Kotlin

Question

问题

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

我做的时候出现错误

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

在扫描片段中。这意味着当前目的地是 addVehicleFragment，但它应该是 scanFragment。

我对如何解决这个问题一无所知。请参阅我之前的问题以了解一些故障排除以及 scanFragment 中真正发生的事情： Kotlin - fragment lifecycle navigation issues; why does child fragment become current destination?

我怀疑我的导航设置有误，但我找不到解决办法。

我在下面发布我的整个导航 implementation/code。

我的nav_graph设计：

我的nav_graphXML:

<?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Activity 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>

主要Activity:

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！

Answer 1

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()。既然我解决了这个问题，我的导航问题就消失了。

Answer 2

如果有人因为多次点击屏幕而遇到同样的问题。导航前先检查当前目的地即可解决

例如

片段 A、B 和 C

在点击片段 A 中导航到 C 的按钮时从 A 导航到 B 在某些情况下可能会导致崩溃

为此，您应该先检查当前目的地，如下所示：

if(findNavController().currentDestination?.id==R.id.AFragment)
   findNavController().navigate(
   AFragmentDirections.actionAFragmentToCFragment()
 )

Kotlin - 导航组件 - 无法从当前目的地找到导航 action/destination

Kotlin - Navigation Components - Navigation action/destination cannot be found from the current destination

android-architecture-navigation