使用Kotlin作为底部导航组件创建了一个应用程序，但启动后每次都会崩溃。

• • 主要活动**

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val bottomNav = findViewById<BottomNavigationView>(R.id.bottomNavigationView)
        val fragmentContainer = findViewById<View>(R.id.fragmentContainer)

        bottomNav.setupWithNavController(fragmentContainer.findNavController())
    }
}

• • 导航. 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/navigation"
    app:startDestination="@id/kotlinFragment">

    <fragment
        android:id="@+id/kotlinFragment"
        android:name="com.example.bottomnavigation.ui.KotlinFragment"
        android:label="fragment_kotlin"
        tools:layout="@layout/fragment_kotlin" />
    <fragment
        android:id="@+id/javaFragment"
        android:name="com.example.bottomnavigation.ui.JavaFragment"
        android:label="fragment_java"
        tools:layout="@layout/fragment_java" />
    <fragment
        android:id="@+id/flutterFragment"
        android:name="com.example.bottomnavigation.ui.FlutterFragment"
        android:label="fragment_flutter"
        tools:layout="@layout/fragment_flutter" />
</navigation>

• • 底部导航. xml**

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">

    <item
        android:title="@string/kotlin"
        android:id="@+id/kotlinFragment"
        android:icon="@drawable/code"/>
    <item
        android:title="@string/java"
        android:id="@+id/javaFragment"
        android:icon="@drawable/code"/>
    <item
        android:title="@string/flutter"
        android:id="@+id/flutterFragment"
        android:icon="@drawable/code"/>
</menu>

• • 崩溃后出错**

E/libc: Access denied finding property "ro.odm.prev.product.name"
I/Perf: Connecting to perf service.
E/Perf:  perftest packageName : com.example.bottomnavigation App is allowed to use Hide APIs  
D/NetworkSecurityConfig: No Network Security Config specified, using platform default
D/NetworkSecurityConfig: No Network Security Config specified, using platform default
E/libEGL: Invalid file path for libcolorx-loader.so
E/MultiApp.Impl: OplusMultiAppImpl
D/AppCompatDelegate: Checking for metadata for AppLocalesMetadataHolderService : Service not found
I/oplus.android.OplusFrameworkFactoryImpl: getOplusRedPacketManager
W/ottomnavigatio: Accessing hidden method Landroid/view/View;->computeFitSystemWindows(Landroid/graphics/Rect;Landroid/graphics/Rect;)Z (greylist, reflection, allowed)
W/ottomnavigatio: Accessing hidden method Landroid/view/ViewGroup;->makeOptionalFitsSystemWindows()V (greylist, reflection, allowed)
E/OplusCustomizeRestrictionManager: sInstance is null, start a new sInstance
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.bottomnavigation, PID: 9514
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.bottomnavigation/com.example.bottomnavigation.MainActivity}: java.lang.IllegalStateException: View androidx.fragment.app.FragmentContainerView{13e6350 V.E...... ......I. 0,0-0,0 #7f0800c5 app:id/fragmentContainer} does not have a NavController set
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3729)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3896)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:140)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:100)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2326)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:263)
        at android.app.ActivityThread.main(ActivityThread.java:8296)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:612)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1006)
     Caused by: java.lang.IllegalStateException: View androidx.fragment.app.FragmentContainerView{13e6350 V.E...... ......I. 0,0-0,0 #7f0800c5 app:id/fragmentContainer} does not have a NavController set
        at androidx.navigation.Navigation.findNavController(Navigation.kt:71)
        at androidx.navigation.ViewKt.findNavController(View.kt:28)
        at com.example.bottomnavigation.MainActivity.onCreate(MainActivity.kt:18)
        at android.app.Activity.performCreate(Activity.java:8153)
        at android.app.Activity.performCreate(Activity.java:8137)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1310)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3698)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3896) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:140) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:100) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2326) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:263) 
        at android.app.ActivityThread.main(ActivityThread.java:8296) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:612) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1006) 
I/Process: Sending signal. PID: 9514 SIG: 9

我做了3个菜单项"Kotlin"，"java"和"flutter"，使用底部导航在片段之间切换。使用Android Studio（Kotlin）创建应用程序