Address Dany's feedback

Author: dturner

app/src/main/java/com/example/nav3recipes/modular/AppModule.kt

@@ -1,20 +1,16 @@
 package com.example.nav3recipes.modular
 
-import androidx.compose.runtime.snapshots.SnapshotStateList
 import dagger.Module
 import dagger.Provides
 import dagger.hilt.InstallIn
 import dagger.hilt.android.components.ActivityRetainedComponent
 import dagger.hilt.android.scopes.ActivityRetainedScoped
-import javax.inject.Singleton
 
 @Module
 @InstallIn(ActivityRetainedComponent::class)
 object AppModule {
 
     @Provides
     @ActivityRetainedScoped
-    fun provideBackStack(backStackFactory: BackStackFactory) : SnapshotStateList<Any> =
-        backStackFactory.create(startDestination = ConversationList)
-
+    fun provideNavigator() : Navigator = Navigator(startDestination = ConversationList)
 }

app/src/main/java/com/example/nav3recipes/modular/CommonModule.kt

@@ -14,6 +14,14 @@ import javax.inject.Inject
 typealias EntryProviderInstaller = EntryProviderBuilder<Any>.() -> Unit
 
 @ActivityRetainedScoped
-class BackStackFactory @Inject constructor() {
-    fun create(startDestination: Any) : SnapshotStateList<Any> = mutableStateListOf(startDestination)
-}
+class Navigator @Inject constructor(startDestination: Any) {
+    val backStack : SnapshotStateList<Any> = mutableStateListOf(startDestination)
+
+    fun goTo(destination: Any){
+        backStack.add(destination)
+    }
+
+    fun goBack(){
+        backStack.removeLastOrNull()
+    }
+}

app/src/main/java/com/example/nav3recipes/modular/ConversationModule.kt

@@ -43,17 +43,17 @@ object ConversationModule {
 
     @IntoSet
     @Provides
-    fun provideEntryProviderInstaller(backStack: SnapshotStateList<Any>): EntryProviderInstaller =
+    fun provideEntryProviderInstaller(navigator: Navigator): EntryProviderInstaller =
         {
             entry<ConversationList> {
                 ConversationListScreen(
                     onConversationClicked = { conversationDetail ->
-                        backStack.add(conversationDetail)
+                        navigator.goTo(conversationDetail)
                     }
                 )
             }
             entry<ConversationDetail> { key ->
-                ConversationDetailScreen(key) { backStack.add(Profile) }
+                ConversationDetailScreen(key) { navigator.goTo(Profile) }
             }
         }
 }

app/src/main/java/com/example/nav3recipes/modular/ModularActivity.kt

@@ -22,15 +22,16 @@ import javax.inject.Inject
  * - api: defines the public facing routes for this feature
  * - impl: defines the entryProviders for this feature, these are injected into the app's main activity
  * The common module defines:
- * - how the back stack should be created
+ * - a common navigator class that exposes a back stack and methods to modify that back stack
  * - a type that should be used by feature modules to inject entryProviders into the app's main activity
- * The app module creates the back stack by supplying a start destination and provides this back stack to the rest of the app module (i.e. MainActivity) and the feature modules. 
+ * The app module creates the navigator by supplying a start destination and provides this navigator
+ * to the rest of the app module (i.e. MainActivity) and the feature modules.
  */
 @AndroidEntryPoint
 class ModularActivity : ComponentActivity() {
 
     @Inject
-    lateinit var backStack: SnapshotStateList<Any>
+    lateinit var navigator: Navigator
 
     @Inject
     lateinit var entryProviderBuilders: Set<@JvmSuppressWildcards EntryProviderInstaller>
@@ -41,9 +42,9 @@ class ModularActivity : ComponentActivity() {
         setContent {
             Scaffold { paddingValues ->
                 NavDisplay(
-                    backStack = backStack,
+                    backStack = navigator.backStack,
                     modifier = Modifier.padding(paddingValues),
-                    onBack = { backStack.removeLastOrNull() },
+                    onBack = { navigator.goBack() },
                     entryProvider = entryProvider {
                         entryProviderBuilders.forEach { builder -> this.builder() }
                     }

app/src/main/java/com/example/nav3recipes/modular/ProfileModule.kt

@@ -29,7 +29,7 @@ object ProfileModule {
 
     @IntoSet
     @Provides
-    fun provideEntryProviderInstaller(backStack: SnapshotStateList<Any>) : EntryProviderInstaller = {
+    fun provideEntryProviderInstaller() : EntryProviderInstaller = {
         entry<Profile>{
             ProfileScreen()
         }