Email Address Validation in Swift

Email Address Validation in Swift

** Write in ViewController.swift

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var emailAddressTextField: UITextField!

    @IBOutlet weak var passwordTextField: UITextField!

    

    

    override func viewDidLoad() {

        super.viewDidLoad()

        // Do any additional setup after loading the view, typically from a nib.

    }

    override func didReceiveMemoryWarning() {

        super.didReceiveMemoryWarning()

        // Dispose of any resources that can be recreated.

    }

    @IBAction func signupButtonTapped(_ sender: AnyObject) {

        let providedEmailAddress = emailAddressTextField.text

        

        let isEmailAddressValid = isValidEmailAddress(emailAddressString: providedEmailAddress!)

        

        if isEmailAddressValid

        {

            print("Email address is valid")

        } else {

            print("Email address is not valid")

            displayAlertMessage(messageToDisplay: "Email address is not valid")

        }

        

    }

    

    func isValidEmailAddress(emailAddressString: String) -> Bool {

        

        var returnValue = true

        let emailRegEx = "[A-Z0-9a-z.-_]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,3}"

        

        do {

            let regex = try NSRegularExpression(pattern: emailRegEx)

            let nsString = emailAddressString as NSString

            let results = regex.matches(in: emailAddressString, range: NSRange(location: 0, length: nsString.length))

            

            if results.count == 0

            {

                returnValue = false

            }

            

        } catch let error as NSError {

            print("invalid regex: \(error.localizedDescription)")

            returnValue = false

        }

        

        return  returnValue

    }

    

    func displayAlertMessage(messageToDisplay: String)

    {

        let alertController = UIAlertController(title: "Alert", message: messageToDisplay, preferredStyle: .alert)

        

        let OKAction = UIAlertAction(title: "OK", style: .default) { (action:UIAlertAction!) in

            

            // Code in this block will trigger when OK button tapped.

            print("Ok button tapped");

            

        }

        

        alertController.addAction(OKAction)

        

        self.present(alertController, animated: true, completion:nil)

    }

    

    

}