BaseViewController for iOS Swift to handle keyboard overlapping important views and easier translations between view controllers(IMHO)

BaseVC.swift

//
//  BaseVC.swift
//
//  Created by Simon on 4/23/17.
//  Copyright © 2017 Simon. All rights reserved.
//

import UIKit

/*
 Paste here your format which you use 
 to identify StoryboardID for your VCs(View Controllers)
 I recomend using StoryboardID which are the same as
 naming of the class it uses
 Paste '%@' where you have a real name of VC
 For example if you have VCs named as:
    TMLoginVC, TMRegisterVC, TMMenuVC
    then you should use "TM%@VC" as your VCFormat
 */
let VCFormat = "%@VC"

/*
 List here all VCs' real names which you want to show from code
 this name will be used with the VCFormat to constract a StoryboardID
 */
enum VCs: String {
    case Menu = "Menu"
}

class BaseVC: UIViewController, UITextFieldDelegate, UITextViewDelegate {
    private var currentTextField: UIView?
/*
    Assgin all textFields' and textViews' delegates
    to viewController that inherits from the BaseVC
 */
/*
     Connect this constraint to a content view's top
     to move all your content up when a keyboard appears
 */
    @IBOutlet weak var contentTopSpaceConstraint: NSLayoutConstraint?
    private var initialTopSpace: CGFloat?
    private var keyboardNotification: NSNotification?
    
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        self.initialTopSpace = self.contentTopSpaceConstraint?.constant
        let tap = UITapGestureRecognizer.init(target: self, action: #selector(resignCurrentTextField))
        view.addGestureRecognizer(tap)
    }
    
    deinit {
        NotificationCenter.default.removeObserver(self)
    }
    
    func getViewController(viewController: VCs) -> UIViewController {
        let viewControllerName = String(format: VCFormat, viewController.rawValue)
        return (storyboard?.instantiateViewController(withIdentifier: viewControllerName))!
    }
    
    func animateLayoutWithDuration(duration: Double, options: UIViewAnimationOptions) {
        UIView.animate(withDuration: duration, delay: 0.0, options: options, animations: {
            self.view.layoutIfNeeded()
        }, completion: nil)
    }
    
    // MARK: Keyboard handling
    
    @IBAction func resignCurrentTextField(sender: NSObject) {
        if currentTextField != nil {
            currentTextField?.resignFirstResponder()
        }
    }
    
    func registerForKeyboardEvents() {
        NotificationCenter.default.addObserver(self, selector: #selector(handleKeyboardNotification),
                                               name: .UIKeyboardWillHide, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(handleKeyboardNotification),
                                               name: .UIKeyboardWillShow, object: nil)
    }
    
    func handleKeyboardNotification(notification: NSNotification) {
        let keyboardRect = view.convert((notification.userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue, from: nil)
        let curve = (notification.userInfo![UIKeyboardAnimationCurveUserInfoKey] as! NSNumber).uintValue
        let duration = (notification.userInfo![UIKeyboardAnimationDurationUserInfoKey] as! NSNumber).doubleValue
        let animationCurveOption = curve << 16
        let textFieldFrame = view.convert((self.currentTextField?.frame)!, from: currentTextField?.superview)
        
        if notification.name == .UIKeyboardWillShow {
            let difference = textFieldFrame.maxY - keyboardRect.origin.y
            if difference > 0 {
                contentTopSpaceConstraint?.constant = self.initialTopSpace! - difference - 8.0
            }
            self.keyboardNotification = notification
        } else {
            contentTopSpaceConstraint?.constant = self.initialTopSpace!
            self.keyboardNotification = nil
        }
        
        animateLayoutWithDuration(duration: duration, options: UIViewAnimationOptions(rawValue: animationCurveOption))
    }
    
    func textFieldShouldBeginEditing(_ textField: UITextField) -> Bool {
        currentTextField = textField
        if keyboardNotification != nil {
            handleKeyboardNotification(notification: keyboardNotification!)
        }
        return true
    }
 
    func textViewShouldBeginEditing(_ textView: UITextView) -> Bool {
        currentTextField = textView
        if keyboardNotification != nil {
            handleKeyboardNotification(notification: keyboardNotification!)
        }
        return true
    }
}