class WelcomeFragment : Fragment() {

    override fun onCreateView(inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?): View? {
        // Inflate the layout for this fragment
        val view =  inflater.inflate(R.layout.fragment_welcome,
            container, false)
        val startButton = view.findViewById<Button>(R.id.btn_start)
        startButton.setOnClickListener {
            // Code that runs when the button is clicked
            view.findNavController( ).
                navigate(R.id.action_welcomeFragment_to_messageFragment)
        }
        return view
    }
}