How to display html formatted text in ios label

问题

I would like to display html formatted text on a UILabel in IOS.

In Android, it has api like this .setText(Html.fromHtml(somestring));

Set TextView text from html-formatted string resource in XML

I would like to know what / if there is an equivalent in ios?

I search and find this thread:

How to show HTML text from API on the iPhone?

But it suggests using UIWebView. I need to display html formatted string in each table cell, so I think have 1 webview per row seems a bit heavy.

Is that any other alternative?

Thank you.

回答1:

Swift 3.0

do {
    let attrStr = try NSAttributedString(
        data: "<b><i>text</i></b>".data(using: String.Encoding.unicode, allowLossyConversion: true)!,
        options: [ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType],
        documentAttributes: nil)
    label.attributedText = attrStr
} catch let error {

}

回答2:

for Swift 2.0:

var attrStr = try! NSAttributedString(
        data: "<b><i>text</i></b>".dataUsingEncoding(NSUnicodeStringEncoding, allowLossyConversion: true)!,
        options: [ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType],
        documentAttributes: nil)
label.attributedText = attrStr

回答3:

You could try an attributed string:

var attrStr = NSAttributedString(
        data: "<b><i>text</i></b>".dataUsingEncoding(NSUnicodeStringEncoding, allowLossyConversion: true),
        options: [ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType],
        documentAttributes: nil,
        error: nil)
label.attributedText = attrStr

回答4:

Swift 4

import UIKit
let htmlString = "<html><body> Some <b>html</b> string </body></html>"
// works even without <html><body> </body></html> tags, BTW 
let data = htmlString.data(using: String.Encoding.unicode)! // mind "!"
let attrStr = try? NSAttributedString( // do catch
    data: data,
    options: [NSAttributedString.DocumentReadingOptionKey.documentType: NSAttributedString.DocumentType.html],
    documentAttributes: nil)
// suppose we have an UILabel, but any element with NSAttributedString will do
label.attributedText = attrStr

Supplement: controlling the font of resulting formatted string

To use properly scaled (i.e. with respect to user settings) system (or any other) font you may do the following.

let newFont = UIFontMetrics.default.scaledFont(for: UIFont.systemFont(ofSize: UIFont.systemFontSize)) // The same is possible for custom font.

let mattrStr = NSMutableAttributedString(attributedString: attrStr!)
mattrStr.beginEditing()
mattrStr.enumerateAttribute(.font, in: NSRange(location: 0, length: mattrStr.length), options: .longestEffectiveRangeNotRequired) { (value, range, _) in
    if let oFont = value as? UIFont, let newFontDescriptor = oFont.fontDescriptor.withFamily(newFont.familyName).withSymbolicTraits(oFont.fontDescriptor.symbolicTraits) {
        let nFont = UIFont(descriptor: newFontDescriptor, size: newFont.pointSize)
        mattrStr.removeAttribute(.font, range: range)
        mattrStr.addAttribute(.font, value: nFont, range: range)
    }
}
mattrStr.endEditing()
label.attributedText = mattrStr

回答5:

Try this:

let label : UILable! = String.stringFromHTML("html String")

func stringFromHTML( string: String?) -> String
    {
        do{
            let str = try NSAttributedString(data:string!.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: true
                )!, options:[NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType, NSCharacterEncodingDocumentAttribute: NSNumber(unsignedLong: NSUTF8StringEncoding)], documentAttributes: nil)
            return str.string
        } catch
        {
            print("html error\n",error)
        }
        return ""
    }
Hope its helpful.

回答6:

For me, Paul's answer worked. But for custom fonts I had to put following hack.

//Please take care of force unwrapping
let data = htmlString.data(using: String.Encoding.unicode)! 
        let mattrStr = try! NSMutableAttributedString(
            data: data,
            options: [NSAttributedString.DocumentReadingOptionKey.documentType: NSAttributedString.DocumentType.html],
            documentAttributes: nil)
        let normalFont = UIFontMetrics.default.scaledFont(for: UIFont(name: "NormalFontName", size: 15.0)!)//
        let boldFont = UIFontMetrics.default.scaledFont(for: UIFont(name: "BoldFontName", size: 15.0)!)
        mattrStr.beginEditing()
        mattrStr.enumerateAttribute(.font, in: NSRange(location: 0, length: mattrStr.length), options: .longestEffectiveRangeNotRequired) { (value, range, _) in
            if let oFont = value as? UIFont{
                mattrStr.removeAttribute(.font, range: range)
                if oFont.fontName.contains("Bold"){
                    mattrStr.addAttribute(.font, value: boldFont, range: range)
                }
                else{
                    mattrStr.addAttribute(.font, value: normalFont, range: range)
                }

            }
        }

来源：https://stackoverflow.com/questions/25879837/how-to-display-html-formatted-text-in-ios-label

标签

html

ios

swift

uiwebview

uilabel