A customised UIAlertController for reset password functionality written in Swift.

ResetPasswordAlert.swift

//
//  ResetPasswordAlert.swift
//
//  Created by Kalpesh on 06/05/19.
//  Copyright © 2019 Kalpesh Talkar. All rights reserved.
//
// For support: https://gist.github.com/KalpeshTalkar/1f8078f0e9340125f24102fdd4c73a82

import UIKit

/// Default title of the alert view.
fileprivate let TITLE = "Forgot your password?"

/// Default message of the alert view.
fileprivate let MESSAGE = "Enter your registererd e-mail address and we'll send a link to reset your password."

/// ResetPasswordAlert is a UIAlertController sub class customised to show reset password alert with a text field to enter email with submit and cancel buttons.The class requires Strin extension and UITextField extension to validate the email address.
public class ResetPasswordAlert: UIAlertController {


    /// Handler called when submit button is clicked.
    public typealias ResetPasswordHandler = ((String) -> Void)


    /// Submit action button.
    private var submitAction = UIAlertAction()


    /// Private init method.
    ///
    /// - Parameters:
    ///   - nibNameOrNil: Xib name. Optional parameter.
    ///   - nibBundleOrNil: Bundle of the xib. Optional parameter.
    private override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
    }


    /// Required init method.
    ///
    /// - Parameter aDecoder: NSCoder.
    internal required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }


    /// Init ResetPasswordAlert.
    ///
    /// - Parameters:
    ///   - title: Title for the alert.
    ///   - message: Message for the alert.
    ///   - handler: Handler called when submit button is clicked with entered email as parameter.
    //public convenience init(title: String = TITLE, message: String = MESSAGE, handler: ResetPasswordHandler? = nil) {
    public convenience init(title: String? = nil, message: String? = nil, handler: ResetPasswordHandler? = nil) {
        let ttl = title ?? TITLE
        let msg = message ?? MESSAGE
        self.init(title: ttl, message: msg, preferredStyle: .alert)
        submitAction = UIAlertAction(title: "Submit", style: .default) { (action) in
            if handler != nil {
                if let textField = self.textFields?[0] {
                    handler?(textField.text ?? "")
                }
            }
        }
        submitAction.isEnabled = false
        addAction(UIAlertAction(title: "Cancel", style: .destructive, handler: nil))
        addAction(submitAction)
        addTextField { (textField) in
            textField.textContentType = .emailAddress
            textField.addTarget(self, action: #selector(self.textFieldTextChanged(textField:)), for: .editingChanged)
        }
    }


    /// Method to handle text change.
    /// The methods enables the submit button if the entered email is valid.
    ///
    /// - Parameter textField: UITextField reference.
    @objc internal func textFieldTextChanged(textField: UITextField) {
        submitAction.isEnabled = textField.hasValidEmail()
    }


    /// Show ResetPasswordAlert.
    ///
    /// - Parameters:
    ///   - vc: UIViewController reference in which the alert is to be presented.
    ///   - completion: Completion block called after presenting the alert.
    public func present(in vc: UIViewController, completion: (() -> Void)? = nil) {
        vc.present(self, animated: true, completion: completion)
    }

}

Usage:

let pwdResetAlert = ResetPasswordAlert() { (email) in
    print("Email: \(email)")
}
present(pwdResetAlert, animated: true, completion: nil)

OR

ResetPasswordAlert(handler: { (email) in
    print("Email: \(email)")
}).present(in: self)

You can also set your custom title and message like below:

let pwdResetAlert = ResetPasswordAlert(title: "My Title", message: "My Message") { (email) in
    print("Email: \(email)")
}
present(pwdResetAlert, animated: true, completion: nil)

OR

ResetPasswordAlert(title: "My Title", message: "My Message", handler: { (email) in
    print("Email: \(email)")
}).present(in: self)