Navigate to a fragment from another graph without it being the start destination

Question

In my first graph, I have the following:

<?xml version="1.0" encoding="utf-8"?>
<navigation xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/firstGraph"
    app:startDestination="@id/listFragment">

    <fragment
        android:id="@+id/listFragment"
        android:name="com.example.ListFragment">

        <action
            android:id="@+id/action_list_to_details"
            app:destination="@id/detailsFragment" />

    </fragment>

    <fragment
        android:id="@+id/detailsFragment"
        android:name="com.example.DetailsFragment">

    </fragment>
</navigation>

In my second graph I have the following:

<?xml version="1.0" encoding="utf-8"?>
<navigation xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/secondGraph"
    app:startDestination="@id/dashboardFragment">

    <include app:graph="@navigation/firstGraph" />

    <fragment
        android:id="@+id/dashboardFragment"
        android:name="com.example.DashboardFragment">
        <action
            android:id="@+id/action_dashboard_to_notification"
            app:destination="@id/notificationFragment"/>
    </fragment>

    <fragment
        android:id="@+id/notificationFragment"
        android:name="com.example.NotificationsFragment">

        <action
            android:id="@+id/action_notification_to_details"
            app:destination="@id/firstGraph"/>

    </fragment>
</navigation>

I want to navigate from "notificationFragment" to "detailsFragment" directly without it being the start destination, with including the second graph stack

Answer 1

As per the nested graph documentation:

[Nested graphs] also provide a level of encapsulation — destinations outside of the nested graph do not have direct access to any of the destinations within the nested graph.

There is one exception to that, when you are navigating using a URI, effectively deep linking into any destination:

Unlike navigation using action or destination IDs, you can navigate to any URI in your graph, regardless of whether the destination is visible. You can navigate to a destination on the current graph or a destination on a completely different graph.

Therefore you can add an implicit deep link to your graph:

<fragment
    android:id="@+id/detailsFragment"
    android:name="com.example.DetailsFragment">
    <deepLink app:uri="android-app://your.package.name/details" />
</fragment>

Then navigate to that destination via URI:

val uri = Uri.parse("android-app://your.package.name/details")
navController.navigate(uri)

It doesn't matter what your URI is, as long as the <deepLink> and what you pass to navigate match. Any arguments you have would need to be encoded in the URL.