How to use navigation component in fragment Android

Issue

I want to use Navigation component in my fragment.

My XML code like this

 <androidx.constraintlayout.widget.ConstraintLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    ...

    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/fragment_nav_host_home"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:defaultNavHost="true"
        app:navGraph="@navigation/home_navigation"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/app_bar" />
</androidx.constraintlayout.widget.ConstraintLayout>

And Initializing navigation code like this.

class HomeFragment : Fragment() {

   //...initialie view


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

        val navController = Navigation.findNavController(binding.fragmentNavHostHome)
        navController.setGraph(R.navigation.home_navigation)

        val appBarConfiguration = AppBarConfiguration(navController.graph)

        NavigationUI.setupActionBarWithNavController(requireActivity() as AppCompatActivity, navController, appBarConfiguration)

    
    }

}

And after I launched my app, I got an error message like this.

View androidx.fragment.app.FragmentContainerView{... app:id/fragment_nav_host_home} does not have a NavController set

Also, findNavController() does not work.

How can I use navigation component in my fragment

Solution

Kotlin Answer

Key point is that try to use childFragmentManager in onViewCreated() function.

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

  // Define container.
  val loginDialogContainer = childFragmentManager.findFragmentById(R.id.container) as NavHostFragment

  // Set nav controller.
  val loginNavController: NavController = loginDialogContainer.navController
}

Answered By - DevPolarBear