Navigation Architecture Component - Activities

I managed to navigate from one activity to another without hosting a Fragment by using ActivityNavigator.

ActivityNavigator(this)
                    .createDestination()
                    .setIntent(Intent(this, SecondActivity::class.java))
                    .navigate(null, null)

I also managed to navigate from one activity to another without hosting a Fragment by using ActivityNavigator.

Kotlin:

val activityNavigator = ActivityNavigator( context!!)
                activityNavigator.navigate(
                    activityNavigator.createDestination().setIntent(
                        Intent(
                            context!!,
                            SecondActivity::class.java
                        )
                    ), null, null, null
                )

Java:

ActivityNavigator activityNavigator = new ActivityNavigator(this);
activityNavigator.navigate(activityNavigator.createDestination().setIntent(new Intent(this, SecondActivity.class)), null, null, null);

nav_graph.xml

<fragment android:id="@+id/fragment"
        android:name="com.codingwithmitch.navigationcomponentsexample.SampleFragment"
        android:label="fragment_sample"
        tools:layout="@layout/fragment_sample">

    <action
            android:id="@+id/action_confirmationFragment_to_secondActivity"
            app:destination="@id/secondActivity" />

</fragment>
<activity
        android:id="@+id/secondActivity"
        android:name="com.codingwithmitch.navigationcomponentsexample.SecondActivity"
        android:label="activity_second"
        tools:layout="@layout/activity_second" />

Kotlin:

lateinit var navController: NavController
navController = Navigation.findNavController(view)
navController!!.navigate(R.id.action_confirmationFragment_to_secondActivity)

The navigation graph only exists within a single activity. As per the Migrate to Navigation guide, <activity> destinations can be used to start an Activity from within the navigation graph, but once that second activity is started, it is totally separate from the original navigation graph (it could have its own graph or just be a simple activity).

You can add an Activity destination to your navigation graph via the visual editor (by hitting the + button and then selecting an activity in your project) or by manually adding the XML:

<activity
    android:id="@+id/secondActivity"
    android:name="com.example.SecondActivity" />

Then, you can navigate to that activity (i.e., start the activity) by using it just like any other destination:

Navigation.findNavController(view).navigate(R.id.secondActivity);