NavigationUI.setupActionBarWithNavController 导致应用程序在 Android 在后台终止应用程序后启动时崩溃

Question

在我的 activity onCreate 方法中，我使用以下方式设置我的 actionBar 以显示和处理向上按钮上的点击：

val navController = this.findNavController(R.id.exerciseNavHostFragment)
NavigationUI.setupActionBarWithNavController(this, navController)

当我将我的应用程序发送到后台并被 OS 杀死时，就会出现此问题，而当我启动该应用程序时，它会崩溃。尝试再次启动该应用程序，它运行没有问题，崩溃仅发生在 kill 后的第一个应用程序启动时。

应用程序在 NavigationUI.setupActionBarWithNavController 行崩溃，崩溃日志如下（在崩溃前检查 navController 显示图表为空）：

06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime: FATAL EXCEPTION: main
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime: Process: com.rawcode.calisthenicsmastery, PID: 6624
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.rawcode.calisthenicsmastery/com.rawcode.calisthenicsmastery.exercises.ExercisesActivity}: java.lang.IllegalStateException: You must call setGraph() before calling getGraph()
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3160)
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3303)
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1991)
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  at android.os.Handler.dispatchMessage(Handler.java:106)
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  at android.os.Looper.loop(Looper.java:216)
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  at android.app.ActivityThread.main(ActivityThread.java:7258)
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  at java.lang.reflect.Method.invoke(Native Method)
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494)
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:975)
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime: Caused by: java.lang.IllegalStateException: You must call setGraph() before calling getGraph()
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  at androidx.navigation.NavController.getGraph(NavController.java:677)
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  at androidx.navigation.ui.NavigationUI.setupActionBarWithNavController(NavigationUI.java:168)
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  at com.rawcode.calisthenicsmastery.exercises.ExercisesActivity.onCreate(ExercisesActivity.kt:30)
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  at android.app.Activity.performCreate(Activity.java:7353)
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  at android.app.Activity.performCreate(Activity.java:7344)
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1275)
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3140)
06-08 15:02:55.262 10162  6624  6624 E AndroidRuntime:  ... 11 more

我没有在 SO 上找到任何类似的问题，而且我是 Android 开发的新手，感谢您对我可能做错的任何帮助。

我使用最新的导航依赖：

// Navigation
    implementation "android.arch.navigation:navigation-fragment-ktx:2.3.0"
    implementation "android.arch.navigation:navigation-ui-ktx:2.3.0"

该应用程序有一个底部导航栏，可在活动之间切换，每个 activity 都有自己的 navHostFragment。这是我的主要 activity 布局 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"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    
    <fragment
        android:id="@+id/exerciseNavHostFragment"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:navigationBarColor="@color/navigationBarColor"
        app:layout_constraintBottom_toTopOf="@+id/navigation"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="1.0"
        app:defaultNavHost="true"
        app:navGraph="@navigation/exercise_navigation" />

    <include
        android:id="@+id/navigation"
        layout="@layout/item_bottom_navigation"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        app:layout_constraintBottom_toBottomOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

Answer 1

您使用了错误的依赖项。当你使用

implementation "android.arch.navigation:navigation-fragment-ktx:2.3.0"
implementation "android.arch.navigation:navigation-ui-ktx:2.3.0"

您实际上使用的不是 Navigation 2.3.0，而是 android.arch.navigation 的最新版本 - Navigation 1.0.0。

您需要更新依赖项以匹配 Navigation Declaring dependencies documentation 上的依赖项并使用 androidx.navigation:

implementation "androidx.navigation:navigation-fragment-ktx:2.3.0"
implementation "androidx.navigation:navigation-ui-ktx:2.3.0"

NavigationUI.setupActionBarWithNavController 导致应用程序在 Android 在后台终止应用程序后启动时崩溃

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