backstack with navigation component

using the navigation component on two fragments, my app currently destroys a fragment when navigateUp() is called (using the setupActionBarWithNavController()), and therefore when I enter the deleted fragment, all progress is lost, I am trying to change that my adding the fragment to a backstack (and only one instance of the fragment) but I've been struggling with that...

Here's some code:

MainActivity:

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

        loginRepository = LoginRepository()
        if (!loginRepository.checkLoggedInState()) {
            goToLoginActivity()
        }

        Log.d("FirebaseMain", "onCreate: ${loginRepository.checkLoggedInState()}")

        //MyApplication.app.currentUser
        binding = DataBindingUtil.setContentView(this, R.layout.activity_main)

        navController = Navigation.findNavController(this, R.id.nav_host_fragment)

        // setup custom action bar
        setSupportActionBar(findViewById(R.id.toolbar))

        // adds a return button in the ActionBar.
        NavigationUI.setupActionBarWithNavController(this, navController)
    }

FormFragment:

(the fragment I want to save its progress and add to backstack)

class FormFragment : Fragment() {

    private lateinit var binding: FragmentFormBinding

    private val checkListRecyclerAdapter = CheckListRecyclerAdapter(
        hashMapOf(
            0 to "mirrors",
            1 to "blinkers1",
            2 to "blinkers11",
            3 to "blin4kers",
            4 to "blink3e1123rs",
            5 to "blink6ers",
            6 to "blin53kers",
            7 to "blin8kers",
            8 to "blin7kers",
            9 to "blin43kers",
            10 to "blin32kers",
            11 to "blin322kers",

            )
    )

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

    }

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {

        binding = DataBindingUtil.inflate(inflater, R.layout.fragment_form, container, false)

        binding.rvCheckList.apply {
            // this is used to load the data sequentially from top to bottom,
            this.layoutManager = LinearLayoutManager(context)

            // the adapter that loads the data into the list
            this.adapter = checkListRecyclerAdapter
        }

        return binding.root
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

    }

}

Thanks in advance for any help!

I've been struggling with some similar to this. Fragments in Navigation Component doesnt keep their state. If you keep your data progress while navigate, you need create a SharedViewModel scoped to a Navigation Graph.

In Fragment:

private val navGraphScopedViewModel by navGraphViewModels<NavGraphViewModel>(R.id.your_nav_graph)

Create this class:

class NavGraphViewModel : ViewModel() {
    var sharedData=  CustomObject()
}

And from all your fragments you can access and set data:

 val data = navGraphScopedViewModel.sharedData

I hope I've helped you