Type of expression is ambiguous without more context attributed text in Swift 4

问题

I am using a font in the same in attribute: , it is giving above error

do {
        let myAttribute = [ NSAttributedStringKey.font: UIFont(name: "Chalkduster", size: 18.0)! ]


        let attrStr = try NSAttributedString(data: ("Some String HTML".data(using: String.Encoding.unicode, allowLossyConversion: false)!)!,options: [.documentType: NSAttributedString.DocumentType.html,
                                                       .characterEncoding: String.Encoding.utf8.rawValue],
                                             documentAttributes: nil,attributes: myAttribute)
        self.NoAccessMessage.font = UIFont(name: "Arial", size: 16.0)
        self.NoAccessMessage.attributedText = attrStr

    } catch let error {

    }

Please check if any help is required

回答1:

You are combining two different things. You can either apply an attribute to a string or read some HTML. Not both.

Perhaps you mean this:

let myAttribute = [ NSAttributedStringKey.font: UIFont(name: "Chalkduster", size: 18.0)! ]
let attrStr = NSAttributedString(string: "howdy there", attributes: myAttribute)

Or perhaps you mean this:

let html = "<p>howdy <b>there</b></p>"
let htmldata = html.data(using: .utf8)
let attrStr = try NSAttributedString(data: htmldata!, options: [.documentType : NSAttributedString.DocumentType.html], documentAttributes: nil)

Make up your mind which it is.

回答2:

Using this you can Apply both things (Swift 4 Code)

@IBOutlet weak var txtWv1: UITextView!
@IBOutlet weak var txtWv2: UITextView!

class SampleViewController: UIViewController{

    override func viewDidLoad() {
    super.viewDidLoad()

    // Sample HTML Text

    let html = "<ul> <li>Lorem ipsum dolor sit amet, consectetuer 
               adipiscing elit.</li> <li>Aliquam tincidunt mauris 
               eurisus.</li> <li>Vestibulum auctor dapibus neque.</li> 
               </ul>"

    do {

        let attrStr = try NSMutableAttributedString(data: html.data(using: 
            String.Encoding.unicode, allowLossyConversion: false)!,
            options: [.documentType: NSAttributedString.DocumentType.html,
                      .characterEncoding: String.Encoding.utf8.rawValue], 
                      documentAttributes: nil)

        // here is Your Attributed String
        txtWv1.attributedText = attrStr

        // Change Font or Color as per your requirement
        attrStr.setFontFace(font: UIFont(name: "Roboto-Bold", size: 20)!,color: UIColor.red)
        txtWv2.attributedText = attrStr

    } catch let error {
        print(error.localizedDescription)
    }

  }

}

You need to Create the Extension of NSMutableAttributedString as Following

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()
    }
}

Output is :

来源：https://stackoverflow.com/questions/51541557/type-of-expression-is-ambiguous-without-more-context-attributed-text-in-swift-4

标签

swift4

nsattributedstring