Convert HTML to NSAttributedString in iOS

Question

I am using a instance of UIWebView to process some text and color it correctly, it gives the result as HTML but rather than displaying it in the UIWebView I want to display it using Core Text with a NSAttributedString.

I am able to create and draw the NSAttributedString but I am unsure how I can convert and map the HTML into the attributed string.

I understand that under Mac OS X NSAttributedString has a initWithHTML: method but this was a Mac only addition and is not available for iOS.

I also know that there is a similar question to this but it had no answers, I though I would try again and see whether anyone has created a way to do this and if so, if they could share it.

Answer 1

In iOS 7, UIKit added an initWithData:options:documentAttributes:error: method which can initialize an NSAttributedString using HTML, eg:

[[NSAttributedString alloc] initWithData:[htmlString dataUsingEncoding:NSUTF8StringEncoding] 
                                 options:@{NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType,
                                           NSCharacterEncodingDocumentAttribute: @(NSUTF8StringEncoding)} 
                      documentAttributes:nil error:nil];

In Swift:

let htmlData = NSString(string: details).data(using: String.Encoding.unicode.rawValue)
let options = [NSAttributedString.DocumentReadingOptionKey.documentType:
        NSAttributedString.DocumentType.html]
let attributedString = try? NSMutableAttributedString(data: htmlData ?? Data(),
                                                          options: options,
                                                          documentAttributes: nil)