Moving button up when keyboard is enabled

This is the code i wrote to move the button up when the keyboard is enabled:

@IBOutlet var lastNameText: HoshiTextField! 
@IBOutlet var firstNameText: HoshiTextField!

override func viewDidLoad() {      
        var fab = MDCFloatingButton()
        fab.translatesAutoresizingMaskIntoConstraints = false
        fab.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant:-30.0).isActive = true
        fab.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant:-240.0).isActive = true
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name:.UIKeyboardWillShow, object: nil )
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name:.UIKeyboardWillHide, object: nil)

        @objc func keyboardWillShow(notificaion: NSNotification) {
            if let keyboardSize = (notificaion.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue{
                //fab = UIButton(frame: CGRect(10+20, self.view.frame.size.height - keyboardSize.height - 40,80,30))     
                fab.frame = CGRect(x: 320, y: 350, width: 60, height: 60)    
        }       
 }

@objc func keyboardWillHide(notification: NSNotification ) {
    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue{
        fab.frame = CGRect(x: 320, y: 350, width: 65, height: 65)
    }
}

Please give input.

First add the textfield delegate method in your class after that simply put this code and change it according to you :-

func textFieldDidBeginEditing(_ textField: UITextField) {
    switch textField {
    case txtFldSponsorID:
        moveTextfield(textfield: txtFldSponsorID, moveDistance: 0, up: true)
    case txtFldFullName:
        moveTextfield(textfield: txtFldFullName, moveDistance: -10, up: true)
    case txtFldEmail:
        moveTextfield(textfield: txtFldEmail, moveDistance: -10, up: true)
    case txtFldMobile:
        moveTextfield(textfield: txtFldMobile, moveDistance: -10, up: true)
    case txtFldAddress:
        moveTextfield(textfield: txtFldAddress, moveDistance: -80, up: true)
    case txtFldCity:
        moveTextfield(textfield: txtFldCity, moveDistance: -80, up: true)
    default:
        break
    }
}

func textFieldDidEndEditing(_ textField: UITextField) {
    switch textField {
    case txtFldSponsorID:
        moveTextfield(textfield: txtFldSponsorID, moveDistance: 0, up: true)
    case txtFldFullName:
        moveTextfield(textfield: txtFldFullName, moveDistance: 10, up: true)
    case txtFldEmail:
        moveTextfield(textfield: txtFldEmail, moveDistance: 10, up: true)
    case txtFldMobile:
        moveTextfield(textfield: txtFldMobile, moveDistance: 10, up: true)
    case txtFldAddress:
        moveTextfield(textfield: txtFldAddress, moveDistance: 80, up: true)
    case txtFldCity:
        moveTextfield(textfield: txtFldCity, moveDistance: 80, up: true)
    default:
        break
    }
}