Xcode 8.3.3: How to Remember Username and Password and Add Touch-ID Authentication - ios

Question

My current project has a login page, but I find that the user must enter their username and password again when they log in. How do I make it easier for them, by implementing "remember username and password" functionality and adding Touch ID?
My code is as follows:
import UIKit
import Firebase
class LoginViewController: UIViewController {
var imageView: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
imageView = UIImageView(frame: view.bounds)
imageView.contentMode = .scaleAspectFill
imageView.clipsToBounds = true
imageView.image = #imageLiteral(resourceName: "background")
imageView.center = view.center
view.addSubview(imageView)
self.view.sendSubview(toBack: imageView)
}
//Outlets
#IBOutlet weak var emailTextField: UITextField!
#IBOutlet weak var passwordTextField: UITextField!
//Login Action
#IBAction func loginAction(_ sender: AnyObject) {
if self.emailTextField.text == "" || self.passwordTextField.text == "" {
//Alert to tell the user that there was an error because they didn't fill anything in the textfields because they didn't fill anything in
let alertController = UIAlertController(title: "Error", message: "Please enter an email and password.", preferredStyle: .alert)
let defaultAction = UIAlertAction(title: "OK", style: .cancel, handler: nil)
alertController.addAction(defaultAction)
self.present(alertController, animated: true, completion: nil)
} else {
Auth.auth().signIn(withEmail: self.emailTextField.text!, password: self.passwordTextField.text!) { (user, error) in
if error == nil {
//Print into the console if successfully logged in
print("You have successfully logged in")
//Go to the HomeViewController if the login is sucessful
let vc = self.storyboard?.instantiateViewController(withIdentifier: "Home")
self.present(vc!, animated: true, completion: nil)
} else {
//Tells the user that there is an error and then gets firebase to tell them the error
let alertController = UIAlertController(title: "Error", message: error?.localizedDescription, preferredStyle: .alert)
let defaultAction = UIAlertAction(title: "OK", style: .cancel, handler: nil)
alertController.addAction(defaultAction)
self.present(alertController, animated: true, completion: nil)
}
}
}
}

Answer 1

you have a couple of ways to save your user Credentials. Most common way is to save those in Keychain.
KeyChain Swift
After that you can user your touchID authentication, by calling the default methods to implement this. Here is a nice tutorial how you should do it:
Touch ID for Local Authentication