAttributes: nil)
        } catch {
            print(error)
            return nil
        }
    }
}

Answer 3

关于反向转换，请参阅爱斯基摩人的答案https://developer.apple.com/forums/thread/682431

let mutableAttributedString = NSMutableAttributedString("… something …")
let attributedString = try? AttributedString(mutableAttributedString, including: \.foundation)