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nowinandroid
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Code Issues Projects Releases Wiki Activity

Support nested nav graphs

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dt/nav3-c
Don Turner 2 months ago
parent e196be9ad0
commit 3a40f1b72d
3 changed files with 90 additions and 148 deletions
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5
app/src/main/kotlin/com/google/samples/apps/nowinandroid/navigation/NiaNavHost.kt
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@ -28,7 +28,6 @@ import com.google.samples.apps.nowinandroid.feature.bookmarks.impl.navigation.bo
import com.google.samples.apps.nowinandroid.feature.foryou.navigation.ForYouBaseRoute
import com.google.samples.apps.nowinandroid.feature.foryou.navigation.forYouSection
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.SearchRoute
import com.google.samples.apps.nowinandroid.feature.search.navigation.searchScreen
import com.google.samples.apps.nowinandroid.feature.topic.navigation.TopicRoute
@ -94,7 +93,9 @@ fun NiaNavHost(
searchScreen(
onBackClick = navController::popBackStack,
onInterestsClick = { appState.navigateToTopLevelDestination(INTERESTS) },
onTopicClick = navController::navigateToInterests,
onTopicClick = {
nav3Navigator.goTo(route = InterestsRoute(it))
},
)
interestsListDetailScreen()
},

212
app/src/main/kotlin/com/google/samples/apps/nowinandroid/ui/NiaAppState.kt
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@ -26,6 +26,7 @@ import androidx.compose.runtime.rememberCoroutineScope
import androidx.navigation.NavController
import androidx.navigation.NavDestination
import androidx.navigation.NavDestination.Companion.hasRoute
import androidx.navigation.NavGraph
import androidx.navigation.NavGraph.Companion.findStartDestination
import androidx.navigation.NavHostController
import androidx.navigation.NavOptions
@ -40,7 +41,6 @@ import com.google.samples.apps.nowinandroid.core.ui.TrackDisposableJank
import com.google.samples.apps.nowinandroid.feature.bookmarks.api.navigation.BookmarksRoute
import com.google.samples.apps.nowinandroid.feature.foryou.navigation.navigateToForYou
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.SearchRoute
import com.google.samples.apps.nowinandroid.feature.search.navigation.navigateToSearch
import com.google.samples.apps.nowinandroid.feature.topic.navigation.TopicRoute
@ -48,7 +48,6 @@ 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
import com.google.samples.apps.nowinandroid.navigation.TopLevelDestination.INTERESTS
import com.google.samples.apps.nowinandroid.ui.interests2pane.interestsListDetailScreen
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.Job
@ -188,7 +187,9 @@ class NiaAppState(
when (topLevelDestination) {
FOR_YOU -> navController.navigateToForYou(topLevelNavOptions)
BOOKMARKS -> nav3Navigator.goTo(route = BookmarksRoute, topLevelNavOptions)
INTERESTS -> navController.navigateToInterests(null, topLevelNavOptions)
INTERESTS -> {
nav3Navigator.goTo(route = InterestsRoute(null), topLevelNavOptions)
}
}
}
}
@ -216,172 +217,121 @@ private fun NavigationTrackingSideEffect(navController: NavHostController) {
class Nav3NavigatorSimple(val navController: NavHostController){
private val migratedRoutes = listOf(
BookmarksRoute::class,
TopicRoute::class,
SearchRoute::class,
InterestsRoute::class,
).associateBy { it.qualifiedName }
// TODO: We are using Dispatchers.Main so that we can access SavedStateHandle in toRoute,
// however, this may be unnecessary if we can just deserialize the route from memory
val coroutineScope = CoroutineScope(Job() + Dispatchers.Main)
// We need a single element to avoid "backStack cannot be empty" error b/430023647
val backStack = mutableStateListOf<Any>(Unit)
// Expose the current top level route for consumers
lateinit var topLevelKey : String
// key = top level route string, value = route instance
private var topLevelStacks : LinkedHashMap<String, MutableList<Any>> = linkedMapOf()
init {
coroutineScope.launch {
navController.currentBackStack.collect { nav2BackStack ->
with(backStack) {
println("Nav2 backstack changed, size: ${backStack.size}")
if (backStack.isNotEmpty()){
clear()
val entriesToAdd = nav2BackStack.mapNotNull { entry ->
// Ignore nav graph root entries
if (entry.destination::class.qualifiedName == "androidx.navigation.compose.ComposeNavGraphNavigator.ComposeNavGraph"){
null
} else {
with(entry.destination) {
if (hasRoute<BookmarksRoute>()) { entry.toRoute<BookmarksRoute>() }
else if (hasRoute<TopicRoute>()) { entry.toRoute<TopicRoute>() }
else if (hasRoute<SearchRoute>()) { entry.toRoute<SearchRoute>() }
else if (hasRoute<InterestsRoute>()) { entry.toRoute<InterestsRoute>() }
else { entry }
}
}
}
addAll(entriesToAdd)
println("Nav3 backstack updated: $backStack")
}
}
}
}
}
fun goBack(){
backStack.removeLastOrNull()
navController.popBackStack()
}
topLevelStacks.clear()
fun goTo(route: Any, navOptions: NavOptions? = null){
backStack.add(route)
navController.navigate(route = route, navOptions = navOptions)
}
}
val rootNode : NavGraph = navController.graph
println("Root node start destination: ${rootNode.startDestinationRoute}")
nav2BackStack.forEach { entry ->
println("\n==ENTRY==")
println("Entry: $entry")
println("Destination: ${entry.destination}")
println("Destination navigatorName: ${entry.destination.navigatorName}")
println("Route: ${entry.destination.route}")
println("Parent destination: ${entry.destination.parent}")
/*
class Nav3Navigator<T: Any>(val navController: NavHostController, startRoute: T) {
val destination = entry.destination
// We only care about navigable destinations
if (destination.navigatorName == "composable"){
init {
coroutineScope.launch {
navController.currentBackStack.collect { nav2BackStack ->
println("Nav2 back stack changed")
// TODO: Convert this into a nav3 back stack
for (nav2Entry in nav2BackStack){
println("Destination: ${nav2Entry.destination}")
}
}
println("Entry is a composable")
val parentDestination = destination.parent
val stackName = destination.route
val routeInstance =
if (destination.hasRoute<BookmarksRoute>()) {
entry.toRoute<BookmarksRoute>()
} else if (destination.hasRoute<TopicRoute>()) {
entry.toRoute<TopicRoute>()
} else if (destination.hasRoute<SearchRoute>()) {
entry.toRoute<SearchRoute>()
} else if (destination.hasRoute<InterestsRoute>()) {
entry.toRoute<InterestsRoute>()
} else {
// Non migrated top level route
println("Non migrated route")
entry
}
navController.addOnDestinationChangedListener(
listener = object : NavController.OnDestinationChangedListener {
override fun onDestinationChanged(
controller: NavController,
destination: NavDestination,
arguments: Bundle?,
) {
println("NavController destination changed to $destination")
// TODO: something! Or maybe we just listen to the back stack and mirror it here
if (parentDestination == rootNode){
println("This is a top level route")
// Create a new top level stack, if it doesn't exist already
if (stackName != null && topLevelStacks[stackName] == null){
add(stackName, routeInstance)
}
} else {
println("This is a nested route")
// This is a nested route, add it to the appropriate stack
val startDestinationRoute = parentDestination?.startDestinationRoute
println("Its parent has a start destination route of $startDestinationRoute")
if (startDestinationRoute != null){
if (startDestinationRoute == stackName){
println("This is the start destination, creating new nested stack")
// This is the start destination, create a new stack
add(stackName, routeInstance)
} else {
println("This is not the start destination, adding to nested stack")
// This is not the start destination, just add it to the
// previously created route
add(startDestinationRoute, routeInstance)
}
)
}
// Keep track of the baseRoute - this is the route that is always at the bottom of the stack
private val baseRoute = startRoute
// Maintain a stack for each top level route
private var topLevelStacks : LinkedHashMap<T, SnapshotStateList<T>> = linkedMapOf(
baseRoute to mutableStateListOf(baseRoute)
)
// Expose the current top level route for consumers
var topLevelRoute by mutableStateOf(baseRoute)
private set
// Expose the back stack so it can be rendered by the NavDisplay
val backStack : SnapshotStateList<T> = mutableStateListOf(baseRoute)
private fun updateBackStack() {
backStack.apply {
// TODO: Could this be optimised?
clear()
addAll(topLevelStacks.flatMap { it.value })
}
println("Top level stacks: $topLevelStacks")
println("Backstack state: $backStack")
}
fun goTo(route: T, navOptions: NavOptions? = null){
backStack.add(route)
navController.navigate(route, navOptions)
*//*if (route is NavKey){
if (route is TopLevelRoute){
// Pop everything up to the base route stack
for (existingKey in topLevelStacks.keys.reversed()){
if (existingKey != baseRoute) topLevelStacks.remove(existingKey)
}
if (route != baseRoute) {
topLevelStacks.put(route, mutableStateListOf(route))
updateBackStack()
}
}
}
topLevelRoute = route
fun add(stackName: String, route: Any){
if (topLevelStacks[stackName] == null){
topLevelStacks.put(stackName, mutableListOf(route))
} else {
topLevelStacks[topLevelRoute]?.add(route)
topLevelStacks[stackName]?.add(route)
}
topLevelStacks[topLevelRoute]?.add(route)
topLevelKey = stackName
updateBackStack()
} else {
navController.navigate(route, navOptions)
}*//*
}
*//*
fun removeLast(){
val removedKey = topLevelStacks[topLevelRoute]?.removeLastOrNull()
// If the removed key was a top level key, remove the associated top level stack
topLevelStacks.remove(removedKey)
topLevelRoute = topLevelStacks.keys.last()
updateBackStack()
private fun updateBackStack() {
backStack.apply {
clear()
addAll(topLevelStacks.flatMap { it.value })
}
println("Back stack: $backStack")
}
*//*
fun goBack(){
val removedKey = topLevelStacks[topLevelRoute]?.removeLastOrNull()
val removedKey = topLevelStacks[topLevelKey]?.removeLastOrNull()
// If the removed key was a top level key, remove the associated top level stack
if (removedKey is TopLevelRoute){
topLevelStacks.remove(removedKey)
topLevelRoute = topLevelStacks.keys.last()
}
topLevelKey = topLevelStacks.keys.last()
updateBackStack()
if (removedKey is LegacyRoute){
navController.popBackStack()
}
}
}*/
fun goTo(route: Any, navOptions: NavOptions? = null){
add(topLevelKey, route)
navController.navigate(route = route, navOptions = navOptions)
}
}

9
feature/interests/src/main/kotlin/com/google/samples/apps/nowinandroid/feature/interests/navigation/InterestsNavigation.kt
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@ -16,18 +16,9 @@
package com.google.samples.apps.nowinandroid.feature.interests.navigation
import androidx.navigation.NavController
import androidx.navigation.NavOptions
import kotlinx.serialization.Serializable
@Serializable data class InterestsRoute(
// The ID of the topic which will be initially selected at this destination
val initialTopicId: String? = null,
)
fun NavController.navigateToInterests(
initialTopicId: String? = null,
navOptions: NavOptions? = null,
) {
navigate(route = InterestsRoute(initialTopicId), navOptions)
}

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