以编程方式设置NavGraph

Question

在我的活动布局中，我有以下NavHostFragment

<fragment
            android:id="@+id/my_nav_host_fragment"
            android:layout_height="match_parent"
            android:layout_width="match_parent"
            android:name="androidx.navigation.fragment.NavHostFragment"
            app:defaultNavHost="true"
            app:navGraph="@navigation/my_nav_graph" />

我的问题是如何以编程方式设置navGraph？如何在NavHostFragment实例中转换my_nav_host_fragment视图实例？

Answer 1

我找到了一个解决方案：

//Setup the navGraph for this activity
val myNavHostFragment: NavHostFragment = my_nav_host_fragment as NavHostFragment
val inflater = myNavHostFragment.navController.navInflater
val graph = inflater.inflate(R.navigation.my_nav_graph)
myNavHostFragment.navController.graph = graph

基于：Navigation Architecture Component- Passing argument data to the startDestination

Answer 2

你可以在你的活动中这样写。

findNavController(R.id.my_nav_host_fragment).setGraph(R.navigation.my_nav_graph)

Answer 3

当我使用DynamicNavHostFragment时，这两个答案都引起了异常，所以我使用

val navHostFragment: NavHostFragment = supportFragmentManager
    .findFragmentById(R.id. my_nav_host_fragment) as NavHostFragment

navHostFragment.findNavController().setGraph(R.navigation. my_nav_graph)