Navigation Graph

developer.android.com/guide/navigation/navigation-getting-started

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1. Include the Jetpack Navigation library
2. Add a NavHost to the activity
3. Create a navigation graph
4. Add fragment destinations to the navigation graph

nav_graph.xml

<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/startFragment">
    <fragment
        android:id="@+id/startFragment"
        android:name="com.example.cupcake.StartFragment"
        android:label="fragment_start"
        tools:layout="@layout/fragment_start" >
        <action
            android:id="@+id/action_startFragment_to_flavorFragment"
            app:destination="@id/flavorFragment" />
    </fragment>
    ...
</navigation>

StartFragment.kt

findNavController().navigate(R.id.action_startFragment_to_flavorFragment)

++ StartFragement.kt 에서 FlavorFragment로 가는 action_startFragment_to_flavorFragment 를 호출

Get the NavController using findNavController() method and call navigate() on it, passing in the action ID, R.id.action_startFragment_to_flavorFragment. Make sure this action ID matches the action declared in your nav_graph.xml.

 

Update title in app bar

MainActivity.kt

class MainActivity : AppCompatActivity(R.layout.activity_main) {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        val navHostFragment = supportFragmentManager
                .findFragmentById(R.id.nav_host_fragment) as NavHostFragment
        val navController = navHostFragment.navController

        setupActionBarWithNavController(navController)
    }
}

nav_graph.xml (res/navigation/)

<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/startFragment">
    <fragment
        android:id="@+id/startFragment"
        android:name="com.example.cupcake.StartFragment"
        android:label="Change label attribute what you want"
        tools:layout="@layout/fragment_start" >
        <action
            android:id="@+id/action_startFragment_to_flavorFragment"
            app:destination="@id/flavorFragment" />
    </fragment>
    ...
</navigation>

++android:label="Change label attribute what you want"