问如何在iPhone上验证url

EN

import Foundation

// A private global detector variable which can be reused.
private let detector = try! NSDataDetector(types: NSTextCheckingType.Link.rawValue)

extension String {
  func URL() -> NSURL? {
    let textRange = NSMakeRange(0, self.characters.count)
    guard let URLResult = detector.firstMatchInString(self, options: [], range: textRange) else {
      return nil
    }

    // This checks that the whole string is the detected URL. In case
    // you don't have such a requirement, you can remove this code
    // and return the URL from URLResult.
    guard NSEqualRanges(URLResult.range, textRange) else {
      return nil
    }

    return NSURL(string: self)
  }
}