compose-navigation

name	compose-navigation
description	Implement navigation in Jetpack Compose using Navigation Compose. Use when asked to set up navigation, pass arguments between screens, handle deep links, or structure multi-screen apps.

Compose Navigation

Overview

Implement type-safe navigation in Jetpack Compose applications using the Navigation Compose library. This skill covers NavHost setup, argument passing, deep links, nested graphs, adaptive navigation, and testing.

Setup

Add the Navigation Compose dependency:

// build.gradle.kts
dependencies {
    implementation("androidx.navigation:navigation-compose:2.8.5")
    
    // For type-safe navigation (recommended)
    implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.7.3")
}

// Enable serialization plugin
plugins {
    kotlin("plugin.serialization") version "2.0.21"
}

---

Core Concepts

1. Define Routes (Type-Safe)

Use @Serializable data classes/objects for type-safe routes:

import kotlinx.serialization.Serializable

// Simple screen (no arguments)
@Serializable
object Home

// Screen with required argument
@Serializable
data class Detail(val itemId: String)

// Screen with multiple arguments
@Serializable
data class ProductDetail(
    val productId: String,
    val category: String,
    val fromSearch: Boolean = false
)

@Serializable
data class UserProfile(val userId: Long)

// Screen with optional argument
@Serializable
data class Settings(val section: String? = null)

2. Create NavHost & Basic Navigation

@Composable
fun AppNavigation() {
    val navController = rememberNavController()

    NavHost(
        navController = navController,
        startDestination = Home
    ) {
        composable<Home> {
            HomeScreen(
                onItemClick = { itemId ->
                    navController.navigate(Detail(itemId))
                },
                onSettingsClick = {
                    navController.navigate(Settings())
                }
            )
        }

        composable<Detail> { backStackEntry ->
            val detail: Detail = backStackEntry.toRoute()
            DetailScreen(
                itemId = detail.itemId,
                onBack = { navController.popBackStack() }
            )
        }

        composable<Settings> {
            SettingsScreen(
                onBack = { navController.popBackStack() }
            )
        }
    }
}

---

Navigation Patterns

Navigation with Arguments

@Composable
fun NavigationWithArgs() {
    val navController = rememberNavController()

    NavHost(navController = navController, startDestination = Home) {
        composable<Home> {
            HomeScreen(
                onProductClick = { productId, category ->
                    navController.navigate(
                        ProductDetail(
                            productId = productId,
                            category = category,
                            fromSearch = false
                        )
                    )
                }
            )
        }

        composable<ProductDetail> { backStackEntry ->
            val args: ProductDetail = backStackEntry.toRoute()
            ProductDetailScreen(
                productId = args.productId,
                category = args.category,
                showBackToSearch = args.fromSearch
            )
        }

        composable<UserProfile> { backStackEntry ->
            val args: UserProfile = backStackEntry.toRoute()
            UserProfileScreen(userId = args.userId)
        }
    }
}

Bottom Navigation

enum class BottomNavDestination(
    val route: Any,
    val icon: ImageVector,
    val label: String
) {
    HOME(Home, Icons.Default.Home, "Home"),
    SEARCH(Search, Icons.Default.Search, "Search"),
    FAVORITES(Favorites, Icons.Default.Favorite, "Favorites"),
    PROFILE(Profile, Icons.Default.Person, "Profile")
}

@Composable
fun MainScreenWithBottomNav() {
    val navController = rememberNavController()
    val navBackStackEntry by navController.currentBackStackEntryAsState()
    val currentDestination = navBackStackEntry?.destination

    Scaffold(
        bottomBar = {
            NavigationBar {
                BottomNavDestination.entries.forEach { destination ->
                    NavigationBarItem(
                        icon = {
                            Icon(destination.icon, contentDescription = destination.label)
                        },
                        label = { Text(destination.label) },
                        selected = currentDestination?.hasRoute(destination.route::class) == true,
                        onClick = {
                            navController.navigate(destination.route) {
                                // Pop up to start destination to avoid building up stack
                                popUpTo(navController.graph.findStartDestination().id) {
                                    saveState = true
                                }
                                // Avoid multiple copies of same destination
                                launchSingleTop = true
                                // Restore state when reselecting
                                restoreState = true
                            }
                        }
                    )
                }
            }
        }
    ) { innerPadding ->
        NavHost(
            navController = navController,
            startDestination = Home,
            modifier = Modifier.padding(innerPadding)
        ) {
            composable<Home> { HomeScreen() }
            composable<Search> { SearchScreen() }
            composable<Favorites> { FavoritesScreen() }
            composable<Profile> { ProfileScreen() }
        }
    }
}

Bottom Nav with Badges

@Composable
fun BottomNavWithBadges(
    cartCount: Int,
    notificationCount: Int
) {
    NavigationBar {
        NavigationBarItem(
            icon = { Icon(Icons.Default.Home, null) },
            label = { Text("Home") },
            selected = true,
            onClick = { }
        )

        NavigationBarItem(
            icon = {
                BadgedBox(
                    badge = {
                        if (cartCount > 0) {
                            Badge { Text("$cartCount") }
                        }
                    }
                ) {
                    Icon(Icons.Default.ShoppingCart, null)
                }
            },
            label = { Text("Cart") },
            selected = false,
            onClick = { }
        )
        // ... more items
    }
}

Navigation Drawer (Modal)

@Composable
fun ModalDrawerNavigation() {
    val drawerState = rememberDrawerState(initialValue = DrawerValue.Closed)
    val scope = rememberCoroutineScope()
    var selectedItem by remember { mutableStateOf(0) }
    
    // ... items setup

    ModalNavigationDrawer(
        drawerState = drawerState,
        drawerContent = {
            ModalDrawerSheet {
                // Header...
                // Navigation items
                items.forEachIndexed { index, item ->
                    NavigationDrawerItem(
                        icon = { Icon(item.icon, contentDescription = null) },
                        label = { Text(item.label) },
                        selected = index == selectedItem,
                        onClick = {
                            selectedItem = index
                            scope.launch { drawerState.close() }
                        },
                        modifier = Modifier.padding(NavigationDrawerItemDefaults.ItemPadding)
                    )
                }
                // Footer...
            }
        }
    ) {
        Scaffold(
            topBar = {
                TopAppBar(
                    title = { Text(items[selectedItem].label) },
                    navigationIcon = {
                        IconButton(onClick = { scope.launch { drawerState.open() } }) {
                            Icon(Icons.Default.Menu, "Open drawer")
                        }
                    }
                )
            }
        ) { padding ->
            Content(modifier = Modifier.padding(padding))
        }
    }
}

Adaptive Navigation (Rail/Drawer)

// Navigation Rail
@Composable
fun NavigationRailLayout() {
    var selectedItem by remember { mutableStateOf(0) }

    Row(modifier = Modifier.fillMaxSize()) {
        NavigationRail(
            header = {
                 FloatingActionButton(onClick = { }) { Icon(Icons.Default.Add, "Create") }
            }
        ) {
            Spacer(Modifier.weight(1f))
            railItems.forEachIndexed { index, item ->
                NavigationRailItem(
                    icon = { Icon(item.icon, null) },
                    label = { Text(item.label) },
                    selected = selectedItem == index,
                    onClick = { selectedItem = index }
                )
            }
            Spacer(Modifier.weight(1f))
        }

        // Main content
        Box(modifier = Modifier.weight(1f).fillMaxHeight()) {
             // Content switching logic
        }
    }
}

---

Deep Linking

Basic Deep Link Setup

AndroidManifest.xml:

<intent-filter>
    <action android:name="android.intent.action.VIEW" />
    <category android:name="android.intent.category.DEFAULT" />
    <category android:name="android.intent.category.BROWSABLE" />
    <data android:scheme="myapp" />
    <data android:scheme="https" android:host="myapp.com" />
</intent-filter>

Composable Setup:

@Composable
fun DeepLinkNavigation() {
    val navController = rememberNavController()

    NavHost(navController = navController, startDestination = Home) {
        composable<Home> { HomeScreen() }

        composable<ProductDetail>(
            deepLinks = listOf(
                navDeepLink<ProductDetail>(basePath = "https://myapp.com/product"),
                navDeepLink<ProductDetail>(basePath = "myapp://product")
            )
        ) { backStackEntry ->
            val args: ProductDetail = backStackEntry.toRoute()
            ProductDetailScreen(productId = args.productId)
        }
    }
}

Handling Intent in Activity

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            AppTheme {
                val navController = rememberNavController()
                // Handle deep link from intent
                LaunchedEffect(Unit) {
                    intent?.data?.let { uri -> navController.handleDeepLink(intent) }
                }
                AppNavigation(navController = navController)
            }
        }
    }

    override fun onNewIntent(intent: Intent) {
        super.onNewIntent(intent)
        setIntent(intent)
    }
}

---

Nested Navigation

@Composable
fun NestedNavigation() {
    val navController = rememberNavController()

    NavHost(navController = navController, startDestination = MainGraph) {
        // Main graph with bottom navigation
        navigation<MainGraph>(startDestination = Home) {
            composable<Home> {
                HomeScreen(onItemClick = { navController.navigate(Detail(it)) })
            }
            composable<Search> { SearchScreen() }
            composable<Profile> {
                ProfileScreen(onSettingsClick = { navController.navigate(SettingsGraph) })
            }
        }

        // Nested detail graph
        composable<Detail> { backStackEntry ->
            val args: Detail = backStackEntry.toRoute()
            DetailScreen(itemId = args.itemId)
        }

        // Separate settings graph
        navigation<SettingsGraph>(startDestination = SettingsMain) {
            composable<SettingsMain> {
                SettingsScreen(
                    onAccountClick = { navController.navigate(AccountSettings) },
                    onNotificationsClick = { navController.navigate(NotificationSettings) }
                )
            }
            composable<AccountSettings> { AccountSettingsScreen() }
            composable<NotificationSettings> { NotificationSettingsScreen() }
        }
    }
}

// Graph Routes
@Serializable object MainGraph
@Serializable object SettingsGraph
@Serializable object SettingsMain
@Serializable object AccountSettings
@Serializable object NotificationSettings

---

State Management & Animation

ViewModel Integration

@HiltViewModel
class NavigationViewModel @Inject constructor(
    private val savedStateHandle: SavedStateHandle
) : ViewModel() {

    private val _navigationEvents = MutableSharedFlow<NavigationEvent>()
    val navigationEvents = _navigationEvents.asSharedFlow()

    fun navigateToDetail(itemId: String) {
        viewModelScope.launch {
            _navigationEvents.emit(NavigationEvent.NavigateToDetail(itemId))
        }
    }
}

@Composable
fun NavigationHandler(navController: NavHostController, viewModel: NavigationViewModel = hiltViewModel()) {
    LaunchedEffect(Unit) {
        viewModel.navigationEvents.collect { event ->
            when (event) {
                is NavigationEvent.NavigateToDetail -> navController.navigate(Detail(event.itemId))
                NavigationEvent.NavigateBack -> navController.popBackStack()
            }
        }
    }
}

Back Handler

@Composable
fun ScreenWithBackHandler(onBack: () -> Unit) {
    var showExitDialog by remember { mutableStateOf(false) }

    // Intercept back press
    BackHandler { showExitDialog = true }

    if (showExitDialog) {
        AlertDialog(
            onDismissRequest = { showExitDialog = false },
            title = { Text("Exit App?") },
            text = { Text("Are you sure you want to exit?") },
            confirmButton = { TextButton(onClick = onBack) { Text("Exit") } },
            dismissButton = { TextButton(onClick = { showExitDialog = false }) { Text("Cancel") } }
        )
    }
    // Screen content...
}

Navigation Animations

NavHost(
    navController = navController,
    startDestination = Home,
    enterTransition = {
        slideIntoContainer(
            towards = AnimatedContentTransitionScope.SlideDirection.Left,
            animationSpec = tween(300)
        )
    },
    exitTransition = {
        slideOutOfContainer(
            towards = AnimatedContentTransitionScope.SlideDirection.Left,
            animationSpec = tween(300)
        )
    },
    popEnterTransition = {
        slideIntoContainer(
            towards = AnimatedContentTransitionScope.SlideDirection.Right,
            animationSpec = tween(300)
        )
    },
    popExitTransition = {
        slideOutOfContainer(
            towards = AnimatedContentTransitionScope.SlideDirection.Right,
            animationSpec = tween(300)
        )
    }
) {
    // ... destinations
}

---

Testing

Setup

// build.gradle.kts
androidTestImplementation("androidx.navigation:navigation-testing:2.8.5")

Test Navigation

class NavigationTest {
    @get:Rule
    val composeTestRule = createComposeRule()
    
    private lateinit var navController: TestNavHostController
    
    @Before
    fun setup() {
        composeTestRule.setContent {
            navController = TestNavHostController(LocalContext.current)
            navController.navigatorProvider.addNavigator(ComposeNavigator())
            AppNavHost(navController = navController)
        }
    }
    
    @Test
    fun verifyStartDestination() {
        composeTestRule
            .onNodeWithText("Welcome")
            .assertIsDisplayed()
    }
}

---

Critical Rules

DO

• Use @Serializable routes for type safety
• Pass only IDs/primitives as arguments
• Use popUpTo with launchSingleTop for bottom navigation
• Extract NavHost to a separate composable for testability
• Use SavedStateHandle.toRoute<T>() in ViewModels

DON'T

• Pass complex objects as navigation arguments
• Create NavController inside NavHost
• Navigate in LaunchedEffect without proper keys
• Forget FLAG_IMMUTABLE for PendingIntents (Android 12+)
• Use string-based routes (legacy pattern)