How to make tappable links in NSAttributedString

Swift version: 5.10

Paul Hudson @twostraws June 1st 2019

You can make interactive hyperlinks in any attributed string, which in turn means you can add interactive hyperlinks to any UIKit control. If you're working with UITextView (which is likely, let's face it), you get basic hyperlinks just by enabling the "Links" data detector in Interface Builder, but that doesn't work for arbitrary strings – for example, maybe you want the words “tap here" to be interactive.

Here is a complete example of arbitrary hyperlinks using a UITextView. Make sure your text view has "Selectable" enabled, as this is required by iOS:

class ViewController: UIViewController, UITextViewDelegate {
    @IBOutlet var textView: UITextView!

    override func viewDidLoad() {
        let attributedString = NSMutableAttributedString(string: "Want to learn iOS? You should visit the best source of free iOS tutorials!")
        attributedString.addAttribute(.link, value: "https://www.hackingwithswift.com", range: NSRange(location: 19, length: 55))

        textView.attributedText = attributedString
    }

    func textView(_ textView: UITextView, shouldInteractWith URL: URL, in characterRange: NSRange, interaction: UITextItemInteraction) -> Bool {
        UIApplication.shared.open(URL)
        return false
    }
}

There are three important things to note about this technique.

First, your view controller should be set as the delegate for your text view in Interface Builder or in code.

Second, the tap cannot be very brief, which means quick taps are ignored by iOS. If you find find this annoying you might consider something like this: https://gist.github.com/benjaminbojko/c92ac19fe4db3302bd28.

Third, this technique is easily used with custom URL schemes, e.g. yourapp://, which you can catch and parse inside shouldInteractWith to trigger your own behaviors.