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Version: 4.2

Android Module Loading

This guide covers Android-specific module loading with androidContext() and androidLogger().

info

For core module concepts (declaration, includes, overrides), see Modules. For lazy module loading, see Lazy Modules.

Starting Koin on Android​

With Annotations​

@KoinApplication
class MainApplication : Application() {

    override fun onCreate() {
        super.onCreate()

        startKoin<MainApplication> {
            androidLogger()
            androidContext(this@MainApplication)
        }
    }
}

With DSL​

class MainApplication : Application() {

    override fun onCreate() {
        super.onCreate()

        startKoin {
            // Android logger
            androidLogger()
            // or with level
            androidLogger(Level.DEBUG)

            // Android context
            androidContext(this@MainApplication)

            // Modules
            modules(appModule, networkModule, dataModule)
        }
    }
}

Android-Specific Functions​

FunctionDescription
androidContext()Provides Application context in definitions
androidApplication()Provides Application instance in definitions
androidLogger()Android Logcat logger for Koin

Using Android Context​

val androidModule = module {
    single { DatabaseHelper(androidContext()) }
    single { SharedPrefsManager(androidContext()) }
    single { NotificationHelper(androidApplication()) }
}

Dynamic Module Loading​

Load or unload modules at runtime based on Activity lifecycle:

class FeatureActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        // Load feature-specific dependencies
        loadKoinModules(featureModule)
        super.onCreate(savedInstanceState)
    }

    override fun onDestroy() {
        super.onDestroy()
        // Clean up when leaving feature
        unloadKoinModules(featureModule)
    }
}

Use Cases​

  • Premium features - Load only when user has subscription
  • Debug tools - Load only in debug builds
  • Optional features - Load on-demand
// Premium feature module
val premiumModule = module {
    viewModel<PremiumViewModel>()
    single<PremiumRepository>()
}

class PremiumActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        if (userHasPremium()) {
            loadKoinModules(premiumModule)
        }
        super.onCreate(savedInstanceState)
    }
}

Lazy Loading on Android​

For background module loading, use lazy modules:

class MainApplication : Application() {
    override fun onCreate() {
        super.onCreate()

        startKoin {
            androidLogger()
            androidContext(this@MainApplication)

            // Critical modules load immediately
            modules(coreModule)

            // Non-critical modules load in background
            lazyModules(analyticsModule, syncModule)
        }
    }
}
info

For complete lazy modules documentation including parallel loading, see Lazy Modules.

Next Steps​