Merge pull request #1025 from jbw0033/nested_host

[Navigation Animation] Fix Nested NavHost animations
google · Apr 27, 2022 · b37cd07 · b37cd07
2 parents abb08e5 + d59c882
commit b37cd07
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Showing 2 changed files with 14 additions and 57 deletions.
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
@@ -13,7 +13,7 @@ okhttp = "3.12.13"
 coil = "1.3.2"
 
 androidxtest = "1.4.0"
-androidxnavigation = "2.4.0"
+androidxnavigation = "2.5.0-alpha04"
 
 [libraries]
 compose-ui-ui = { module = "androidx.compose.ui:ui", version.ref = "compose" }

diff --git a/...on-animation/src/main/java/com/google/accompanist/navigation/animation/AnimatedNavHost.kt b/...on-animation/src/main/java/com/google/accompanist/navigation/animation/AnimatedNavHost.kt
@@ -28,17 +28,13 @@ import androidx.compose.animation.fadeIn
 import androidx.compose.animation.fadeOut
 import androidx.compose.animation.with
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateListOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.saveable.rememberSaveableStateHolder
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalLifecycleOwner
-import androidx.lifecycle.Lifecycle
-import androidx.lifecycle.LifecycleEventObserver
 import androidx.lifecycle.viewmodel.compose.LocalViewModelStoreOwner
 import androidx.navigation.NavBackStackEntry
 import androidx.navigation.NavDestination
@@ -52,6 +48,7 @@ import androidx.navigation.compose.DialogNavigator
 import androidx.navigation.compose.LocalOwnersProvider
 import androidx.navigation.createGraph
 import androidx.navigation.get
+import kotlinx.coroutines.flow.map
 
 /**
  * Provides in place in the Compose hierarchy for self contained navigation to occur.
@@ -155,14 +152,16 @@ public fun AnimatedNavHost(
     val composeNavigator = navController.navigatorProvider.get<Navigator<out NavDestination>>(
         AnimatedComposeNavigator.NAME
     ) as? AnimatedComposeNavigator ?: return
-    val backStack by composeNavigator.backStack.collectAsState()
-    val transitionsInProgress by composeNavigator.transitionsInProgress.collectAsState()
-    val visibleTransitionsInProgress = rememberVisibleList(transitionsInProgress)
-    val visibleBackStack = rememberVisibleList(backStack)
-    visibleTransitionsInProgress.PopulateVisibleList(transitionsInProgress)
-    visibleBackStack.PopulateVisibleList(backStack)
+    val visibleEntries by remember(navController.visibleEntries) {
+        navController.visibleEntries.map {
+            it.filter {
+                entry ->
+                entry.destination.navigatorName == AnimatedComposeNavigator.NAME
+            }
+        }
+    }.collectAsState(emptyList())
 
-    val backStackEntry = visibleTransitionsInProgress.lastOrNull() ?: visibleBackStack.lastOrNull()
+    val backStackEntry = visibleEntries.lastOrNull()
 
     if (backStackEntry != null) {
         val finalEnter: AnimatedContentScope<NavBackStackEntry>.() -> EnterTransition = {
@@ -200,20 +199,18 @@ public fun AnimatedNavHost(
             contentAlignment,
             contentKey = { it.id }
         ) {
-            val currentEntry = transitionsInProgress.lastOrNull { entry ->
-                it == entry
-            } ?: backStack.lastOrNull { entry ->
+            val currentEntry = visibleEntries.last { entry ->
                 it == entry
             }
             // while in the scope of the composable, we provide the navBackStackEntry as the
             // ViewModelStoreOwner and LifecycleOwner
-            currentEntry?.LocalOwnersProvider(saveableStateHolder) {
+            currentEntry.LocalOwnersProvider(saveableStateHolder) {
                 (currentEntry.destination as AnimatedComposeNavigator.Destination)
                     .content(this, currentEntry)
             }
         }
         if (transition.currentState == transition.targetState) {
-            transitionsInProgress.forEach { entry ->
+            visibleEntries.forEach { entry ->
                 composeNavigator.markTransitionComplete(entry)
             }
         }
@@ -243,43 +240,3 @@ internal val popEnterTransitions =
 @ExperimentalAnimationApi
 internal val popExitTransitions =
     mutableMapOf<String?, (AnimatedContentScope<NavBackStackEntry>.() -> ExitTransition?)?>()
-
-@Composable
-private fun MutableList<NavBackStackEntry>.PopulateVisibleList(
-    transitionsInProgress: Collection<NavBackStackEntry>
-) {
-    transitionsInProgress.forEach { entry ->
-        DisposableEffect(entry.lifecycle) {
-            val observer = LifecycleEventObserver { _, event ->
-                // ON_START -> add to visibleBackStack, ON_STOP -> remove from visibleBackStack
-                if (event == Lifecycle.Event.ON_START) {
-                    // We want to treat the visible lists as Sets but we want to keep
-                    // the functionality of mutableStateListOf() so that we recompose in response
-                    // to adds and removes.
-                    if (!contains(entry)) {
-                        add(entry)
-                    }
-                }
-                if (event == Lifecycle.Event.ON_STOP) {
-                    remove(entry)
-                }
-            }
-            entry.lifecycle.addObserver(observer)
-            onDispose {
-                entry.lifecycle.removeObserver(observer)
-            }
-        }
-    }
-}
-
-@Composable
-private fun rememberVisibleList(transitionsInProgress: Collection<NavBackStackEntry>) =
-    remember(transitionsInProgress) {
-        mutableStateListOf<NavBackStackEntry>().also {
-            it.addAll(
-                transitionsInProgress.filter { entry ->
-                    entry.lifecycle.currentState.isAtLeast(Lifecycle.State.STARTED)
-                }
-            )
-        }
-    }