Kotlin-导航组件-无法从当前目的地找到导航动作/目的地 [英] Kotlin - Navigation Components - Navigation action/destination cannot be found from the current destination

问题描述

问题

java.lang.IllegalArgumentException: Navigation action/destination xxxx/action_scanFragment_to_addVehicleFragment cannot be found from the current destination xxxx/addVehicleFragment

当我这样做时会发生错误

The error occurs when I do

findNavController().navigate(R.id.action_scanFragment_to_addVehicleFragment)

在scanFragment中.这意味着当前目的地是addVehicleFragment，但应该是scanFragment.

in scanFragment. Which means that current destination is addVehicleFragment, but it should be scanFragment.

我对如何解决这个问题一无所知. 请参阅我先前的问题，以获取一些疑难解答以及scanFragment中的实际情况: Kotlin-片段生命周期导航问题；为什么子片段会成为当前目的地?

I am clueless on how to approach this. See my earlier question for some troubleshooting and what really goes on in scanFragment: Kotlin - fragment lifecycle navigation issues; why does child fragment become current destination?

我怀疑我的导航设置有误，但是我在任何地方都找不到解决方案.

I suspect my navigation setup is wrong, but I can't find the solution anywhere.

我在下面发布了我的整个导航实现/代码.

I'm posting my entire navigation implementation/code below.

我的nav_graph设计:

我的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/nav_graph"
    app:startDestination="@id/mainFragment">

    <fragment
        android:id="@+id/scanFragment"
        android:name="xxxx.ui.scan.ScanFragment"
        android:label="@string/tab_bar_first_item_title"
        tools:layout="@layout/fragment_scan" >
        <action
            android:id="@+id/action_scanFragment_to_addVehicleFragment"
            app:destination="@id/addVehicleFragment"
            app:enterAnim="@anim/from_left"
            app:exitAnim="@anim/to_left" />
    </fragment>

    <fragment
        android:id="@+id/addVehicleFragment"
        android:name="xxxx.ui.scan.AddVehicleFragment"
        android:label="@string/add_vehicle_fragment_title_string"
        tools:layout="@layout/fragment_add_vehicle">
        <action
            android:id="@+id/action_addVehicleFragment_to_scanFragment"
            app:destination="@id/scanFragment" />
    </fragment>

    <fragment
        android:id="@+id/mainFragment"
        android:name="xxxx.ui.main.MainFragment"
        android:label="@string/tab_bar_second_item_title"
        tools:layout="@layout/fragment_main" />

    <fragment
        android:id="@+id/profileFragment"
        android:name="xxxx.ui.profile.ProfileFragment"
        android:label="@string/tab_bar_third_item_title"
        tools:layout="@layout/fragment_profile">

        <action
            android:id="@+id/actionMyVehicles"
            app:destination="@id/myVehiclesFragment"
            app:enterAnim="@anim/from_right"
            app:exitAnim="@anim/to_left" />

        <action
            android:id="@+id/actionMyRooms"
            app:destination="@+id/myRoomsFragment"
            app:enterAnim="@anim/from_right"
            app:exitAnim="@anim/to_left" />
    </fragment>

    <fragment
        android:id="@+id/myVehiclesFragment"
        android:name="xxxx.ui.profile.MyVehiclesFragment"
        android:label="fragment_my_vehicles"
        tools:layout="@layout/fragment_my_vehicles" >
        <action
            android:id="@+id/action_myVehiclesFragment_to_profileFragment"
            app:destination="@id/profileFragment"
            app:enterAnim="@anim/from_left"
            app:exitAnim="@anim/to_right" />
    </fragment>

    <fragment
        android:id="@+id/myRoomsFragment"
        android:name="xxxx.ui.profile.MyRoomsFragment"
        android:label="fragment_my_rooms"
        tools:layout="@layout/fragment_my_rooms" >
        <action
            android:id="@+id/action_myRoomsFragment_to_profileFragment"
            app:destination="@id/profileFragment"
            app:enterAnim="@anim/from_left"
            app:exitAnim="@anim/to_right" />
    </fragment>

</navigation>

我的主要活动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:id="@+id/main_activity_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/light_gray"
    tools:context=".MainActivity">

    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/navHostFragment"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:defaultNavHost="true"
        app:layout_constraintBottom_toTopOf="@+id/tabBar"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:navGraph="@navigation/nav_graph">

    </androidx.fragment.app.FragmentContainerView>

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/tabBar"
        android:layout_width="match_parent"
        android:layout_height="58dp"
        android:layout_alignParentBottom="true"
        app:elevation="2dp"
        app:itemBackground="@color/light_gray"
        app:itemIconSize="30dp"
        app:itemIconTint="@color/tab_bar_icon_tint_color"
        app:labelVisibilityMode="unlabeled"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:menu="@menu/tab_bar" />

</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity:

class MainActivity : AppCompatActivity() {

    private lateinit var viewBinding: ActivityMainBinding
    private lateinit var tabBar: BottomNavigationView
    private lateinit var navHostFragment: NavHostFragment

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        println("MainActivity || onCreate ||")

        // Initialize viewBinding object
        viewBinding = ActivityMainBinding.inflate(layoutInflater)

        // Hide the default navigation bar; we implement our own
        supportActionBar!!.hide()
        
        viewBinding.loadingPageLayout.visibility = View.GONE

        setContentView(viewBinding.root)

        setupBottomBarNavigation()
    }

    private fun setupBottomBarNavigation() {
        tabBar = viewBinding.tabBar
        navHostFragment = supportFragmentManager.findFragmentById(R.id.navHostFragment) as NavHostFragment
        val navigationController = navHostFragment.navController
        val appBarConfiguration = AppBarConfiguration(setOf(R.id.scanFragment, R.id.mainFragment, R.id.profileFragment))
        setupActionBarWithNavController(navigationController, appBarConfiguration)
        tabBar.setupWithNavController(navigationController)

        val navHost = supportFragmentManager.currentNavigationFragment
        println("Current navigation fragment: $navHost")

        
    }

    override fun onSupportNavigateUp() =
        Navigation.findNavController(this, R.id.navHostFragment).navigateUp()

请帮助一个绝望的家伙！

Please help a desperate fellow out!

推荐答案

问题不在导航组件中，而是-我认为-在我的ImageAnalyzer中.原来我不小心允许多次调用findNavController.navigate().现在，我已解决该问题，导航问题已解决.

The problem was not in Navigation Components but instead - I think - in my ImageAnalyzer. Turns out I accidentally allowed multiple calls to findNavController.navigate(). Now that I fixed that, my navigation issue is gone.

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