android - 运行时错误：java.lang.RuntimeException：无法启动活动 ComponentInfo

Question

运行此代码时，我的应用程序在运行时崩溃setupActionBarWithNavController(findNavController(R.id.fragmentContainerView))

我正在尝试添加菜单栏，但应用程序不断崩溃。

我不明白这里是我的文件的原因，如果需要添加更多文件，请告诉我

主要活动

package com.example.todoappcbpractice2

import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.Menu
import android.view.MenuItem
import androidx.navigation.findNavController
import androidx.navigation.ui.setupActionBarWithNavController
import kotlinx.android.synthetic.main.fragment_list.*

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

        setupActionBarWithNavController(findNavController(R.id.fragmentContainerView))      //---App crashed here

    }


}

ActivityMain.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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/fragmentContainerView"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="0dp"
        android:layout_height="729dp"
        android:layout_marginStart="1dp"
        android:layout_marginLeft="1dp"
        android:layout_marginEnd="1dp"
        android:layout_marginRight="1dp"
        app:defaultNavHost="true"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:navGraph="@navigation/my_nav" />
</androidx.constraintlayout.widget.ConstraintLayout>

片段列表.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/idFragmentList"
    android:name="androidx.navigation.fragment.my_nav"
    tools:context=".fragments.list.ListFragment">


    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:listitem="@layout/item_todo" />

    <com.google.android.material.floatingactionbutton.FloatingActionButton
        android:id="@+id/addBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentBottom="true"
        android:layout_marginStart="32dp"
        android:layout_marginLeft="32dp"
        android:layout_marginTop="32dp"
        android:layout_marginEnd="32dp"
        android:layout_marginRight="32dp"
        android:layout_marginBottom="32dp"
        android:src="@drawable/ic_baseline_add_24" />


</RelativeLayout>

错误日志

2021-05-21 17:39:35.550 9535-9535/com.example.todoappcbpractice2 E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.todoappcbpractice2, PID: 9535
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.todoappcbpractice2/com.example.todoappcbpractice2.MainActivity}: java.lang.IllegalStateException: Activity com.example.todoappcbpractice2.MainActivity@8b7265a does not have a NavController set on 2131230896
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3310)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3459)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2046)
        at android.os.Handler.dispatchMessage(Handler.java:107)
        at android.os.Looper.loop(Looper.java:225)
        at android.app.ActivityThread.main(ActivityThread.java:7564)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:539)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)
     Caused by: java.lang.IllegalStateException: Activity com.example.todoappcbpractice2.MainActivity@8b7265a does not have a NavController set on 2131230896
        at androidx.navigation.Navigation.findNavController(Navigation.java:61)
        at androidx.navigation.ActivityKt.findNavController(Activity.kt:30)
        at com.example.todoappcbpractice2.MainActivity.onCreate(MainActivity.kt:17)
        at android.app.Activity.performCreate(Activity.java:7916)
        at android.app.Activity.performCreate(Activity.java:7903)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1307)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3285)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3459) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2046) 
        at android.os.Handler.dispatchMessage(Handler.java:107) 
        at android.os.Looper.loop(Looper.java:225) 
        at android.app.ActivityThread.main(ActivityThread.java:7564) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:539) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950) 

我是 Kotlin Android Dev 的新手，所以请告诉我任何改进建议。

标签： androidandroid-studiokotlinruntime