NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: UIResponder.keyboardWillShowNotification, object: nil)

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: UIResponder.keyboardWillHideNotification, object: nil)

@objc func keyboardWillShow(notification:Notification){

        let userinfo:Dictionary = notification.userInfo!

        let frame = (userinfo[UIResponder.keyboardFrameEndUserInfoKey] as! NSValue).cgRectValue

        UIView.animate(withDuration: 0.4, animations: {

            self.view.frame.origin.y = 0 - frame.height

        })

    }

    @objc func keyboardWillHide(notification:Notification){

        UIView.animate(withDuration: 0.4, animations: {

            self.view.frame.origin.y = 0

        })

    }

NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillShowNotification, object: nil)

        NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillHideNotification, object: nil)