MediumFragment.kt

@AndroidEntryPoint
class MediumFragment : Fragment(R.layout.fragment_medium) {

    private val navigation: NavController by lazy {
        findNavController()
    }
    
    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        observeNavigationCallBack()
    }
    
    
    private fun observeNavigationCallBack() {
        navigation.currentBackStackEntry?.savedStateHandle?.getLiveData<Boolean>("key")
            ?.observe(viewLifecycleOwner) {
                Log.d(TAG, it.toString())
            }
    }
}