How to check validity of URL in Swift?

Question

Trying to make an app launch the default browser to a URL, but only if the URL entered is valid, otherwise it displays a message saying the URL is invalid.

How would

Answer 1

This is for latest Swift 4, based on Doug Amos answer (for swift 3)

public static func verifyUrl (urlString: String?) -> Bool {
    //Check for nil
    if let urlString = urlString {
        // create NSURL instance
        if let url = NSURL(string: urlString) {
            // check if your application can open the NSURL instance
            return UIApplication.shared.canOpenURL(url as URL)
        }
    }
    return false
}