koin

Name: koin
Author: rcosteira79

37installs13forks

How to install koin?

rcosteira79/android-skills/koin

$npx -y skills add rcosteira79/android-skills --skill koin

Installs into the current project.

Summary

Use when setting up or working with Koin in Android or KMP projects — module declarations with Classic DSL or KSP annotations, ViewModel injection in Compose, scopes, Nav 3 entry providers, application startup, and compile-time verification via verify(). Triggers on Koin, `sing

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SKILL.md

1	# Koin Dependency Injection (Android and KMP)
2
3	Pragmatic Kotlin DI. Koin vs Hilt: Koin runs in `commonMain` (Hilt doesn't) and verifies the graph via `verify()` instead of codegen; Hilt is Android-only with codegen + deep Jetpack integration (`@HiltViewModel` / `hiltViewModel()`). This reference covers the traps and boundaries, not the Classic DSL basics (`single` / `factory` / `scoped` / `viewModel { }` with `get()` resolution and runtime params, `koinViewModel` / `koinInject`, `startKoin { androidLogger(); androidContext(this@MyApp); modules(...) }`). Related: `android-skills:kmp-ktor`, `android-skills:android-data-layer`. Deps via `koin-bom`: `koin-core`, `koin-android`, `koin-androidx-compose`, `koin-compose-viewmodel` (KMP), `koin-compose-viewmodel-navigation` (Nav 3), `koin-test`, + optional `koin-annotations` / `koin-ksp-compiler`.
4
5	## KSP Annotations — the generated-module accessor
6
7	`@Module @ComponentScan` discovers annotated classes and emits a module you pass to `startKoin` as `UserModule().module` — the generated `.module` extension on the annotated class is the part most often missed. Pick one style per module (don't mix Classic DSL + annotations inside a single module; switching between modules is fine).
8
9	```kotlin
10	@Single class UserRepositoryImpl(private val service: UserService) : UserRepository
11	@Factory class UserFormValidator
12	@KoinViewModel class UserDetailViewModel(
13	@InjectedParam private val userId: String,
14	private val repository: UserRepository,
15	) : ViewModel()
16	@Module @ComponentScan("com.example.feature.user") class UserModule
17	// startKoin { modules(UserModule().module) }
18	```
19
20	## KMP source-set layout
21
22	Most bindings live in `commonMain`; platform-typed ones (HTTP engine, `Context`, Keychain) go behind `expect val platformModule: Module` with an `actual` per platform (mirrors `android-skills:kmp-ktor`'s engine pattern). iOS startup: call `InitKoinKt.doInitKoin(config: nil)` from `iOSApp.init()` — Swift reserves `init`, hence the `do` prefix.
23
24	```kotlin
25	// commonMain
26	expect val platformModule: Module
27	// androidMain: actual = module { single<HttpClientEngine> { OkHttp.create() }; single<TokenStorage> { DataStoreTokenStorage(get()) } }
28	// iosMain: actual = module { single<HttpClientEngine> { Darwin.create() }; single<TokenStorage> { KeychainTokenStorage() } }
29	```
30
31	## Compose: the call-site failure
32
33	`koinViewModel` / `koinInject` require `koin-androidx-compose` (Android) or `koin-compose-viewmodel` (KMP). Without that artifact the call compiles but fails at the call site — `koin-core` knows nothing about `ViewModel` or the Compose runtime. For testability, default composable params to `koinInject()`: `fun Screen(service: AnalyticsService = koinInject())`.
34
35	```kotlin
36	val vm: UserDetailViewModel = koinViewModel { parametersOf(userId) }
37	// keyed per entity: koinViewModel(key = "detail_$userId", parameters = { parametersOf(userId) })
38	```
39
40	## Scopes
41
42	Survives configuration changes (the common case) → `activityRetainedScope` — backed by the Activity's retained `ViewModel`, so it lives across rotation and closes on real finish. Declare with `activityRetainedScope { }` (or `@ActivityRetainedScope`) and access via `AndroidScopeComponent`; do not hand-roll `createScope` / `close` for this case.
43
44	```kotlin
45	val checkoutModule = module {
46	activityRetainedScope { // retained across config changes
47	scoped { CheckoutCart() }
48	scoped { CheckoutPricing(get()) }
49	}
50	}
51	class CheckoutActivity : AppCompatActivity(), AndroidScopeComponent {
52	override val scope: Scope by activityRetainedScope()
53	private val cart: CheckoutCart by inject()
54	}
55	```
56
57	Custom lifetime not tied to an Activity (e.g. a multi-step flow keyed by an order id) → declare a `scope<T>` and own its lifecycle: `getKoin().createScope<CheckoutFlow>("checkout-$orderId")`, resolve with `scope.get()`, and `scope.close()` when the flow ends.
58
59	## Nav 3
60
61	`koinEntryProvider()` resolves ViewModels per destination; register destinations inside modules, not inline at the `NavDisplay` site.
62
63	```kotlin
64	val navigationModule = module {
65	navigation<HomeRoute> { HomeScreen(viewModel = koinViewModel()) }
66	navigation<DetailRoute> { route -> DetailScreen(viewModel = koinViewModel { parametersOf(route.id) }) }
67	}
68	NavDisplay(backStack = backStack, onBack = { backStack.removeLastOrNull() }, entryProvider = koinEntryProvider())
69	```
70
71	## Testing — `verify()` / `checkModules()`
72
73	Walks each declaration's constructor and confirms every dependency is declared — missing bindings become **tes

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koin

37installs13forks

View on GitHub

How to install koin?

rcosteira79/android-skills/koin

$npx -y skills add rcosteira79/android-skills --skill koin

Installs into the current project.

Summary

Files · 1

View on GitHub

SKILL.md

1	# Koin Dependency Injection (Android and KMP)
2
3	Pragmatic Kotlin DI. Koin vs Hilt: Koin runs in `commonMain` (Hilt doesn't) and verifies the graph via `verify()` instead of codegen; Hilt is Android-only with codegen + deep Jetpack integration (`@HiltViewModel` / `hiltViewModel()`). This reference covers the traps and boundaries, not the Classic DSL basics (`single` / `factory` / `scoped` / `viewModel { }` with `get()` resolution and runtime params, `koinViewModel` / `koinInject`, `startKoin { androidLogger(); androidContext(this@MyApp); modules(...) }`). Related: `android-skills:kmp-ktor`, `android-skills:android-data-layer`. Deps via `koin-bom`: `koin-core`, `koin-android`, `koin-androidx-compose`, `koin-compose-viewmodel` (KMP), `koin-compose-viewmodel-navigation` (Nav 3), `koin-test`, + optional `koin-annotations` / `koin-ksp-compiler`.
4
5	## KSP Annotations — the generated-module accessor
6
7	`@Module @ComponentScan` discovers annotated classes and emits a module you pass to `startKoin` as `UserModule().module` — the generated `.module` extension on the annotated class is the part most often missed. Pick one style per module (don't mix Classic DSL + annotations inside a single module; switching between modules is fine).
8
9	```kotlin
10	@Single class UserRepositoryImpl(private val service: UserService) : UserRepository
11	@Factory class UserFormValidator
12	@KoinViewModel class UserDetailViewModel(
13	@InjectedParam private val userId: String,
14	private val repository: UserRepository,
15	) : ViewModel()
16	@Module @ComponentScan("com.example.feature.user") class UserModule
17	// startKoin { modules(UserModule().module) }
18	```
19
20	## KMP source-set layout
21
22	Most bindings live in `commonMain`; platform-typed ones (HTTP engine, `Context`, Keychain) go behind `expect val platformModule: Module` with an `actual` per platform (mirrors `android-skills:kmp-ktor`'s engine pattern). iOS startup: call `InitKoinKt.doInitKoin(config: nil)` from `iOSApp.init()` — Swift reserves `init`, hence the `do` prefix.
23
24	```kotlin
25	// commonMain
26	expect val platformModule: Module
27	// androidMain: actual = module { single<HttpClientEngine> { OkHttp.create() }; single<TokenStorage> { DataStoreTokenStorage(get()) } }
28	// iosMain: actual = module { single<HttpClientEngine> { Darwin.create() }; single<TokenStorage> { KeychainTokenStorage() } }
29	```
30
31	## Compose: the call-site failure
32
33	`koinViewModel` / `koinInject` require `koin-androidx-compose` (Android) or `koin-compose-viewmodel` (KMP). Without that artifact the call compiles but fails at the call site — `koin-core` knows nothing about `ViewModel` or the Compose runtime. For testability, default composable params to `koinInject()`: `fun Screen(service: AnalyticsService = koinInject())`.
34
35	```kotlin
36	val vm: UserDetailViewModel = koinViewModel { parametersOf(userId) }
37	// keyed per entity: koinViewModel(key = "detail_$userId", parameters = { parametersOf(userId) })
38	```
39
40	## Scopes
41
42	Survives configuration changes (the common case) → `activityRetainedScope` — backed by the Activity's retained `ViewModel`, so it lives across rotation and closes on real finish. Declare with `activityRetainedScope { }` (or `@ActivityRetainedScope`) and access via `AndroidScopeComponent`; do not hand-roll `createScope` / `close` for this case.
43
44	```kotlin
45	val checkoutModule = module {
46	activityRetainedScope { // retained across config changes
47	scoped { CheckoutCart() }
48	scoped { CheckoutPricing(get()) }
49	}
50	}
51	class CheckoutActivity : AppCompatActivity(), AndroidScopeComponent {
52	override val scope: Scope by activityRetainedScope()
53	private val cart: CheckoutCart by inject()
54	}
55	```
56
57	Custom lifetime not tied to an Activity (e.g. a multi-step flow keyed by an order id) → declare a `scope<T>` and own its lifecycle: `getKoin().createScope<CheckoutFlow>("checkout-$orderId")`, resolve with `scope.get()`, and `scope.close()` when the flow ends.
58
59	## Nav 3
60
61	`koinEntryProvider()` resolves ViewModels per destination; register destinations inside modules, not inline at the `NavDisplay` site.
62
63	```kotlin
64	val navigationModule = module {
65	navigation<HomeRoute> { HomeScreen(viewModel = koinViewModel()) }
66	navigation<DetailRoute> { route -> DetailScreen(viewModel = koinViewModel { parametersOf(route.id) }) }
67	}
68	NavDisplay(backStack = backStack, onBack = { backStack.removeLastOrNull() }, entryProvider = koinEntryProvider())
69	```
70
71	## Testing — `verify()` / `checkModules()`
72
73	Walks each declaration's constructor and confirms every dependency is declared — missing bindings become **tes

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