Underline part of a string using NSMutableAttributedString in iOS 8 is not working

Question

I try to underline part of a string, for example, a \'string\' part in \'test string\' string. I\'m using NSMutableAttributedString and my sol

Answer 1

It's September 2018, so this answer is not about iOS8 but it still relates to underlining part of a string.

Here is a Swift 4 extension that underlines a given term within an already composed myAttributedString

extension NSMutableAttributedString {

    func underline(term: String) {

        guard let underlineRange = string.range(of: term) else {

            return
        }

        let startPosition = string.distance(from: term.startIndex, to: underlineRange.lowerBound)
        let nsrange = NSRange(location: startPosition, length: term.count)

        addAttribute(
            .underlineStyle,
            value: NSUnderlineStyle.styleSingle.rawValue,
            range: nsrange)
    }
}

Usage: myAttributedString.underline(term: "some term")