Navigating 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 {
    implementation "androidx.navigation:navigation-compose:2.4.0-beta02"
}

Kotlin

dependencies {
    implementation("androidx.navigation:navigation-compose:2.4.0-beta02")
}

Getting started

The NavController is the central API for the Navigation component. It is stateful and keeps track of the back stack of composables that make up the screens in your app and the state of each screen.

You can create a NavController by using the rememberNavController() method in your composable:

val navController = rememberNavController()

You should create the NavController in the place in your composable hierarchy where all composables that need to reference it have access to it. This follows the principles of state hoisting and allows you to use the NavController and the state it provides via currentBackStackEntryAsState() to be used as the source of truth for updating composables outside of your screens. See Integration with the bottom nav bar for an example of this functionality.

Creating a NavHost

Each NavController must be associated with a single NavHost composable. The NavHost links the NavController with a navigation graph that specifies the composable destinations that you should be able to navigate between. As you navigate between composables, the content of the NavHost is automatically recomposed. Each composable destination in your navigation graph is associated with a route.

Creating the NavHost requires the NavController previously created via rememberNavController() and the route of the starting destination of your graph. NavHost creation uses the lambda syntax from the Navigation Kotlin DSL to construct your navigation graph. You can add to your navigation structure by using the composable() method. This method requires that you provide a route and the composable that should be linked to the destination:

NavHost(navController = navController, startDestination = "profile") {
    composable("profile") { Profile(/*...*/) }
    composable("friendslist") { FriendsList(/*...*/) }
    /*...*/
}

To navigate to a composable destination in the navigation graph, you must use the navigate() method. navigate() takes a single String parameter that represents the destination’s route. To navigate from a composable within the navigation graph, call navigate():

@Composable
fun Profile(navController: NavController) {
    /*...*/
    Button(onClick = { navController.navigate("friends") }) {
        Text(text = "Navigate next")
    }
    /*...*/
}

You should only call navigate() as part of a callback and not as part of your composable itself, to avoid calling navigate() on every recomposition.

By default, navigate() adds your new destination to the back stack. You can modify the behavior of navigate by attaching additional navigation options to our navigate() call:

// Pop everything up to the "home" destination off the back stack before
// navigating to the "friends" destination
navController.navigate(“friends”) {
    popUpTo("home")
}

// Pop everything up to and including the "home" destination off
// the back stack before navigating to the "friends" destination
navController.navigate("friends") {
    popUpTo("home") { inclusive = true }
}

// Navigate to the "search” destination only if we’re not already on
// the "search" destination, avoiding multiple copies on the top of the
// back stack
navController.navigate("search") {
    launchSingleTop = true
}

See the popUpTo guide for more use cases.

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. You can specify another type by using the arguments parameter to set a type:

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

You should extract the NavArguments 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 the value to the route in place of the placeholder in the call to navigate:

navController.navigate("profile/user1234")

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

Adding 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 nullability = 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 = "me" })
) { backStackEntry ->
    Profile(navController, backStackEntry.arguments?.getString("userId"))
}

Now, even if there is no argument passed to the destination, the defaultValue of "me" will be used instead.

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

Navigation Compose supports implicit deep links that can be defined as part of the composable() function as well. Add them as a list using navDeepLink():

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, and/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 above, 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 will automatically deep link 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

Destinations can be grouped into a nested graph to modularize a particular flow in your app’s UI. An example of this could be a self-contained login flow.

The nested graph encapsulates its destinations. As with the root graph, a nested graph must have a destination identified as the start destination by its route. This is the destination that is navigated to when you navigate to the route associated with the nested graph.

To add a nested graph to your NavHost, you can use the navigation extension function:

NavHost(navController, startDestination = "home") {
    ...
    // Navigating to the graph via its route ('login') automatically
    // navigates to the graph's start destination - 'username'
    // therefore encapsulating the graph's internal routing logic
    navigation(startDestination = "username", route = "login") {
        composable("username") { ... }
        composable("password") { ... }
        composable("registration") { ... }
    }
    ...
}

It is strongly recommended that you split your navigation graph into multiple methods as the graph grows in size. This also allows multiple modules to contribute their own navigation graphs.

fun NavGraphBuilder.loginGraph(navController: NavController) {
    navigation(startDestination = "username", route = "login") {
        composable("username") { ... }
        composable("password") { ... }
        composable("registration") { ... }
    }
}

By making the method an extension method on NavGraphBuilder, you can use it alongside the prebuilt navigation, composable, and dialog extension methods:

NavHost(navController, startDestination = "home") {
    ...
    loginGraph(navController)
    ...
}

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 BottomNavBar. Doing this allows you to navigate by selecting the icons in the bottom bar.

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) via the hierarchy helper method.

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.

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 hybrid apps is to use the fragment-based Navigation component and use fragments to hold view-based screens, Compose screens, and screens that use both views and Compose. Once each screen fragment in your app is a wrapper around a composable, 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) -> ()) {
    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

We strongly recommended that you decouple the Navigation code from your composable destinations to enable testing each composable in isolation, separate from the NavHost composable.

The level of indirection provided by the composable lambda is what allows you to 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
) {
 …
}

Here we see that 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 = "me" })
) { backStackEntry ->
    Profile(backStackEntry.arguments?.getString("userId")) { friendUserId ->
        navController.navigate("profile?userId=$friendUserId")
    }
}

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 Implement navigation for adaptive UIs.