Use Navigation actions and Fragments

You can build connections between fragments using navigation actions. Evoking a navigation action takes the user from one destination to another. This guide explains what actions are and demonstrates how you can create and use them.

Overview

Each action has a unique ID and can contain additional attributes, such as a destination. The destination defines the screen to which the app takes the user when they trigger the action. The action can also use arguments to carry data from one destination to another.

• Safe Args: Using actions, you can replace resource IDs with Safe Args-generated operations, providing additional compile-time safety.
• Animations: You can also animate transitions between the destinations. For more information, see Animate transitions between destinations.

Examples

Define actions in your navigation graph XML file using the <action> tags. The following snippet implements an action that represents a transition from FragmentA to FragmentB.

<fragment
android:id="@+id/fragmentA"
android:name="com.example.FragmentA">
<action
android:id="@+id/action_fragmentA_to_fragmentB"
app:destination="@id/fragmentB"/>
</fragment>

Navigate using an action

To navigate using this action, you call NavController.navigate() and pass it the action's id:

navController.navigate(R.id.action_fragmentA_to_fragmentB)

Global actions

You can use global actions to navigate to a destination from anywhere.

For any destination in your app that is accessible through more than one path, define a corresponding global action that navigates to that destination.

Consider the following example. The results_winner and game_over destinations both need to pop up to the home destination. The action_pop_out_of_game action provides the ability to do so; action_pop_out_of_gameis a global action outside of any specific fragment. That means you can reference and call it anywhere within the in_game_nav_graph.

<?xmlversion="1.0"encoding="utf-8"?>
<navigationxmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/in_game_nav_graph"
app:startDestination="@id/in_game">
<!--Actionbacktodestinationwhichlaunchedintothisin_game_nav_graph-->
<actionandroid:id="@+id/action_pop_out_of_game"
app:popUpTo="@id/in_game_nav_graph"
app:popUpToInclusive="true"/>
<fragment
android:id="@+id/in_game"
android:name="com.example.android.gamemodule.InGame"
android:label="Game">
<action
android:id="@+id/action_in_game_to_resultsWinner"
app:destination="@id/results_winner"/>
<action
android:id="@+id/action_in_game_to_gameOver"
app:destination="@id/game_over"/>
</fragment>
<fragment
android:id="@+id/results_winner"
android:name="com.example.android.gamemodule.ResultsWinner"/>
<fragment
android:id="@+id/game_over"
android:name="com.example.android.gamemodule.GameOver"
android:label="fragment_game_over"
tools:layout="@layout/fragment_game_over"/>
</navigation>