Migrate topic feature to Nav3

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

@@ -30,7 +30,7 @@ import com.google.samples.apps.nowinandroid.feature.foryou.navigation.forYouSect
 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.searchScreen
-import com.google.samples.apps.nowinandroid.feature.topic.navigation.navigateToTopic
+import com.google.samples.apps.nowinandroid.feature.topic.navigation.TopicRoute
 import com.google.samples.apps.nowinandroid.feature.topic.navigation.topicScreen
 import com.google.samples.apps.nowinandroid.navigation.TopLevelDestination.INTERESTS
 import com.google.samples.apps.nowinandroid.ui.NiaAppState
@@ -64,13 +64,11 @@ fun NiaNavHost(
                         modifier = modifier,
                     ) {
                         forYouSection(
-                            onTopicClick = navController::navigateToTopic,
+                            onTopicClick = {
+                                nav3Navigator.goTo(route = TopicRoute(it))
+                            },
                         ) {
-                            topicScreen(
-                                showBackButton = true,
-                                onBackClick = navController::popBackStack,
-                                onTopicClick = navController::navigateToTopic,
-                            )
+                            composable<TopicRoute>{}
                         }
                         composable<BookmarksRoute> {}
                         searchScreen(
@@ -89,6 +87,13 @@ fun NiaNavHost(
                 },
                 onShowSnackbar = onShowSnackbar
             )
+            topicScreen(
+                showBackButton = true,
+                onBackClick = { nav3Navigator.goBack() },
+                onTopicClick = {
+                    nav3Navigator.goTo(route = TopicRoute(it))
+                },
+            )
         },
     )
 }

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

@@ -30,8 +30,8 @@ import androidx.navigation.NavGraph.Companion.findStartDestination
 import androidx.navigation.NavHostController
 import androidx.navigation.NavOptions
 import androidx.navigation.compose.rememberNavController
-import androidx.navigation.internalToRoute
 import androidx.navigation.navOptions
+import androidx.navigation.toRoute
 import androidx.tracing.trace
 import com.google.samples.apps.nowinandroid.core.data.repository.UserNewsResourceRepository
 import com.google.samples.apps.nowinandroid.core.data.util.NetworkMonitor
@@ -41,6 +41,7 @@ import com.google.samples.apps.nowinandroid.feature.bookmarks.api.navigation.Boo
 import com.google.samples.apps.nowinandroid.feature.foryou.navigation.navigateToForYou
 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.feature.topic.navigation.TopicRoute
 import com.google.samples.apps.nowinandroid.navigation.TopLevelDestination
 import com.google.samples.apps.nowinandroid.navigation.TopLevelDestination.BOOKMARKS
 import com.google.samples.apps.nowinandroid.navigation.TopLevelDestination.FOR_YOU
@@ -213,7 +214,8 @@ private fun NavigationTrackingSideEffect(navController: NavHostController) {
 class Nav3NavigatorSimple(val navController: NavHostController){
 
     private val migratedRoutes = listOf(
-        BookmarksRoute::class
+        BookmarksRoute::class,
+        TopicRoute::class
     ).associateBy { it.qualifiedName }
 
     // TODO: We are using Dispatchers.Main so that we can access SavedStateHandle in toRoute,
@@ -231,16 +233,17 @@ class Nav3NavigatorSimple(val navController: NavHostController){
                     if (backStack.isNotEmpty()){
                         clear()
                         val entriesToAdd = nav2BackStack.mapNotNull { entry ->
-                            println("Evaluating: ${entry.destination::class.qualifiedName}")
+
+                            val className = entry.destination.route?.substringBefore('/')
+                            println("Evaluating: $className")
                             // Ignore nav graph root entries
                             if (entry.destination::class.qualifiedName == "androidx.navigation.compose.ComposeNavGraphNavigator.ComposeNavGraph"){
                                 null
                             } else {
-                                val migratedRouteClass = migratedRoutes[entry.destination.route]
-                                if (migratedRouteClass != null){
-                                    entry.savedStateHandle.internalToRoute(route = migratedRouteClass, typeMap = emptyMap())
-                                } else {
-                                    entry
+                                when (className) {
+                                    BookmarksRoute::class.qualifiedName -> entry.toRoute<BookmarksRoute>()
+                                    TopicRoute::class.qualifiedName -> entry.toRoute<TopicRoute>()
+                                    else -> entry
                                 }
                             }
                         }

feature/topic/build.gradle.kts

@@ -26,6 +26,7 @@ android {
 
 dependencies {
     implementation(projects.core.data)
+    implementation(projects.core.navigation)
 
     testImplementation(projects.core.testing)
     testImplementation(libs.robolectric)

feature/topic/src/main/kotlin/com/google/samples/apps/nowinandroid/feature/topic/navigation/TopicNavigation.kt

@@ -17,30 +17,21 @@
 package com.google.samples.apps.nowinandroid.feature.topic.navigation
 
 import androidx.hilt.navigation.compose.hiltViewModel
-import androidx.navigation.NavController
-import androidx.navigation.NavGraphBuilder
-import androidx.navigation.NavOptionsBuilder
-import androidx.navigation.compose.composable
-import androidx.navigation.toRoute
+import androidx.navigation3.runtime.EntryProviderBuilder
+import androidx.navigation3.runtime.entry
 import com.google.samples.apps.nowinandroid.feature.topic.TopicScreen
 import com.google.samples.apps.nowinandroid.feature.topic.TopicViewModel
 import kotlinx.serialization.Serializable
 
 @Serializable data class TopicRoute(val id: String)
 
-fun NavController.navigateToTopic(topicId: String, navOptions: NavOptionsBuilder.() -> Unit = {}) {
-    navigate(route = TopicRoute(topicId)) {
-        navOptions()
-    }
-}
-
-fun NavGraphBuilder.topicScreen(
+fun EntryProviderBuilder<Any>.topicScreen(
     showBackButton: Boolean,
     onBackClick: () -> Unit,
     onTopicClick: (String) -> Unit,
 ) {
-    composable<TopicRoute> { entry ->
-        val id = entry.toRoute<TopicRoute>().id
+    entry<TopicRoute> { entry ->
+        val id = entry.id
         TopicScreen(
             showBackButton = showBackButton,
             onBackClick = onBackClick,