Add type-safe navigation

app/build.gradle.kts

@@ -25,6 +25,7 @@ plugins {
     id("com.google.android.gms.oss-licenses-plugin")
     alias(libs.plugins.baselineprofile)
     alias(libs.plugins.roborazzi)
+    alias(libs.plugins.kotlin.serialization)
 }
 
 android {
@@ -103,6 +104,7 @@ dependencies {
     implementation(libs.androidx.window.core)
     implementation(libs.kotlinx.coroutines.guava)
     implementation(libs.coil.kt)
+    implementation(libs.kotlinx.serialization.json)
 
     ksp(libs.hilt.compiler)
 

app/dependencies/prodReleaseRuntimeClasspath.txt

@@ -106,11 +106,11 @@ androidx.lifecycle:lifecycle-viewmodel:2.8.0
 androidx.loader:loader:1.0.0
 androidx.localbroadcastmanager:localbroadcastmanager:1.0.0
 androidx.metrics:metrics-performance:1.0.0-alpha04
-androidx.navigation:navigation-common-ktx:2.8.0-alpha06
-androidx.navigation:navigation-common:2.8.0-alpha06
-androidx.navigation:navigation-compose:2.8.0-alpha06
-androidx.navigation:navigation-runtime-ktx:2.8.0-alpha06
-androidx.navigation:navigation-runtime:2.8.0-alpha06
+androidx.navigation:navigation-common-ktx:2.8.0-beta01
+androidx.navigation:navigation-common:2.8.0-beta01
+androidx.navigation:navigation-compose:2.8.0-beta01
+androidx.navigation:navigation-runtime-ktx:2.8.0-beta01
+androidx.navigation:navigation-runtime:2.8.0-beta01
 androidx.print:print:1.0.0
 androidx.privacysandbox.ads:ads-adservices-java:1.0.0-beta05
 androidx.privacysandbox.ads:ads-adservices:1.0.0-beta05

app/src/main/AndroidManifest.xml

@@ -45,9 +45,13 @@
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
             <intent-filter>
-                <data
-                    android:scheme="https"
-                    android:host="www.nowinandroid.apps.samples.google.com" />
+                <action android:name="android.intent.action.VIEW" />
+
+                <category android:name="android.intent.category.DEFAULT" />
+                <category android:name="android.intent.category.BROWSABLE" />
+
+                <data android:scheme="https" />
+                <data android:host="www.nowinandroid.apps.samples.google.com" />
             </intent-filter>
         </activity>
 

app/src/main/kotlin/com/google/samples/apps/nowinandroid/navigation/NiaNavHost.kt

@@ -20,7 +20,7 @@ import androidx.compose.runtime.Composable
 import androidx.compose.ui.Modifier
 import androidx.navigation.compose.NavHost
 import com.google.samples.apps.nowinandroid.feature.bookmarks.navigation.bookmarksScreen
-import com.google.samples.apps.nowinandroid.feature.foryou.navigation.FOR_YOU_ROUTE
+import com.google.samples.apps.nowinandroid.feature.foryou.navigation.ForYouRoute
 import com.google.samples.apps.nowinandroid.feature.foryou.navigation.forYouScreen
 import com.google.samples.apps.nowinandroid.feature.interests.navigation.navigateToInterests
 import com.google.samples.apps.nowinandroid.feature.search.navigation.searchScreen
@@ -40,12 +40,11 @@ fun NiaNavHost(
     appState: NiaAppState,
     onShowSnackbar: suspend (String, String?) -> Boolean,
     modifier: Modifier = Modifier,
-    startDestination: String = FOR_YOU_ROUTE,
 ) {
     val navController = appState.navController
     NavHost(
         navController = navController,
-        startDestination = startDestination,
+        startDestination = ForYouRoute(),
         modifier = modifier,
     ) {
         forYouScreen(onTopicClick = navController::navigateToInterests)

app/src/main/kotlin/com/google/samples/apps/nowinandroid/navigation/TopLevelDestination.kt

@@ -19,6 +19,10 @@ package com.google.samples.apps.nowinandroid.navigation
 import androidx.compose.ui.graphics.vector.ImageVector
 import com.google.samples.apps.nowinandroid.R
 import com.google.samples.apps.nowinandroid.core.designsystem.icon.NiaIcons
+import com.google.samples.apps.nowinandroid.feature.bookmarks.navigation.BookmarksRoute
+import com.google.samples.apps.nowinandroid.feature.foryou.navigation.ForYouRoute
+import com.google.samples.apps.nowinandroid.feature.interests.navigation.InterestsRoute
+import kotlin.reflect.KClass
 import com.google.samples.apps.nowinandroid.feature.bookmarks.R as bookmarksR
 import com.google.samples.apps.nowinandroid.feature.foryou.R as forYouR
 import com.google.samples.apps.nowinandroid.feature.search.R as searchR
@@ -33,23 +37,27 @@ enum class TopLevelDestination(
     val unselectedIcon: ImageVector,
     val iconTextId: Int,
     val titleTextId: Int,
+    val route: KClass<*>,
 ) {
     FOR_YOU(
         selectedIcon = NiaIcons.Upcoming,
         unselectedIcon = NiaIcons.UpcomingBorder,
         iconTextId = forYouR.string.feature_foryou_title,
         titleTextId = R.string.app_name,
+        route = ForYouRoute::class,
     ),
     BOOKMARKS(
         selectedIcon = NiaIcons.Bookmarks,
         unselectedIcon = NiaIcons.BookmarksBorder,
         iconTextId = bookmarksR.string.feature_bookmarks_title,
         titleTextId = bookmarksR.string.feature_bookmarks_title,
+        route = BookmarksRoute::class,
     ),
     INTERESTS(
         selectedIcon = NiaIcons.Grid3x3,
         unselectedIcon = NiaIcons.Grid3x3,
         iconTextId = searchR.string.feature_search_interests,
         titleTextId = searchR.string.feature_search_interests,
+        route = InterestsRoute::class,
     ),
 }

app/src/main/kotlin/com/google/samples/apps/nowinandroid/ui/NiaApp.kt

@@ -60,6 +60,7 @@ import androidx.compose.ui.semantics.testTagsAsResourceId
 import androidx.compose.ui.unit.dp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.navigation.NavDestination
+import androidx.navigation.NavDestination.Companion.hasRoute
 import androidx.navigation.NavDestination.Companion.hierarchy
 import com.google.samples.apps.nowinandroid.R
 import com.google.samples.apps.nowinandroid.core.designsystem.component.NiaBackground
@@ -268,5 +269,5 @@ private fun Modifier.notificationDot(): Modifier =
 
 private fun NavDestination?.isTopLevelDestinationInHierarchy(destination: TopLevelDestination) =
     this?.hierarchy?.any {
-        it.route?.contains(destination.name, true) ?: false
+        it.hasRoute(destination.route)
     } ?: false

app/src/main/kotlin/com/google/samples/apps/nowinandroid/ui/NiaAppState.kt

@@ -22,6 +22,7 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.navigation.NavController
 import androidx.navigation.NavDestination
+import androidx.navigation.NavDestination.Companion.hasRoute
 import androidx.navigation.NavGraph.Companion.findStartDestination
 import androidx.navigation.NavHostController
 import androidx.navigation.compose.currentBackStackEntryAsState
@@ -32,11 +33,11 @@ import com.google.samples.apps.nowinandroid.core.data.repository.UserNewsResourc
 import com.google.samples.apps.nowinandroid.core.data.util.NetworkMonitor
 import com.google.samples.apps.nowinandroid.core.data.util.TimeZoneMonitor
 import com.google.samples.apps.nowinandroid.core.ui.TrackDisposableJank
-import com.google.samples.apps.nowinandroid.feature.bookmarks.navigation.BOOKMARKS_ROUTE
+import com.google.samples.apps.nowinandroid.feature.bookmarks.navigation.BookmarksRoute
 import com.google.samples.apps.nowinandroid.feature.bookmarks.navigation.navigateToBookmarks
-import com.google.samples.apps.nowinandroid.feature.foryou.navigation.FOR_YOU_ROUTE
+import com.google.samples.apps.nowinandroid.feature.foryou.navigation.ForYouRoute
 import com.google.samples.apps.nowinandroid.feature.foryou.navigation.navigateToForYou
-import com.google.samples.apps.nowinandroid.feature.interests.navigation.INTERESTS_ROUTE
+import com.google.samples.apps.nowinandroid.feature.interests.navigation.InterestsRoute
 import com.google.samples.apps.nowinandroid.feature.interests.navigation.navigateToInterests
 import com.google.samples.apps.nowinandroid.feature.search.navigation.navigateToSearch
 import com.google.samples.apps.nowinandroid.navigation.TopLevelDestination
@@ -90,11 +91,13 @@ class NiaAppState(
             .currentBackStackEntryAsState().value?.destination
 
     val currentTopLevelDestination: TopLevelDestination?
-        @Composable get() = when (currentDestination?.route) {
-            FOR_YOU_ROUTE -> FOR_YOU
-            BOOKMARKS_ROUTE -> BOOKMARKS
-            INTERESTS_ROUTE -> INTERESTS
-            else -> null
+        @Composable get() {
+            with(currentDestination) {
+                if (this?.hasRoute<ForYouRoute>() == true) return FOR_YOU
+                if (this?.hasRoute<BookmarksRoute>() == true) return BOOKMARKS
+                if (this?.hasRoute<InterestsRoute>() == true) return INTERESTS
+            }
+            return null
         }
 
     val isOffline = networkMonitor.isOnline

app/src/main/kotlin/com/google/samples/apps/nowinandroid/ui/interests2pane/Interests2PaneViewModel.kt

@@ -18,19 +18,27 @@ package com.google.samples.apps.nowinandroid.ui.interests2pane
 
 import androidx.lifecycle.SavedStateHandle
 import androidx.lifecycle.ViewModel
-import com.google.samples.apps.nowinandroid.feature.interests.navigation.TOPIC_ID_ARG
+import androidx.navigation.toRoute
+import com.google.samples.apps.nowinandroid.feature.interests.navigation.InterestsRoute
+import com.google.samples.apps.nowinandroid.feature.interests.navigation.TOPIC_ID_KEY
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.flow.StateFlow
 import javax.inject.Inject
 
+const val TOPIC_ID_KEY = "selectedTopicId"
+
 @HiltViewModel
 class Interests2PaneViewModel @Inject constructor(
     private val savedStateHandle: SavedStateHandle,
 ) : ViewModel() {
-    val selectedTopicId: StateFlow<String?> =
-        savedStateHandle.getStateFlow(TOPIC_ID_ARG, savedStateHandle[TOPIC_ID_ARG])
+
+    val route = savedStateHandle.toRoute<InterestsRoute>()
+    val selectedTopicId: StateFlow<String?> = savedStateHandle.getStateFlow(
+        key = TOPIC_ID_KEY,
+        initialValue = route.initialTopicId,
+    )
 
     fun onTopicClick(topicId: String?) {
-        savedStateHandle[TOPIC_ID_ARG] = topicId
+        savedStateHandle[TOPIC_ID_KEY] = topicId
     }
 }

app/src/main/kotlin/com/google/samples/apps/nowinandroid/ui/interests2pane/InterestsListDetailScreen.kt

@@ -36,34 +36,24 @@ import androidx.compose.runtime.setValue
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.navigation.NavGraphBuilder
-import androidx.navigation.NavType
 import androidx.navigation.compose.NavHost
 import androidx.navigation.compose.composable
 import androidx.navigation.compose.rememberNavController
-import androidx.navigation.navArgument
 import com.google.samples.apps.nowinandroid.feature.interests.InterestsRoute
-import com.google.samples.apps.nowinandroid.feature.interests.navigation.INTERESTS_ROUTE
-import com.google.samples.apps.nowinandroid.feature.interests.navigation.TOPIC_ID_ARG
+import com.google.samples.apps.nowinandroid.feature.interests.navigation.InterestsRoute
 import com.google.samples.apps.nowinandroid.feature.topic.TopicDetailPlaceholder
-import com.google.samples.apps.nowinandroid.feature.topic.navigation.TOPIC_ROUTE
-import com.google.samples.apps.nowinandroid.feature.topic.navigation.createTopicRoute
+import com.google.samples.apps.nowinandroid.feature.topic.navigation.TopicRoute
 import com.google.samples.apps.nowinandroid.feature.topic.navigation.navigateToTopic
 import com.google.samples.apps.nowinandroid.feature.topic.navigation.topicScreen
+import kotlinx.serialization.Serializable
 import java.util.UUID
 
-private const val DETAIL_PANE_NAVHOST_ROUTE = "detail_pane_route"
+@Serializable internal object TopicPlaceholderRoute
+
+@Serializable internal object DetailPaneNavHostRoute
 
 fun NavGraphBuilder.interestsListDetailScreen() {
-    composable(
-        route = INTERESTS_ROUTE,
-        arguments = listOf(
-            navArgument(TOPIC_ID_ARG) {
-                type = NavType.StringType
-                defaultValue = null
-                nullable = true
-            },
-        ),
-    ) {
+    composable<InterestsRoute> {
         InterestsListDetailScreen()
     }
 }
@@ -97,8 +87,9 @@ internal fun InterestsListDetailScreen(
         listDetailNavigator.navigateBack()
     }
 
-    var nestedNavHostStartDestination by remember {
-        mutableStateOf(selectedTopicId?.let(::createTopicRoute) ?: TOPIC_ROUTE)
+    var nestedNavHostStartRoute by remember {
+        val route = selectedTopicId?.let { TopicRoute(id = it) } ?: TopicPlaceholderRoute
+        mutableStateOf(route)
     }
     var nestedNavKey by rememberSaveable(
         stateSaver = Saver({ it.toString() }, UUID::fromString),
@@ -115,11 +106,11 @@ internal fun InterestsListDetailScreen(
             // If the detail pane was visible, then use the nestedNavController navigate call
             // directly
             nestedNavController.navigateToTopic(topicId) {
-                popUpTo(DETAIL_PANE_NAVHOST_ROUTE)
+                popUpTo<DetailPaneNavHostRoute>()
             }
         } else {
             // Otherwise, recreate the NavHost entirely, and start at the new destination
-            nestedNavHostStartDestination = createTopicRoute(topicId)
+            nestedNavHostStartRoute = TopicRoute(id = topicId)
             nestedNavKey = UUID.randomUUID()
         }
         listDetailNavigator.navigateTo(ListDetailPaneScaffoldRole.Detail)
@@ -141,15 +132,15 @@ internal fun InterestsListDetailScreen(
                 key(nestedNavKey) {
                     NavHost(
                         navController = nestedNavController,
-                        startDestination = nestedNavHostStartDestination,
-                        route = DETAIL_PANE_NAVHOST_ROUTE,
+                        startDestination = nestedNavHostStartRoute,
+                        route = DetailPaneNavHostRoute::class,
                     ) {
                         topicScreen(
                             showBackButton = !listDetailNavigator.isListPaneVisible(),
                             onBackClick = listDetailNavigator::navigateBack,
                             onTopicClick = ::onTopicClickShowDetailPane,
                         )
-                        composable(route = TOPIC_ROUTE) {
+                        composable<TopicPlaceholderRoute> {
                             TopicDetailPlaceholder()
                         }
                     }

build-logic/convention/src/main/kotlin/AndroidFeatureConventionPlugin.kt

@@ -28,6 +28,7 @@ class AndroidFeatureConventionPlugin : Plugin<Project> {
             pluginManager.apply {
                 apply("nowinandroid.android.library")
                 apply("nowinandroid.android.hilt")
+                apply("org.jetbrains.kotlin.plugin.serialization")
             }
             extensions.configure<LibraryExtension> {
                 defaultConfig {
@@ -45,8 +46,11 @@ class AndroidFeatureConventionPlugin : Plugin<Project> {
                 add("implementation", libs.findLibrary("androidx.hilt.navigation.compose").get())
                 add("implementation", libs.findLibrary("androidx.lifecycle.runtimeCompose").get())
                 add("implementation", libs.findLibrary("androidx.lifecycle.viewModelCompose").get())
+                add("implementation", libs.findLibrary("androidx.navigation.compose").get())
                 add("implementation", libs.findLibrary("androidx.tracing.ktx").get())
+                add("implementation", libs.findLibrary("kotlinx.serialization.json").get())
 
+                add("testImplementation", libs.findLibrary("androidx.navigation.testing").get())
                 add("androidTestImplementation", libs.findLibrary("androidx.lifecycle.runtimeTesting").get())
             }
         }

core/notifications/src/main/kotlin/com/google/samples/apps/nowinandroid/core/notifications/SystemTrayNotifier.kt

@@ -43,8 +43,8 @@ private const val NEWS_NOTIFICATION_REQUEST_CODE = 0
 private const val NEWS_NOTIFICATION_SUMMARY_ID = 1
 private const val NEWS_NOTIFICATION_CHANNEL_ID = ""
 private const val NEWS_NOTIFICATION_GROUP = "NEWS_NOTIFICATIONS"
-private const val DEEP_LINK_SCHEME_AND_HOST = "https://www.nowinandroid.apps.samples.google.com"
-private const val FOR_YOU_PATH = "foryou"
+const val DEEP_LINK_SCHEME_AND_HOST = "https://www.nowinandroid.apps.samples.google.com"
+const val FOR_YOU_PATH = "foryou"
 
 /**
  * Implementation of [Notifier] that displays notifications in the system tray.

feature/bookmarks/src/main/kotlin/com/google/samples/apps/nowinandroid/feature/bookmarks/navigation/BookmarksNavigation.kt

@@ -21,16 +21,18 @@ import androidx.navigation.NavGraphBuilder
 import androidx.navigation.NavOptions
 import androidx.navigation.compose.composable
 import com.google.samples.apps.nowinandroid.feature.bookmarks.BookmarksRoute
+import kotlinx.serialization.Serializable
 
-const val BOOKMARKS_ROUTE = "bookmarks_route"
+@Serializable object BookmarksRoute
 
-fun NavController.navigateToBookmarks(navOptions: NavOptions) = navigate(BOOKMARKS_ROUTE, navOptions)
+fun NavController.navigateToBookmarks(navOptions: NavOptions) =
+    navigate(route = BookmarksRoute, navOptions)
 
 fun NavGraphBuilder.bookmarksScreen(
     onTopicClick: (String) -> Unit,
     onShowSnackbar: suspend (String, String?) -> Boolean,
 ) {
-    composable(route = BOOKMARKS_ROUTE) {
+    composable<BookmarksRoute> {
         BookmarksRoute(onTopicClick, onShowSnackbar)
     }
 }

feature/foryou/build.gradle.kts

@@ -29,6 +29,7 @@ dependencies {
     implementation(libs.accompanist.permissions)
     implementation(projects.core.data)
     implementation(projects.core.domain)
+    implementation(project(":core:notifications"))
 
     testImplementation(libs.hilt.android.testing)
     testImplementation(libs.robolectric)

feature/foryou/src/main/kotlin/com/google/samples/apps/nowinandroid/feature/foryou/ForYouScreen.kt

@@ -106,7 +106,7 @@ import com.google.samples.apps.nowinandroid.core.ui.launchCustomChromeTab
 import com.google.samples.apps.nowinandroid.core.ui.newsFeed
 
 @Composable
-internal fun ForYouRoute(
+internal fun ForYouScreen(
     onTopicClick: (String) -> Unit,
     modifier: Modifier = Modifier,
     viewModel: ForYouViewModel = hiltViewModel(),

feature/foryou/src/main/kotlin/com/google/samples/apps/nowinandroid/feature/foryou/navigation/ForYouNavigation.kt

@@ -19,29 +19,27 @@ package com.google.samples.apps.nowinandroid.feature.foryou.navigation
 import androidx.navigation.NavController
 import androidx.navigation.NavGraphBuilder
 import androidx.navigation.NavOptions
-import androidx.navigation.NavType
 import androidx.navigation.compose.composable
-import androidx.navigation.navArgument
 import androidx.navigation.navDeepLink
-import com.google.samples.apps.nowinandroid.feature.foryou.ForYouRoute
+import com.google.samples.apps.nowinandroid.core.notifications.DEEP_LINK_SCHEME_AND_HOST
+import com.google.samples.apps.nowinandroid.core.notifications.FOR_YOU_PATH
+import com.google.samples.apps.nowinandroid.feature.foryou.ForYouScreen
+import kotlinx.serialization.Serializable
 
 const val LINKED_NEWS_RESOURCE_ID = "linkedNewsResourceId"
-const val FOR_YOU_ROUTE = "for_you_route/{$LINKED_NEWS_RESOURCE_ID}"
-private const val DEEP_LINK_URI_PATTERN =
-    "https://www.nowinandroid.apps.samples.google.com/foryou/{$LINKED_NEWS_RESOURCE_ID}"
 
-fun NavController.navigateToForYou(navOptions: NavOptions) = navigate(FOR_YOU_ROUTE, navOptions)
+private const val DEEP_LINK_BASE_PATH = "$DEEP_LINK_SCHEME_AND_HOST/$FOR_YOU_PATH"
+
+@Serializable data class ForYouRoute(val linkedNewsResourceId: String? = null)
+
+fun NavController.navigateToForYou(navOptions: NavOptions) = navigate(route = ForYouRoute(), navOptions)
 
 fun NavGraphBuilder.forYouScreen(onTopicClick: (String) -> Unit) {
-    composable(
-        route = FOR_YOU_ROUTE,
+    composable<ForYouRoute>(
         deepLinks = listOf(
-            navDeepLink { uriPattern = DEEP_LINK_URI_PATTERN },
-        ),
-        arguments = listOf(
-            navArgument(LINKED_NEWS_RESOURCE_ID) { type = NavType.StringType },
+            navDeepLink<ForYouRoute>(basePath = DEEP_LINK_BASE_PATH),
         ),
     ) {
-        ForYouRoute(onTopicClick)
+        ForYouScreen(onTopicClick)
     }
 }