BottomNavigationBar not working properly after navigate to navigation fragment by cutom button click

Question

Take a Bottom Navigation activity from android studio template. there are 3 fragment with 3 item in BottomNavBar (HomeFragment, DashboardFragment, NotificationsFragment) navigate to DashboardFragment from HomeFragment by a button click. after that home item click from BottomNavBar should open Homefragment. But not working as expected.

• Go to DashboardFrament from HomeFrament by

        textView.setOnClickListener {
            findNavController().navigate(R.id.navigation_dashboard)
        }

MainActivity.kt

class MainActivity : AppCompatActivity() {

    private lateinit var binding: ActivityMainBinding

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

        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        val navView: BottomNavigationView = binding.navView

        val navController = findNavController(R.id.nav_host_fragment_activity_main)

        navView.setupWithNavController(navController)
    }
}

main_activity.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingTop="?attr/actionBarSize">

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/nav_view"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="0dp"
        android:layout_marginEnd="0dp"
        android:background="?android:attr/windowBackground"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:menu="@menu/bottom_nav_menu" />

    <fragment
        android:id="@+id/nav_host_fragment_activity_main"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:defaultNavHost="true"
        app:layout_constraintBottom_toTopOf="@id/nav_view"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:navGraph="@navigation/mobile_navigation" />

</androidx.constraintlayout.widget.ConstraintLayout>

HomeFramgent.kt

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

        val textView: TextView = view.findViewById(R.id.text_home)
        textView.setOnClickListener {
            findNavController().navigate(R.id.navigation_dashboard)
        }
    }

navigation.xml

<?xml version="1.0" encoding="utf-8"?>
<navigation xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/mobile_navigation"
    app:startDestination="@+id/navigation_home">

    <fragment
        android:id="@+id/navigation_home"
        android:name="com.app.bottomnav.ui.home.HomeFragment"
        android:label="@string/title_home"
        tools:layout="@layout/fragment_home" />

    <fragment
        android:id="@+id/navigation_dashboard"
        android:name="com.app.bottomnav.ui.dashboard.DashboardFragment"
        android:label="@string/title_dashboard"
        tools:layout="@layout/fragment_dashboard" />

    <fragment
        android:id="@+id/navigation_notifications"
        android:name="com.app.bottomnav.ui.notifications.NotificationsFragment"
        android:label="@string/title_notifications"
        tools:layout="@layout/fragment_notifications" />
</navigation>

Answer 1

Whenever you are navigating to any root destination from another fragment, you should have to clear the previous stack using popUpTo option builder.

Update your code navigation code in your home fragment.

findNavController()
    .navigate(R.id.navigation_dashboard,
            null,
            NavOptions.Builder()
               .setPopUpTo(R.id.navigation_home, true)
               .build()
)

Answer 2

HomeFragment

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

    val textView: TextView = view.findViewById(R.id.text_home)
    textView.setOnClickListener {
       /**
       * replace this line
       */
       // findNavController().navigate(R.id.navigation_dashboard)
       val mainActivity = (requiredActivity() as MainActivity)
       mainActivity.binding.navView.selectedItemId = R.id.navigation_dashboard
    }
}