BottomNavigationView items not highlighted on back press

Question

I'm using BottomNavigationView with Navigation component. When I click the back button, the Fragment stack is correctly handled, but the BottomNavigationView doesn't change and stays blocked on the last state.

I made sure to have the same ids in my nav_graph and the BottomNavigationView's items.

My nav_graph.xml:

<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/nav_graph"
    app:startDestination="@id/journalFragment">

    <fragment
        android:id="@+id/journalFragment"
        android:name="com.example.Fragment1"
        android:label="@string/navigation_title_journal"
        tools:layout="@layout/fragment_journal"/>
    <fragment
        android:id="@+id/toolsFragment"
        android:name="com.example.Fragment2"
        android:label="@string/navigation_title_tools"
        tools:layout="@layout/fragment_tools" />
</navigation>

My bottom_navigation_menu:

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/journalFragment"
        android:enabled="true"
        android:title="@string/navigation_title_journal" /> 
    <item
        android:id="@+id/toolsFragment"
        android:enabled="true"
        android:title="@string/navigation_title_tools" /> 
</menu>

In MainActivity's onCreate():

NavHostFragment navHostFragment =
                (NavHostFragment) getSupportFragmentManager().findFragmentById(R.id.nav_host_container);

        navController = navHostFragment.getNavController();

        appBarConfiguration = new AppBarConfiguration.Builder(
                R.id.journalFragment, R.id.toolsFragment).build();

        setupWithNavController(mToolbar, navController, appBarConfiguration);

        bottomNavigationView.setOnItemSelectedListener(item -> {
            Log.d("MainActivity", "setOnItemSelectedListener-------");
            switch (item.getItemId()) {
                case R.id.dreamJournalFragment -> navController.navigate(R.id.dreamJournalFragment);
                case R.id.statisticsFragment -> navController.navigate(R.id.statisticsFragment);
                case R.id.toolsFragment -> navController.navigate(R.id.toolsFragment);
                case R.id.wikiFragment -> navController.navigate(R.id.wikiFragment);
            }
            return true;
        });

        bottomNavigationView.setOnItemReselectedListener(item -> {
            // Ignore
        });

In activity_main:

 <androidx.fragment.app.FragmentContainerView
                android:id="@+id/nav_host_container"
                android:name="androidx.navigation.fragment.NavHostFragment"
                android:layout_width="match_parent"
                android:layout_height="0dp"
                android:layout_weight="1"
                app:defaultNavHost="true"
                app:navGraph="@navigation/nav_graph" />

            <com.google.android.material.bottomnavigation.BottomNavigationView
                android:id="@+id/bottom_navigation"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                app:menu="@menu/bottom_navigation_menu" />

Answer 1

You haven't connected the navigation controller to the bottom navigation view. To resolve this, you can include the following code:

bottomNavigationView.setupWithNavController(navController)