Added keySaver property to ComposeNavigator

navigation-compose/src/androidMain/kotlin/com.chrynan.navigation.compose/AndroidNavContainer.kt

@@ -2,17 +2,17 @@ package com.chrynan.navigation.compose
 
 import androidx.activity.compose.BackHandler
 import androidx.compose.foundation.layout.Box
-import androidx.compose.runtime.Composable
-import androidx.compose.runtime.collectAsState
-import androidx.compose.runtime.getValue
-import androidx.compose.runtime.saveable.autoSaver
+import androidx.compose.runtime.*
+import androidx.compose.runtime.saveable.rememberSaveable
 
 @Composable
 @ExperimentalNavigationApi
 internal actual fun <Context, Key> InternalNavContainer(
     navigator: BaseComposeNavigatorByContentViewModel<Context, Key>
 ) {
-    val contentKey by navigator.keyChanges.collectAsState(initial = navigator.initialKey)
+    val contentKey = rememberSaveable(navigator.keySaver) { mutableStateOf(navigator.initialKey) }
+
+    navigator.keyChanges.collectAsStateIn(state = contentKey)
 
     val scope = object : ComposeNavigationContentScope<Key> {
 
@@ -21,7 +21,7 @@ internal actual fun <Context, Key> InternalNavContainer(
 
     Box {
         navigator.apply {
-            scope.content(contentKey)
+            scope.content(contentKey.value)
         }
     }
 
@@ -34,11 +34,13 @@ internal actual fun <Context, Key, NavigationScope : ComposeNavigationKeyScope<K
     navigator: BaseComposeNavigatorByKeyViewModel<Context, Key, NavigationScope>,
     scope: NavigationScope
 ) {
-    val contentKey by navigator.keyChanges.collectAsState(initial = navigator.initialKey)
+    val contentKey = rememberSaveable(navigator.keySaver) { mutableStateOf(navigator.initialKey) }
+
+    navigator.keyChanges.collectAsStateIn(state = contentKey)
 
     Box {
         navigator.apply {
-            scope.content(contentKey)
+            scope.content(contentKey.value)
         }
     }
 

navigation-compose/src/commonMain/kotlin/com.chrynan.navigation.compose/ComposeNavigationIntentNavigator.kt

@@ -32,8 +32,10 @@ interface ComposeNavigationIntentStackNavigatorByKey<I : NavigationIntent> :
 class ComposeNavigationIntentNavigatorByKeyViewModel<Context, Intent : NavigationIntent> internal constructor(
     initialScope: Context,
     initialKeys: (Context) -> Intent,
+    keySaver: Saver<Intent, Any>,
     override val content: @Composable ComposeNavigationIntentScope<Intent>.(key: Intent) -> Unit
 ) : BaseComposeNavigatorByKeyViewModel<Context, Intent, ComposeNavigationIntentScope<Intent>>(
     initialContext = initialScope,
-    initialKeys = initialKeys
+    initialKeys = initialKeys,
+    keySaver = keySaver
 ), ComposeNavigationIntentStackNavigatorByKey<Intent>

navigation-compose/src/commonMain/kotlin/com.chrynan.navigation.compose/ComposeNavigator.kt

@@ -8,27 +8,29 @@ import com.chrynan.navigation.NavStackDuplicateContentStrategy
 import com.chrynan.navigation.Navigator
 
 @ExperimentalNavigationApi
-interface ComposeNavigator<T> : Navigator {
+interface ComposeNavigator<Key> : Navigator {
 
-    val initialKey: T
+    val initialKey: Key
 
-    val currentKey: T
+    val currentKey: Key
 
-    val keyChanges: Flow<T>
+    val keyChanges: Flow<Key>
 
     val isInitialized: Boolean
 
+    val keySaver: Saver<Key, Any>
+
     companion object
 }
 
 @ExperimentalNavigationApi
-interface ComposeNavigatorByContent<T> : ComposeNavigator<T> {
+interface ComposeNavigatorByContent<Key> : ComposeNavigator<Key> {
 
     @Composable
     fun goTo(
-        key: T,
+        key: Key,
         strategy: NavStackDuplicateContentStrategy,
-        content: @Composable ComposeNavigationContentScope<T>.() -> Unit
+        content: @Composable ComposeNavigationContentScope<Key>.() -> Unit
     )
 
     companion object
@@ -38,14 +40,14 @@ interface ComposeNavigatorByContent<T> : ComposeNavigator<T> {
 @Suppress("unused")
 @ExperimentalNavigationApi
 @Composable
-fun <T> ComposeNavigatorByContent<T>.goTo(key: T, content: @Composable ComposeNavigationContentScope<T>.() -> Unit) =
+fun <Key> ComposeNavigatorByContent<Key>.goTo(key: Key, content: @Composable ComposeNavigationContentScope<Key>.() -> Unit) =
     goTo(key = key, strategy = NavStackDuplicateContentStrategy.CLEAR_STACK, content = content)
 
 @ExperimentalNavigationApi
-interface ComposeNavigatorByKey<T> : ComposeNavigator<T> {
+interface ComposeNavigatorByKey<Key> : ComposeNavigator<Key> {
 
     fun goTo(
-        key: T,
+        key: Key,
         strategy: NavStackDuplicateContentStrategy
     )
 
@@ -55,11 +57,11 @@ interface ComposeNavigatorByKey<T> : ComposeNavigator<T> {
 // Note: This is needed because defaults aren't working for @Composable functions for interfaces.
 @Suppress("unused")
 @ExperimentalNavigationApi
-fun <T> ComposeNavigatorByKey<T>.goTo(key: T) =
+fun <Key> ComposeNavigatorByKey<Key>.goTo(key: Key) =
     goTo(key = key, strategy = NavStackDuplicateContentStrategy.CLEAR_STACK)
 
 @ExperimentalNavigationApi
-interface ComposeStackNavigator<T> : ComposeNavigator<T> {
+interface ComposeStackNavigator<Key> : ComposeNavigator<Key> {
 
     fun canGoBack(): Boolean
 
@@ -69,15 +71,15 @@ interface ComposeStackNavigator<T> : ComposeNavigator<T> {
 }
 
 @ExperimentalNavigationApi
-interface ComposeStackNavigatorByContent<T> : ComposeStackNavigator<T>,
-    ComposeNavigatorByContent<T> {
+interface ComposeStackNavigatorByContent<Key> : ComposeStackNavigator<Key>,
+    ComposeNavigatorByContent<Key> {
 
     companion object
 }
 
 @ExperimentalNavigationApi
-interface ComposeStackNavigatorByKey<T> : ComposeStackNavigator<T>,
-    ComposeNavigatorByKey<T> {
+interface ComposeStackNavigatorByKey<Key> : ComposeStackNavigator<Key>,
+    ComposeNavigatorByKey<Key> {
 
     companion object
 }

navigation-compose/src/commonMain/kotlin/com.chrynan.navigation.compose/ComposeNavigatorByContentViewModel.kt

@@ -21,6 +21,7 @@ abstract class BaseComposeNavigatorByContentViewModel<Context, Key> : ViewModel(
 @ExperimentalNavigationApi
 class ComposeNavigatorByContentViewModel<Context, Key> internal constructor(
     override val initialContext: Context,
+    override val keySaver: Saver<Key, Any>,
     private val initialKeysAndContent: (Context) -> Pair<Key, @Composable ComposeNavigationContentScope<Key>.() -> Unit>
 ) : BaseComposeNavigatorByContentViewModel<Context, Key>() {
 

navigation-compose/src/commonMain/kotlin/com.chrynan.navigation.compose/ComposeNavigatorByKeyViewModel.kt

@@ -10,6 +10,7 @@ import kotlinx.coroutines.flow.filterNotNull
 @ExperimentalNavigationApi
 abstract class BaseComposeNavigatorByKeyViewModel<Context, Key, NavigationScope : ComposeNavigationKeyScope<Key>>(
     final override val initialContext: Context,
+    final override val keySaver: Saver<Key, Any>,
     private val initialKeys: (Context) -> Key
 ) : ViewModel(),
     ComposeNavigator<Key>,
@@ -110,10 +111,12 @@ abstract class BaseComposeNavigatorByKeyViewModel<Context, Key, NavigationScope
 
 @ExperimentalNavigationApi
 class ComposeNavigatorByKeyViewModel<Context, Key> internal constructor(
-    initialScope: Context,
+    initialContext: Context,
     initialKeys: (Context) -> Key,
+    keySaver: Saver<Key, Any>,
     override val content: @Composable ComposeNavigationKeyScope<Key>.(key: Key) -> Unit
 ) : BaseComposeNavigatorByKeyViewModel<Context, Key, ComposeNavigationKeyScope<Key>>(
-    initialContext = initialScope,
-    initialKeys = initialKeys
+    initialContext = initialContext,
+    initialKeys = initialKeys,
+    keySaver = keySaver
 )

navigation-compose/src/commonMain/kotlin/com.chrynan.navigation.compose/FlowStateUtils.kt

@@ -0,0 +1,84 @@
+@file:Suppress("unused")
+
+package com.chrynan.navigation.compose
+
+import androidx.compose.runtime.*
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.suspendCancellableCoroutine
+import kotlinx.coroutines.withContext
+import kotlin.coroutines.CoroutineContext
+import kotlin.coroutines.EmptyCoroutineContext
+import kotlin.experimental.ExperimentalTypeInference
+
+/**
+ * Similar to the [collectAsState] function but allows providing the [MutableState] to be used.
+ *
+ * @see [collectAsState]
+ */
+@Composable
+internal fun <T : R, R> Flow<T>.collectAsStateIn(
+    state: MutableState<R>,
+    context: CoroutineContext = EmptyCoroutineContext
+): State<R> = produceStateIn(state = state, this, context) {
+    if (context == EmptyCoroutineContext) {
+        collect { value = it }
+    } else withContext(context) {