Currently doing the fragments and navigation pathway of the android kotlin course and having some troubles with the letter list fragment

Question

When I populate the nav_graph.xml with the two fragments the words fragment displays fine but the letters fragment just displays a default item list of 1 to 9. Below is the letter fragment for closer inspection. If you find yourself in need of anymore infromation please ask me as I would really like to get this problem resolved.

/**
 * A simple [Fragment] subclass.
 * Use the [LetterListFragment.newInstance] factory method to
 * create an instance of this fragment.
 */
class LetterListFragment : Fragment() {

       private var _binding: FragmentLetterListBinding? = null
       private val binding get() = _binding!!
       private lateinit var recyclerView: RecyclerView
       private var isLinearLayoutManager = true




       override fun onCreate(savedInstanceState: Bundle?) {
           super.onCreate(savedInstanceState)
        setHasOptionsMenu(true)
       }


       override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
       ): View? {
        _binding = FragmentLetterListBinding.inflate(inflater, container, false)
        val view = binding.root
        return view }



       override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        recyclerView = binding.recyclerView
        chooseLayout()
       }

        override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {
        inflater.inflate(R.menu.layout_menu, menu)

        val layoutButton = menu.findItem(R.id.action_switch_layout)
        setIcon(layoutButton)
       }


       private fun chooseLayout() {
        when (isLinearLayoutManager) {
            true -> {
                recyclerView.layoutManager = LinearLayoutManager(context)
                recyclerView.adapter = LetterAdapter()
            }
            false -> {
                recyclerView.layoutManager = GridLayoutManager(context, 4)
                recyclerView.adapter = LetterAdapter()
            }
        }
       }

       private fun setIcon(menuItem: MenuItem?) {
        if (menuItem == null)
            return

        menuItem.icon =
            if (isLinearLayoutManager)
                ContextCompat.getDrawable(this.requireContext(), R.drawable.ic_grid_layout)
            else ContextCompat.getDrawable(this.requireContext(), R.drawable.ic_linear_layout)
       }

       override fun onOptionsItemSelected(item: MenuItem): Boolean {
        return when (item.itemId) {
            R.id.action_switch_layout -> {
                isLinearLayoutManager = !isLinearLayoutManager
                chooseLayout()
                setIcon(item)

                return true
            }

            else -> super.onOptionsItemSelected(item)
        }
       }



       override fun onDestroyView() {
        super.onDestroyView()
        _binding = null
       }


}