Navigate between different graphs with Navigation components

I have two activities, one holds all the fragments for the Login process, and the other one holds all the fragments for the main app.

Let's say I want to navigate from Activity1 (that holds all navigation graph of Login) to Activity2 (That holds all the navigation graph for the main app)



class LoginActivity : AppCompatActivity() {

override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_login)
}

fun goToMainActivity(){
startActivity(Intent(this,MainActivity::class.java))
finish()
}
}

Here I call the method goToMainActivity()




class LoginFragment : Fragment() {

override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
return inflater.inflate(R.layout.fragment_login,container,false)
}

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)

btn_go.setOnClickListener {
// call the method goToMainActivity() to kill all fragments contained by that Activity and move foward to MainActivity with another nav_graph
}
}
}

Since LoginActivity holds a nav_graph and is the navigation host for all the Login Fragments, now I want to kill all the fragments contained to LoginActivity and move towards a new Activity (MainActivity) that holds a different nav graph

Is this the good way to do it? Or I should navigate differently ?

You can migrate to a single Activity Navigation. In your Nav Graph add an Action to navigate between the last LoginFragemnt and MainFragment and select:

Pop Behaviour:
Pop To - Self
Inclusive - YES

This should automatically clear the stack for you and pressing back will close the App.

EDIT:
Or just manually add these two lines to your nav xml under the action that moves from the LoginFragment to the MainFragment:

app:popUpTo="@id/loginFragment"
app:popUpToInclusive="true"

You don't need to define a second activity, simply add a second navigation graph to your `nav_graph.xml` file. Something like:

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-xml -->

<?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/nav_graph"
app:startDestination="@id/loginFragment">

<fragment
android:id="@+id/loginFragment"
android:name="com.mycompany.loginFragment"
tools:layout="@layout/fragment_login"
android:label="Login" >
<action
android:id="@+id/action_loginFragment_to_new_graph"
app:destination="@id/new_graph" />
</fragment>

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

<!-- end snippet -->

Then, with your `navController`, navigate the action:

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-kotlin -->

navController.navigate(R.id.action_loginFragment_to_new_graph)

<!-- end snippet -->