Koin Navigation3 Integration #118

arnaudgiuliani · 2025-11-04T10:02:27Z

This PR proposes Koin Navigation 3 integration usages:

Module navigation entry declaration (within Activity scope) with navigation function:

val profileModule = module {
    activityRetainedScope {
        navigation<Profile> { ProfileScreen() }
    }
}

val conversationModule = module {
    activityRetainedScope {
        navigation<ConversationList> {
            ConversationListScreen(
                onConversationClicked = { conversationDetail ->
                    get<Navigator>().goTo(conversationDetail)
                }
            )
        }

        navigation<ConversationDetail> { key ->
            ConversationDetailScreen(key) {
                get<Navigator>().goTo(Profile)
            }
        }
    }
}

Allow to inject directly the EntryProvider from Activity:

class KoinModularActivity : ComponentActivity(), AndroidScopeComponent {

    override val scope : Scope by activityRetainedScope()
    val navigator: Navigator by inject()

    override fun onCreate(savedInstanceState: Bundle?) {
        // ...

        setContent {
            Scaffold { paddingValues ->
                NavDisplay(
                    backStack = navigator.backStack,
                    modifier = Modifier.padding(paddingValues),
                    onBack = { navigator.goBack() },
                    // inject here
                    entryProvider = getEntryProvider()
                )
            }
        }
    }
}

Key Changes

New Files

KoinModularActivity.kt: Main activity demonstrating Koin-based modular navigation with koin-compose-navigation3 integration
AppModule.kt: Root Koin module that includes feature modules and provides the Navigator
ConversationModule.kt: Feature module with ConversationList and ConversationDetail screens (108 lines)
ProfileModule.kt: Feature module with Profile screen
CommonModule.kt: Shared Navigator class managing navigation backstack

Refactoring

Renamed ModularActivity → HiltModularActivity to distinguish between DI approaches
Updated KoinViewModelsActivity to properly handle Koin lifecycle (prevent multiple instances)

Configuration Updates

Added koin-compose-navigation3 dependency (v4.2.0-alpha1)
Updated Navigation3 to v1.0.0-beta01
Updated Koin to v4.2.0-alpha1
Updated README and RecipePickerActivity to document both DI approaches

Architecture

The implementation follows a modular pattern where:

Features (Conversation, Profile) are defined in separate modules
Each module registers navigation composables using Koin's navigation DSL
A shared Navigator class manages the backstack across features
The main activity uses getEntryProvider() to automatically discover and render navigation entries

google-cla · 2025-11-04T10:02:33Z

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gemini-code-assist · 2025-11-04T10:02:52Z

Summary of Changes

Hello @arnaudgiuliani, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request integrates Koin as a dependency injection framework for modular navigation within the Navigation3 library. It provides a complete example of how to structure an Android application with Koin-driven feature modules, each defining its own navigation entries. This offers developers a clear alternative to the existing Hilt-based modular navigation example, promoting flexibility in DI choices while maintaining a clean, modular architecture.

Highlights

Koin Navigation 3 Integration: Introduced Koin Navigation 3 integration, offering an alternative to Hilt for modular navigation within the Navigation3 library.
Modular Navigation Declaration: Implemented module-based navigation entry declarations using Koin's navigation function within activityRetainedScope for defining screens like Profile and ConversationList.
EntryProvider Injection: Enabled direct injection of EntryProvider from the ComponentActivity (e.g., KoinModularActivity) for seamless navigation setup.
New Koin Modular Architecture Files: Added several new Koin-specific files to demonstrate a modular architecture, including KoinModularActivity.kt, AppModule.kt, ConversationModule.kt, ProfileModule.kt, and CommonModule.kt for a shared Navigator.
Refactoring and Clarity: Refactored the existing Hilt-based modular activity by renaming ModularActivity to HiltModularActivity for better distinction between DI approaches.
Koin Lifecycle Management: Updated Koin initialization logic in KoinViewModelsActivity to explicitly stop any existing Koin instances before starting a new one, preventing multiple Koin contexts.
Dependency Updates: Upgraded koin-compose-navigation3 dependency, Navigation3 to 1.0.0-beta01, and Koin to 4.2.0-alpha1.

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Code Review

This pull request successfully integrates Koin for modular navigation, providing a valuable example alongside the existing Hilt implementation. The new modules and activity are well-structured. My review includes a few suggestions to improve the code. The most important feedback relates to the Koin initialization strategy, which, while functional for this sample app, follows a pattern that is not recommended for production applications. I've also noted a documentation comment that appears to be a copy-paste from the Hilt example and should be corrected for clarity.

gemini-code-assist · 2025-11-04T10:04:26Z

app/src/main/java/com/example/nav3recipes/modular/koin/KoinModularActivity.kt

+        if (KoinPlatform.getKoinOrNull() != null) {
+            stopKoin()
+        }
+        // The startKoin block should be placed in Application.onCreate.
+        startKoin {
+            androidContext(this@KoinModularActivity)
+            modules(appModule)
+        }


Initializing Koin within an Activity's onCreate method, especially with stopKoin(), is not a recommended practice for production applications. It can lead to performance issues and unpredictable behavior if multiple components rely on a stable Koin container. While this approach may be necessary for the isolated nature of these recipe examples, it's crucial to highlight that in a real-world app, startKoin should be called only once, typically in your Application class's onCreate method. Please consider adding a more prominent warning in the KDoc or a code comment to prevent developers from copying this pattern into production code.

this part is to help local sample, of course not advised to to so in normal app setup

gemini-code-assist · 2025-11-04T10:04:26Z

...main/java/com/example/nav3recipes/passingarguments/viewmodels/koin/KoinViewModelsActivity.kt

+        //prevent any already launched Koin instance with other config
+        if (KoinPlatform.getKoinOrNull() != null) {
+            stopKoin()
+        }
        // The startKoin block should be placed in Application.onCreate.
-        if (GlobalContext.getOrNull() == null) {
-            GlobalContext.startKoin {
-                androidContext(this@KoinViewModelsActivity)
-                modules(
-                    module {
-                        viewModelOf(::RouteBViewModel)
-                    }
-                )
-            }
+        startKoin {
+            androidContext(this@KoinViewModelsActivity)
+            modules(
+                module {
+                    viewModelOf(::RouteBViewModel)
+                }
+            )
        }


Similar to the other Koin activity, re-initializing Koin in onCreate by calling stopKoin() and startKoin() is an anti-pattern. This can cause performance degradation and unexpected behavior in a real application where a consistent dependency graph is expected. It's a best practice to initialize Koin once in the Application class. Please add a comment to warn developers against using this pattern in production code.

app/src/main/java/com/example/nav3recipes/modular/koin/KoinModularActivity.kt

…ularActivity.kt Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

arnaudgiuliani · 2025-11-05T11:32:49Z

done CLA update for my profile

pedrofsn

LGTM

xephosbot · 2025-11-06T15:05:51Z

Is it possible to pass metadata to the entry using the new navigation dsl?

danysantiago

LGTM - Thanks!

danysantiago · 2025-11-06T20:25:41Z

app/src/main/java/com/example/nav3recipes/modular/koin/KoinModularActivity.kt

+ * A shared `Navigator` class manages the backstack.
+ *
+ * The `appModule` includes the feature modules, creates the `Navigator` with a start destination,
+ * and makes it available for injection into the `KoinModularActivity` and feature modules.


I would also add one more sentence about how the NavDisplay's is then setup with an EntryProvider from's Koin feature extension koin-compose-navigation3 (i.e. the getEntryProvider Koin function).

arnaudgiuliani added 5 commits October 28, 2025 16:29

setup base usage + fix start

149c1d8

extract extensions for Koin DSL / Integration into Activity

35b26ef

getEntryProvider function

c30e847

Work with koin-compose-navigation3 directly

4790b17

Update README for Koin modular navigation

86830bd

arnaudgiuliani requested review from claraf3, dturner, ianhanniballake and jbw0033 as code owners November 4, 2025 10:02

arnaudgiuliani mentioned this pull request Nov 4, 2025

Feature request: Integration with Nav3 InsertKoinIO/koin#2286

Closed

gemini-code-assist bot reviewed Nov 4, 2025

View reviewed changes

Update app/src/main/java/com/example/nav3recipes/modular/koin/KoinMod…

44a59da

…ularActivity.kt Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

pedrofsn approved these changes Nov 6, 2025

View reviewed changes

danysantiago approved these changes Nov 6, 2025

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arnaudgiuliani commented Nov 4, 2025

Key Changes

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Refactoring

Configuration Updates

Architecture

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