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？如何将

my_nav_host_fragment

视图实例转换为

NavHostFragment

实例？

Answer 1

我找到了解决方案：

//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：导航架构组件 - 将参数数据传递到 startDestination

Answer 2

您可以在您的 Activity 中编写如下内容。

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

Answer 3

当我与 DynamicNavHostFragment 一起使用时，这两个答案都会导致异常，所以我使用了

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

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

Answer 4

我的解决方案是这样的，

val myNavHostFragment = supportFragmentManager
        .findFragmentById(R.id.navHostFragmentMain) as NavHostFragment
    val inflater = myNavHostFragment.navController.navInflater
    val graph = inflater.inflate(R.navigation.nav_graph)
    myNavHostFragment.navController.graph = graph

Answer 5

在爪哇中：

        FragmentManager fragmentManager = getChildFragmentManager();

        NavHostFragment navHostFragment = NavHostFragment.create(R.navigation.nav_graph);

        FragmentTransaction transaction = fragmentManager.beginTransaction();
        transaction.replace(R.id.nav_host_fragment, navHostFragment);
        transaction.setPrimaryNavigationFragment(navHostFragment);
        transaction.commit();