Setting NavGraph programmatically

Question

In my activity layout, I have the following 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" />

My question is how can I set the navGraph programmatically? How can I convert the my_nav_host_fragment view instance in a NavHostFragment instance?

score 43 · Accepted Answer · edited Aug 24 '19 at 14:23

43

I found a solution:

//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

Based on: Navigation Architecture Component- Passing argument data to the startDestination

edited Aug 24 '19 at 14:23

Evgenii

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answered Jun 17 '18 at 18:22

amp

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Can you do this multiple times, setting a different graph at each time? – Klaasel Jul 19 '18 at 07:17
@Klaasel I think so. – amp Jul 23 '18 at 11:32
https://developer.android.com/topic/libraries/architecture/navigation/navigation-implementing#create_the_navhostfragment_programmatically @amp – Klaasel Jul 25 '18 at 10:55
Yes you can @klaasel :) Thanks amp this was super helpful – cesarferreira Aug 16 '18 at 15:44
1

I think the correct way to reference nav graph should be `R.navigation.my_nav_graph` – Ondřej Z Jul 24 '19 at 18:05

Tatsuya Fujisaki · Answer 2 · 2020-05-14T03:02:34.200

7

You can write in your Activity as follows.

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

edited May 14 '20 at 03:02

answered May 13 '20 at 16:25

Tatsuya Fujisaki

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Thracian · Answer 3 · 2020-09-02T09:16:11.150

5

Both of the answers caused exception when i used with DynamicNavHostFragment, so i used

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

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

edited Sep 02 '20 at 09:16

answered Aug 18 '20 at 07:25

Thracian

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`findNavController()` will search for controller in all child views and will return first controller, that is not null. If you have nested `nav_graph`s, your code can set graph to the wrong controller. – Peter Jan 19 '22 at 13:17

score 0 · Answer 4 · answered Aug 26 '22 at 16:32

My solution is this,

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

Setting NavGraph programmatically

4 Answers4

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