Xcode 9.1 Swift 4，如果使用“if #available”，则无法使用 NSDocumentTypeDocumentAttribute 进行编译
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Xcode 9.1 Swift 4, unable to compile with NSDocumentTypeDocumentAttribute if "if #available" is used
提问by Jan Válek
Hi I have app with is targeting iOS8.2 in deployment target setting. I tried to convert app to swift 4 from swift3. It works, but is not working in simulator of iPhone 5s iOS 8.4. Problem is this:
嗨，我的应用程序在部署目标设置中针对 iOS8.2。我试图将应用程序从 swift3 转换为 swift 4。它可以工作，但不能在 iPhone 5s iOS 8.4 的模拟器中工作。问题是这样的：
cell.lblHeader.attributedText = try NSAttributedString(data: htmlData, options: [NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType], documentAttributes: nil)
So i tried this:
所以我试过这个：
if #available(iOS 11, *){
cell.lblHeader.attributedText = try NSAttributedString(data: htmlData, options: [NSAttributedString.DocumentReadingOptionKey.documentType: NSAttributedString.DocumentType.html], documentAttributes: nil)
}
if #available(iOS 8.4, *){
cell.lblHeader.attributedText = try NSAttributedString(data: htmlData, options: [NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType], documentAttributes: nil)
}
But I'm unable to compile this code Xcode is displaying exception for iOS 8.4 branch:
但我无法编译此代码 Xcode 显示 iOS 8.4 分支异常：
Cannot convert value of type 'NSAttributedString.DocumentAttributeKey' to expected dictionary key type 'NSAttributedString.DocumentReadingOptionKey'
I have opinion about setting base sdk to 8.x but I don't found ho to do it. In build setting I'm able to set base sdk only to 11.x version.
我对将基础 sdk 设置为 8.x 有意见，但我没有找到这样做的机会。在构建设置中，我只能将基础 sdk 设置为 11.x 版本。
I will be thankful for every idea.
我会感谢每一个想法。
回答by RoyBS
Use this line only:
仅使用此行：
cell.lblHeader.attributedText = try NSAttributedString(data: htmlData, options: [NSAttributedString.DocumentReadingOptionKey.documentType: NSAttributedString.DocumentType.html], documentAttributes: nil)
回答by Serj Rubens
Seems like thats a correct syntax for Swift 4.1.2:
似乎这是Swift 4.1.2的正确语法：
let options: [NSAttributedString.DocumentReadingOptionKey: Any] = [
NSAttributedString.DocumentReadingOptionKey.documentType: NSAttributedString.DocumentType.html,
NSAttributedString.DocumentReadingOptionKey.characterEncoding: String.Encoding.utf8.rawValue
]
回答by Zgpeace
It works in swift 5.
它适用于 swift 5。
let htmlString = """
<html>
<head><style type=\"text/css\">body { font-family: Mehr Nastaliq Web; font-size: 22pt; white-space: pre-wrap; text-align: right; lang: en; direction: RTL; -webkit-user-select: none; meta charset=\"UTF-8\" }</style> </head>
<body leftmargin=\"20\" topmargin=\"0\" rightmargin=\"20\">hello world! Arabic.?????? ????? ?? ???? ?????? ????? ?? ???? ????? ?? ????? ????? ???? ???? ????? ?? ??? ????? </body>
</html>
"""
let attributedString = try? NSAttributedString(data:
htmlString.data(using: String.Encoding.unicode)!, options: [NSAttributedString.DocumentReadingOptionKey.documentType: NSAttributedString.DocumentType.html], documentAttributes: nil)
回答by Andrey Gerashchenko
It works great with Swift 4.0:
它适用于 Swift 4.0：
let documentKey = NSAttributedStringKey("NSDocumentTypeDocumentAttribute")
let charsetKey = NSAttributedStringKey("NSCharacterEncodingDocumentAttribute")
let string = NSAttributedString(string: htmlString,
attributes: [documentKey: NSAttributedString.DocumentType.html,
charsetKey: String.Encoding.utf8.rawValue])
