// 主activity
class BottomNavigationActivity : AppCompatActivity() {
    private lateinit var binding: ActivityBottomNavigationBinding

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_bottom_navigation)
        // 初始化 binding
        binding = ActivityBottomNavigationBinding.inflate(layoutInflater)

//        val control = findNavController(R.id.nav_host_fragment)
//        NavigationUI.setupWithNavController(binding.bottomNavigation, control)

        val navHostFragment =
            supportFragmentManager.findFragmentById(R.id.nav_host_fragment) as NavHostFragment
        binding.bottomNavigation.setupWithNavController(navHostFragment.navController)
        Log.d("BottomNavigationActivity", "navHostFragment: ${navHostFragment.navController}")
    }
}

// 页面布局
<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".demo11.BottomNavigationActivity">

    <!-- Fragment 容器：使用 FragmentContainerView -->
    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/nav_host_fragment"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@id/bottom_navigation"
        app:defaultNavHost="true"
        app:navGraph="@navigation/mobile_navigation" />

    <!-- 底部导航栏 -->
    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/bottom_navigation"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        app:labelVisibilityMode="labeled"
        app:layout_constraintBottom_toBottomOf="parent"
        app:menu="@menu/bottom_nav_menu" />
</androidx.constraintlayout.widget.ConstraintLayout>

// nav_Graph.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/nav_artist">

    <fragment
        android:id="@+id/nav_artist"
        android:name="com.example.myapplication.demo11.ArtistFragment"
        android:label="fragment_artist"
        tools:layout="@layout/fragment_artist" />

    <fragment
        android:id="@+id/nav_album"
        android:name="com.example.myapplication.demo11.AlbumFragment"
        android:label="fragment_album"
        tools:layout="@layout/fragment_album" />

    <fragment
        android:id="@+id/nav_pause"
        android:name="com.example.myapplication.demo11.PauseFragment"
        android:label="fragment_pause"
        tools:layout="@layout/fragment_pause" />
</navigation>

// menu.xml
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/nav_artist"
        android:icon="@drawable/icon_artist"
        android:title="艺术家" />
    <item
        android:id="@+id/nav_album"
        android:icon="@drawable/icon_album"
        android:title="专辑" />
    <item
        android:id="@+id/nav_pause"
        android:icon="@drawable/icon_pause"
        android:title="暂停" />
</menu>