您必须在调用 getGraph() 之前调用 setGraph()

Question

我有底部导航我也用 FragmentContainerView 替换了 <fragment> 标签，它给我错误关于它没有设置 NavController，然后我被发布问题并解决了问题，但是当方向改变并在底部导航中选择项目时我得到了以下错误

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

片段容器

<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" /

寻找片段

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:

固定的

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

所以请确保您使用的是 2.2.0-rc03。

Answer 2

使用导航 UI 的最新版本：

// navigation
implementation "androidx.navigation:navigation-fragment:2.3.0-alpha02"
implementation "androidx.navigation:navigation-ui:2.3.0-alpha02"

它修复了新版本

Answer 3

按照此 link 解决此问题 https://developer.android.com/jetpack/androidx/releases/navigation 简单来说，将您的依赖项升级到应用程序模块

中的以下依赖项

def nav_version = "2.3.0-alpha05"

// Java

implementation "androidx.navigation:navigation-fragment:$nav_version"
implementation "androidx.navigation:navigation-ui:$nav_version"

//科特林

implementation "androidx.navigation:navigation-fragment-ktx:$nav_version"
implementation "androidx.navigation:navigation-ui-ktx:$nav_version"

//动态特性模块支持

implementation "androidx.navigation:navigation-dynamic-features-fragment:$nav_version"

// 测试导航

androidTestImplementation "androidx.navigation:navigation-testing:$nav_version"

如果您使用安全参数，则在依赖项下的项目模块中

  def nav_version = "2.3.0-alpha05"
    classpath "androidx.navigation:navigation-safe-args-gradle-plugin:$nav_version"

解决了我的问题..

Answer 4

如果您像我一样忘记添加到您的FragmentContainerView

，您会遇到同样的错误

app:navGraph="@navigation/nav_graph"
app:defaultNavHost="true"

您必须在调用 getGraph() 之前调用 setGraph()

You must call setGraph() before calling getGraph()

android

android-fragments

bottomnavigationview

orientation-changes