android - 调用 getGraph() 之前必须先调用 setGraph()

Question

我有底部导航，我也替换了 <fragment>标记为 FragmentContainerView它给了我关于它没有设置 NavController 的错误，然后我被发布 this问题并解决了问题，但是当方向更改并在底部导航中选择项目时，我收到以下错误

java.lang.IllegalStateException: You must call setGraph() before calling getGraph()

fragment 容器

<androidx.fragment.app.FragmentContainerView
        android:id="@+id/nav_host_fragment"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:defaultNavHost="true"
        app:navGraph="@navigation/mobile_navigation" /

寻找 fragment

val navHostFragment = supportFragmentManager.findFragmentById(R.id.nav_host_fragment) as NavHostFragment
    val navController = navHostFragment.navController
    // Passing each menu ID as a set of Ids because each
    // menu should be considered as top level destinations.
    val appBarConfiguration = AppBarConfiguration(
        setOf(
            R.id.navigation_classes, R.id.navigation_schedule, R.id.navigation_settings
        )
    )
    setupActionBarWithNavController(navController, appBarConfiguration)
    navView.setupWithNavController(navController)

Answer 1

这是根据 2.2.0-rc03 release notes 修复的:

NavHostFragment now correctly restores the graph after a configuration change when used with FragmentContainerView. (b/143752103)

因此请确保您使用的是 2.2.0-rc03。