UITextView linkTextAttributes font attribute not applied to NSAttributedString

For some reason postprocessing attributed string with enumerateAttributesInRange: do not work for me.

So I used NSDataDetector to detect link and enumerateMatchesInString:options:range:usingBlock: to put my style for all links in string. Here is my processing function:

+ (void) postProcessTextViewLinksStyle:(UITextView *) textView {
   NSAttributedString *attributedString = textView.attributedText;
   NSMutableAttributedString *attributedStringWithItalicLinks = [[NSMutableAttributedString alloc] initWithAttributedString:attributedString];

   NSError *error = nil;
   NSDataDetector *detector = [NSDataDetector dataDetectorWithTypes:NSTextCheckingTypeLink
                                                           error:&error];

   [detector enumerateMatchesInString:[attributedString string]
                           options:0
                             range:NSMakeRange(0, [attributedString length])
                        usingBlock:^(NSTextCheckingResult *match, NSMatchingFlags flags, BOOL *stop){
                            NSRange matchRange = [match range];
                            NSLog(@"Links style postprocessing. Range (from: %lu, length: %lu )", (unsigned long)matchRange.location, (unsigned long)matchRange.length);
                            if ([match resultType] == NSTextCheckingTypeLink) {                                    
                                [attributedStringWithItalicLinks removeAttribute:NSFontAttributeName range:matchRange];
                                [attributedStringWithItalicLinks addAttribute:NSFontAttributeName value:[UIFont fontWithName:@"YourFont-Italic" size:14.0f] range:matchRange];
                            }
                        }];

   textView.attributedText = attributedStringWithItalicLinks;
}

This is a swift 3 update of answer above from @Arun Ammannaya

guard let font = UIFont.init(name: "Roboto-Regular", size: 15) else {
    return
}
let newString = NSMutableAttributedString(attributedString: string)
let range = NSRange(location:0,length: string.length)
string.enumerateAttributes(in: range, options: .reverse, using: { (attributes : [String : Any], range : NSRange, _) -> Void in
    if let _ = attributes[NSLinkAttributeName] {
        newString.removeAttribute(NSFontAttributeName, range: range)
        newString.addAttribute(NSFontAttributeName, value: font, range: range)
    }
})
errorTextView.attributedText = newString
errorTextView.linkTextAttributes = [NSForegroundColorAttributeName : UIColor.green, NSUnderlineStyleAttributeName : NSUnderlineStyle.styleSingle.rawValue]

This is a Swift 3 solution to @CTiPKA which I prefer since it avoids HTML

guard let attributedString = errorTextView.attributedText else {
    return
}
guard let font = UIFont.init(name: "Roboto-Regular", size: 15) else {
   return
}
let newString = NSMutableAttributedString(attributedString: attributedString)

let types: NSTextCheckingResult.CheckingType = [.link, .phoneNumber]

guard let linkDetector = try? NSDataDetector(types: types.rawValue) else { return  }
let range = NSRange(location:0,length: attributedString.length)

linkDetector.enumerateMatches(in: attributedString.string, options: [], range: range, using: { (match : NSTextCheckingResult?,
    flags : NSRegularExpression.MatchingFlags, stop) in

    if let matchRange = match?.range {
        newString.removeAttribute(NSFontAttributeName, range: matchRange)
        newString.addAttribute(NSFontAttributeName, value: font, range: matchRange)
    }
})
errorTextView.attributedText = newString

Not sure why linkTextAttributes doesn't work for the font name. But we can achieve this by updating the link attributes of the NSAttributedString. Check the code below.

        do {
        let htmlStringCode = "For more info <a href=\"http://www.samplelink.com/subpage.php?id=8\">Click here</a>"

        let string = try NSAttributedString(data: htmlStringCode.dataUsingEncoding(NSUTF8StringEncoding)!, options: [NSDocumentTypeDocumentAttribute:NSHTMLTextDocumentType, NSCharacterEncodingDocumentAttribute: NSUTF8StringEncoding], documentAttributes: nil)

        let newString = NSMutableAttributedString(attributedString: string)
        string.enumerateAttributesInRange(NSRange.init(location: 0, length: string.length), options: .Reverse) { (attributes : [String : AnyObject], range:NSRange, _) -> Void in
            if let _ = attributes[NSLinkAttributeName] {
                newString.removeAttribute(NSFontAttributeName, range: range)
                newString.addAttribute(NSFontAttributeName, value: UIFont.systemFontOfSize(30), range: range)
            }
        }
        textField.attributedText = newString
        textField.linkTextAttributes = [NSForegroundColorAttributeName : UIColor.redColor(), NSUnderlineStyleAttributeName : NSUnderlineStyle.StyleNone.rawValue]

    }catch {
    }

This is the objective-C code for this:

NSDictionary *options = @{NSDocumentTypeDocumentAttribute : NSHTMLTextDocumentType};
NSData *data = [html dataUsingEncoding:NSUnicodeStringEncoding allowLossyConversion:NO];

NSAttributedString *attributedString = [[NSAttributedString alloc] initWithData:data options:options documentAttributes:nil error:nil];
NSMutableAttributedString *attributedStringWithBoldLinks = [[NSMutableAttributedString alloc] initWithAttributedString:attributedString];

[attributedString enumerateAttributesInRange:NSMakeRange(0, attributedString.string.length) options:NSAttributedStringEnumerationReverse usingBlock:^(NSDictionary<NSString *,id> * _Nonnull attrs, NSRange range, BOOL * _Nonnull stop) {

    if ([attrs objectForKey:NSLinkAttributeName]) {
        [attributedStringWithBoldLinks removeAttribute:NSFontAttributeName range:range];
        [attributedStringWithBoldLinks addAttribute:NSFontAttributeName value:[UIFont fontWithName:@"YourFont-Bold" size:16.0] range:range];
    }
}];

self.linkTextAttributes = @{NSForegroundColorAttributeName : [UIColor redColor]};

self.attributedText = attributedStringWithBoldLinks;