您可以使用Jet pack Navigation组件中的底部导航视图实现来完成这项工作。它简单明了。底部导航将默认处理所有项目选定的用例。您也可以轻松地自定义它。这里我添加了底部导航设置的Kotlin示例。第01步：将以下依赖项添加到您的应用的build.gradle文件：

dependencies {
  val nav_version = "2.4.2"

  // Java language implementation
  implementation("androidx.navigation:navigation-fragment:$nav_version")
  implementation("androidx.navigation:navigation-ui:$nav_version")

  // Kotlin
  implementation("androidx.navigation:navigation-fragment-ktx:$nav_version")
  implementation("androidx.navigation:navigation-ui-ktx:$nav_version")

}

步骤02：通过XML添加NavHostFragment作为应用的主Activity的一部分：

<?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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

   <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_navigation_menu" />

<fragment
    android:id="@+id/nav_host_fragment_activity_main"
    android:name="androidx.navigation.fragment.NavHostFragment"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    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/main_nav_graph" />
</androidx.constraintlayout.widget.ConstraintLayout>

步骤03：初始化你的main main activity的底部导航视图和导航控制器OnCreate（）

override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(LayoutInflater.from(this))
        setContentView(binding.root)
        val navView : BottomNavigationView = binding.navView
        val navController = findNavController(R.id.nav_host_fragment_activity_main)
        navView.setupWithNavController(navController)
     
       // Get bottom nav listener
        navController.addOnDestinationChangedListener 
        { _, destination, _ ->
            when (destination.id) {
                R.id.A_Fragment -> {
                    // Add your requirement here base with destination
                }
                else -> {
                    // Add your requirement here
                }
            }

            // Manage bottom nav visibility and etc
            if (destination.id in arrayOf(
                    R.id.A_Fragment,
                    R.id.B_Fragment,
                    R.id.C_Fragment
            )) {
                navView.visibility = View.VISIBLE
                this.supportActionBar?.show()
                setupToolbar()
            }
            else {
                navView.visibility = View.GONE
                this.supportActionBar?.hide()
                // No Toolbar

            }
        }

}

您还可以使用此实现定义带有导航图的目标。如果您需要添加或自定义bottomNaivationView项目徽章，您可以使用以下示例fun：

private fun setupBadge(bottomNavigationView: BottomNavigationView) {
        val menu: Menu = bottomNavigationView.menu
        val your_A_MenuItem: MenuItem = menu.getItem(1)
        val your_B_MenuItem: MenuItem = menu.getItem(2)
        val your_A_Badge = bottomNavigationView.getOrCreateBadge(your_A_MenuItem.itemId)
      
        val your_B_Badge = bottomNavigationView.getOrCreateBadge(your_B_MenuItem.itemId)
// Add numbers
your_A_Badge.number = 10
your_A_Badge.isVisible = true
        
    }