Email address validation in swift

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Email address validation in swift

Introduction to email address validation in swift

In this tutorial, we will learn how to add email address validation in swift4. We will use NSPredicate with regex to validate email of format “xxx@xx.xxx”. Also, how to validate an empty UITextField in swift using guard statement. Let us jump to the tutorial and learn how to validate email address  and check for empty UITextFields in swift.

Steps to add email validation in swift

Creating user interface for the app

Step 1: Open up Xcode and select “Single View App” template, name it “ValidationsAndEmailValidation“.

Step 2: Open “Main.storyboard” as we are going to create user interface as shown in given below picture

Email validation in swift

Step 3: Drag UILabel to view as we want to display validation message to user if inputs failed to validate email address or if UITextFields are empty i.e empty UITextField validation and add constraints as shown below

Email address validation in swift

Step 4: Drag UITextField for Email address to be entered by user and add constraints as shown below

Email address validation in swift


Step 5: Drag UITextField for password to be entered by user and add constraints as shown below

UITextField-password-constraint-Email validation in swift

Step 6: Drag UIButton so that we can validate the values inputted by user when he tap on button and add constraints as shown below

email validation in swift

Step 7: As of now we are done with our user interface design and if you run your app, you will see its nicely comes up on iPhone simulator screen.

Coding for email validation


Step 8: Open “ViewController.swift” and create IBOutlet for two UITextFields, UILabel and IBAction for our UIButton.

//
// ViewController.swift
// ValidationsAndEmailValidation
//
// Created by Aman Aggarwal on 26/01/18.
// Copyright © 2018 Aman Aggarwal. All rights reserved.
//
import UIKit
class ViewController: UIViewController {
@IBOutlet weak var txtEmail: UITextField!
@IBOutlet weak var txtPassword: UITextField!
@IBOutlet weak var lblValidationMessage: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
}
//MARK:- loginUser
@IBAction func loginUser(_ sender: Any) {
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
view raw ViewController-Validation-emailaddress-UITextFields.swift hosted with ❤ by GitHub

Step 9: Open “Main.storyboard” and connect IBOutlets created in step 8 to UILabel and UITextFields. Connect IBAction to “touchupinside” event of UIButton.

Step 10: Now in viewDidLoad function set “lblValidationMessage” to hidden as we did not want to show any message until user tap on UIButton.

//
// ViewController.swift
// ValidationsAndEmailValidation
//
// Created by Aman Aggarwal on 26/01/18.
// Copyright © 2018 Aman Aggarwal. All rights reserved.
//
import UIKit
class ViewController: UIViewController {
@IBOutlet weak var txtEmail: UITextField!
@IBOutlet weak var txtPassword: UITextField!
@IBOutlet weak var lblValidationMessage: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
lblValidationMessage.isHidden = true
}
//MARK:- loginUser
@IBAction func loginUser(_ sender: Any) {
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
view raw ViewController-Validation-emailaddress-UITextFields-1.swift hosted with ❤ by GitHub

Step 11: We will create another function named “isValidEmail“, accepting email as parameter and return TRUE or FALSE based upon email validation using regex and NSPredicate.
func isValidEmail(emailID:String) -> Bool {
let emailRegEx = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}"
let emailTest = NSPredicate(format:"SELF MATCHES %@", emailRegEx)
return emailTest.evaluate(with: emailID)
}
view raw EmailValidationscript.swift hosted with ❤ by GitHub


Step 12: In our “loginUser” IBAction, we will call the above script and validate our email typed in “txtEmail” UITextField. Also we will use “guard” statement to check whether our UITextFields contains any value or are empty. If empty then we will show validation message in “lblValidationMessage” UILabel.

//MARK:- loginUser
@IBAction func loginUser(_ sender: Any) {
lblValidationMessage.isHidden = true
guard let email = txtEmail.text, txtEmail.text?.characters.count != 0 else {
lblValidationMessage.isHidden = false
lblValidationMessage.text = "Please enter your email"
return
}
if isValidEmail(emailID: email) == false {
lblValidationMessage.isHidden = false
lblValidationMessage.text = "Please enter valid email address"
}
guard let password = txtPassword.text, txtPassword.text?.characters.count != 0 else {
lblValidationMessage.isHidden = false
lblValidationMessage.text = "Please enter your password"
return
}
}
view raw ViewController-Validation-emailaddress-UITextFields-2.swift hosted with ❤ by GitHub

Step 13: Run your app and you will see the validations are working.

Complete Code:

//
// ViewController.swift
// ValidationsAndEmailValidation
//
// Created by Aman Aggarwal on 26/01/18.
// Copyright © 2018 Aman Aggarwal. All rights reserved.
//
import UIKit
class ViewController: UIViewController {
@IBOutlet weak var txtEmail: UITextField!
@IBOutlet weak var txtPassword: UITextField!
@IBOutlet weak var lblValidationMessage: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
lblValidationMessage.isHidden = true
}
//MARK:- loginUser
@IBAction func loginUser(_ sender: Any) {
lblValidationMessage.isHidden = true
guard let email = txtEmail.text, txtEmail.text?.characters.count != 0 else {
lblValidationMessage.isHidden = false
lblValidationMessage.text = "Please enter your email"
return
}
if isValidEmail(emailID: email) == false {
lblValidationMessage.isHidden = false
lblValidationMessage.text = "Please enter valid email address"
}
guard let password = txtPassword.text, txtPassword.text?.characters.count != 0 else {
lblValidationMessage.isHidden = false
lblValidationMessage.text = "Please enter your password"
return
}
}
func isValidEmail(emailID:String) -> Bool {
let emailRegEx = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}"
let emailTest = NSPredicate(format:"SELF MATCHES %@", emailRegEx)
return emailTest.evaluate(with: emailID)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
view raw ViewController-Validation-emailaddress-UITextFields-3.swift hosted with ❤ by GitHub

Where to go from here:

We learned how to validate email address in swift. Also  we learned to validate empty UITextField using guard statement in swift. Download the source code from here.