Navigation with Compose

The Navigation component provides support for Jetpack Compose applications. You can navigate between composables while taking advantage of the Navigation component's infrastructure and features.

Setup

To support Compose, use the following dependency in your app module's build.gradle file:

Groovy

dependencies {
    def nav_version = "2.7.7"

    implementation "androidx.navigation:navigation-compose:$nav_version"
}

Kotlin

dependencies {
    val nav_version = "2.7.7"

    implementation("androidx.navigation:navigation-compose:$nav_version")
}

Get started

When implementing navigation in an app, implement a navigation host, graph, and controller. For more information, see the Navigation overview.

For information on how to create a NavController in Compose, see the Compose section of Create a navigation controller.

Create a NavHost

For information on how to create a NavHost in Compose, see the Compose section of Design your navigation graph.

For information on navigating to a Composable, see Navigate to a destination in the architecture documentation.

Navigation Compose also supports passing arguments between composable destinations. In order to do this, you need to add argument placeholders to your route, similar to how you add arguments to a deep link when using the base navigation library:

NavHost(startDestination = "profile/{userId}") {
    ...
    composable("profile/{userId}") {...}
}

By default, all arguments are parsed as strings. The arguments parameter of composable() accepts a list of NamedNavArgument objects. You can quickly create a NamedNavArgument using the navArgument() method and then specify its exact type:

NavHost(startDestination = "profile/{userId}") {
    ...
    composable(
        "profile/{userId}",
        arguments = listOf(navArgument("userId") { type = NavType.StringType })
    ) {...}
}

You should extract the arguments from the NavBackStackEntry that is available in the lambda of the composable() function.

composable("profile/{userId}") { backStackEntry ->
    Profile(navController, backStackEntry.arguments?.getString("userId"))
}

To pass the argument to the destination, you need to add append it to the route when you make the navigate call:

navController.navigate("profile/user1234")

For a list of supported types, see Pass data between destinations.

Retrieve complex data when navigating

It is strongly advised not to pass around complex data objects when navigating, but instead pass the minimum necessary information, such as a unique identifier or other form of ID, as arguments when performing navigation actions:

// Pass only the user ID when navigating to a new destination as argument
navController.navigate("profile/user1234")

Complex objects should be stored as data in a single source of truth, such as the data layer. Once you land on your destination after navigating, you can then load the required information from the single source of truth by using the passed ID. To retrieve the arguments in your ViewModel that's responsible for accessing the data layer, use the SavedStateHandle of the ViewModel:

class UserViewModel(
    savedStateHandle: SavedStateHandle,
    private val userInfoRepository: UserInfoRepository
) : ViewModel() {

    private val userId: String = checkNotNull(savedStateHandle["userId"])

    // Fetch the relevant user information from the data layer,
    // ie. userInfoRepository, based on the passed userId argument
    private val userInfo: Flow<UserInfo> = userInfoRepository.getUserInfo(userId)

// …

}

This approach helps prevent data loss during configuration changes and any inconsistencies when the object in question is being updated or mutated.

For a more in depth explanation on why you should avoid passing complex data as arguments, as well as a list of supported argument types, see Pass data between destinations.

Add optional arguments

Navigation Compose also supports optional navigation arguments. Optional arguments differ from required arguments in two ways:

  • They must be included using query parameter syntax ("?argName={argName}")
  • They must have a defaultValue set, or have nullable = true (which implicitly sets the default value to null)

This means that all optional arguments must be explicitly added to the composable() function as a list:

composable(
    "profile?userId={userId}",
    arguments = listOf(navArgument("userId") { defaultValue = "user1234" })
) { backStackEntry ->
    Profile(navController, backStackEntry.arguments?.getString("userId"))
}

Now, even if there is no argument passed to the destination, the defaultValue, "user1234", is used instead.

The structure of handling the arguments through the routes means that your composables remain completely independent of Navigation and makes them much more testable.

Navigation Compose supports implicit deep links that can be defined as part of the composable() function as well. Its deepLinks parameter accepts a list of NavDeepLink objects which can be quickly created using the navDeepLink() method:

val uri = "https://www.example.com"

composable(
    "profile?id={id}",
    deepLinks = listOf(navDeepLink { uriPattern = "$uri/{id}" })
) { backStackEntry ->
    Profile(navController, backStackEntry.arguments?.getString("id"))
}

These deep links let you associate a specific URL, action or mime type with a composable. By default, these deep links are not exposed to external apps. To make these deep links externally available you must add the appropriate <intent-filter> elements to your app's manifest.xml file. To enable the deep link in the preceding example, you should add the following inside of the <activity> element of the manifest:

<activity …>
  <intent-filter>
    ...
    <data android:scheme="https" android:host="www.example.com" />
  </intent-filter>
</activity>

Navigation automatically deep links into that composable when the deep link is triggered by another app.

These same deep links can also be used to build a PendingIntent with the appropriate deep link from a composable:

val id = "exampleId"
val context = LocalContext.current
val deepLinkIntent = Intent(
    Intent.ACTION_VIEW,
    "https://www.example.com/$id".toUri(),
    context,
    MyActivity::class.java
)

val deepLinkPendingIntent: PendingIntent? = TaskStackBuilder.create(context).run {
    addNextIntentWithParentStack(deepLinkIntent)
    getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT)
}

You can then use this deepLinkPendingIntent like any other PendingIntent to open your app at the deep link destination.

Nested Navigation

For information on how to create nested navigation graphs, see Nested graphs.

Integration with the bottom nav bar

By defining the NavController at a higher level in your composable hierarchy, you can connect Navigation with other components such as the bottom navigation component. Doing this lets you navigate by selecting the icons in the bottom bar.

To use the BottomNavigation and BottomNavigationItem components, add the androidx.compose.material dependency to your Android application.

Groovy

dependencies {
    implementation "androidx.compose.material:material:1.6.2"
}

android {
    buildFeatures {
        compose true
    }

    composeOptions {
        kotlinCompilerExtensionVersion = "1.5.10"
    }

    kotlinOptions {
        jvmTarget = "1.8"
    }
}

Kotlin

dependencies {
    implementation("androidx.compose.material:material:1.6.2")
}

android {
    buildFeatures {
        compose = true
    }

    composeOptions {
        kotlinCompilerExtensionVersion = "1.5.10"
    }

    kotlinOptions {
        jvmTarget = "1.8"
    }
}

To link the items in a bottom navigation bar to routes in your navigation graph, it is recommended to define a sealed class, such as Screen seen here, that contains the route and String resource ID for the destinations.

sealed class Screen(val route: String, @StringRes val resourceId: Int) {
    object Profile : Screen("profile", R.string.profile)
    object FriendsList : Screen("friendslist", R.string.friends_list)
}

Then place those items in a list that can be used by the BottomNavigationItem:

val items = listOf(
   Screen.Profile,
   Screen.FriendsList,
)

In your BottomNavigation composable, get the current NavBackStackEntry using the currentBackStackEntryAsState() function. This entry gives you access to the current NavDestination. The selected state of each BottomNavigationItem can then be determined by comparing the item's route with the route of the current destination and its parent destinations to handle cases when you are using nested navigation using the NavDestination hierarchy.

The item's route is also used to connect the onClick lambda to a call to navigate so that tapping on the item navigates to that item. By using the saveState and restoreState flags, the state and back stack of that item is correctly saved and restored as you swap between bottom navigation items.

val navController = rememberNavController()
Scaffold(
  bottomBar = {
    BottomNavigation {
      val navBackStackEntry by navController.currentBackStackEntryAsState()
      val currentDestination = navBackStackEntry?.destination
      items.forEach { screen ->
        BottomNavigationItem(
          icon = { Icon(Icons.Filled.Favorite, contentDescription = null) },
          label = { Text(stringResource(screen.resourceId)) },
          selected = currentDestination?.hierarchy?.any { it.route == screen.route } == true,
          onClick = {
            navController.navigate(screen.route) {
              // Pop up to the start destination of the graph to
              // avoid building up a large stack of destinations
              // on the back stack as users select items
              popUpTo(navController.graph.findStartDestination().id) {
                saveState = true
              }
              // Avoid multiple copies of the same destination when
              // reselecting the same item
              launchSingleTop = true
              // Restore state when reselecting a previously selected item
              restoreState = true
            }
          }
        )
      }
    }
  }
) { innerPadding ->
  NavHost(navController, startDestination = Screen.Profile.route, Modifier.padding(innerPadding)) {
    composable(Screen.Profile.route) { Profile(navController) }
    composable(Screen.FriendsList.route) { FriendsList(navController) }
  }
}

Here you take advantage of the NavController.currentBackStackEntryAsState() method to hoist the navController state out of the NavHost function, and share it with the BottomNavigation component. This means the BottomNavigation automatically has the most up-to-date state.

Type safety in Navigation Compose

The code on this page isn't type-safe. You can call the navigate() function with inexisting routes or incorrect arguments. However, you can structure your Navigation code to be type-safe at runtime. By doing so, you can avoid crashes and make sure that:

  • The arguments you provide when navigating to a destination or navigation graph are the right types and that all required arguments are present.
  • The arguments you retrieve from SavedStateHandle are the correct types.

For more information about this, see Type safety in Kotlin DSL and Navigation Compose.

Interoperability

If you want to use the Navigation component with Compose, you have two options:

  • Define a navigation graph with the Navigation component for fragments.
  • Define a navigation graph with a NavHost in Compose using Compose destinations. This is possible only if all of the screens in the navigation graph are composables.

Therefore, the recommendation for mixed Compose and Views apps is to use the Fragment-based Navigation component. Fragments will then hold View-based screens, Compose screens, and screens that use both Views and Compose. Once each Fragment's contents are in Compose, the next step is to tie all of those screens together with Navigation Compose and remove all of the Fragments.

In order to change destinations inside Compose code, you expose events that can be passed to and triggered by any composable in the hierarchy:

@Composable
fun MyScreen(onNavigate: (Int) -> Unit) {
    Button(onClick = { onNavigate(R.id.nav_profile) } { /* ... */ }
}

In your fragment, you make the bridge between Compose and the fragment-based Navigation component by finding the NavController and navigating to the destination:

override fun onCreateView( /* ... */ ) {
    setContent {
        MyScreen(onNavigate = { dest -> findNavController().navigate(dest) })
    }
}

Alternatively, you can pass the NavController down your Compose hierarchy. However, exposing simple functions is much more reusable and testable.

Testing

Decouple the navigation code from your composable destinations to enable testing each composable in isolation, separate from the NavHost composable.

This means that you shouldn't pass the navController directly into any composable and instead pass navigation callbacks as parameters. This allows all your composables to be individually testable, as they don't require an instance of navController in tests.

The level of indirection provided by the composable lambda is what lets you separate your Navigation code from the composable itself. This works in two directions:

  • Pass only parsed arguments into your composable
  • Pass lambdas that should be triggered by the composable to navigate, rather than the NavController itself.

For example, a Profile composable that takes in a userId as input and allows users to navigate to a friend's profile page might have the signature of:

@Composable
fun Profile(
    userId: String,
    navigateToFriendProfile: (friendUserId: String) -> Unit
) {
 …
}

This way, the Profile composable works independently from Navigation, allowing it to be tested independently. The composable lambda would encapsulate the minimal logic needed to bridge the gap between the Navigation APIs and your composable:

composable(
    "profile?userId={userId}",
    arguments = listOf(navArgument("userId") { defaultValue = "user1234" })
) { backStackEntry ->
    Profile(backStackEntry.arguments?.getString("userId")) { friendUserId ->
        navController.navigate("profile?userId=$friendUserId")
    }
}

It is recommended to write tests that cover your app navigation requirements by testing the NavHost, navigation actions passed to your composables as well as your individual screen composables.

Testing the NavHost

To begin testing your NavHost , add the following navigation-testing dependency:

dependencies {
// ...
  androidTestImplementation "androidx.navigation:navigation-testing:$navigationVersion"
  // ...
}

You can set up your NavHost test subject and pass an instance of the navController instance to it. For this, the navigation testing artifact provides a TestNavHostController. A UI test that verifies the start destination of your app and NavHost would look like this:

class NavigationTest {

    @get:Rule
    val composeTestRule = createComposeRule()
    lateinit var navController: TestNavHostController

    @Before
    fun setupAppNavHost() {
        composeTestRule.setContent {
            navController = TestNavHostController(LocalContext.current)
            navController.navigatorProvider.addNavigator(ComposeNavigator())
            AppNavHost(navController = navController)
        }
    }

    // Unit test
    @Test
    fun appNavHost_verifyStartDestination() {
        composeTestRule
            .onNodeWithContentDescription("Start Screen")
            .assertIsDisplayed()
    }
}

Testing navigation actions

You can test your navigation implementation in multiple ways, by performing clicks on the UI elements and then either verifying the displayed destination or by comparing the expected route against the current route.

As you want to test your concrete app's implementation, clicks on the UI are preferable. To learn how to test this alongside individual composable functions in isolation, make sure to check out the Testing in Jetpack Compose codelab.

You also can use the navController to check your assertions by comparing the current String route to the expected one, using navController's currentBackStackEntry:

@Test
fun appNavHost_clickAllProfiles_navigateToProfiles() {
    composeTestRule.onNodeWithContentDescription("All Profiles")
        .performScrollTo()
        .performClick()

    val route = navController.currentBackStackEntry?.destination?.route
    assertEquals(route, "profiles")
}

For more guidance on Compose testing basics, see Testing your Compose layout and the Testing in Jetpack Compose codelab. To learn more about advanced testing of navigation code, visit the Test Navigation guide.

Learn more

To learn more about Jetpack Navigation, see Get started with the Navigation component or take the Jetpack Compose Navigation codelab.

To learn how to design your app's navigation so it adapts to different screen sizes, orientations, and form factors, see Navigation for responsive UIs.

To learn about a more advanced Compose navigation implementation in a modularized app, including concepts like nested graphs and bottom navigation bar integration, take a look at the Now in Android app on GitHub.

Samples