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Start Koin on Android

The koin-android project is dedicated to provide Koin powers to Android world. See the Android setup section for more details.

From your Application class​

From your Application class you can use the startKoin function and inject the Android context with androidContext as follows:

class MainApplication : Application() {

    override fun onCreate() {
        super.onCreate()

        startKoin {
            // Log Koin into Android logger
            androidLogger()
            // Reference Android context
            androidContext(this@MainApplication)
            // Load modules
            modules(myAppModules)
        }
    }
}
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You can also start Koin from anywhere if you don't want to start it from your Application class.

If you need to start Koin from another Android class, you can use the startKoin function and provide your Android Context instance with just like:

startKoin {
    //inject Android context
    androidContext(/* your android context */)
    // ...
}

Extra Configurations​

From your Koin configuration (in startKoin { } block code), you can also configure several parts of Koin.

Koin Logging for Android​

Within your KoinApplication instance, we have an extension androidLogger which uses the AndroidLogger() class. This logger is an Android implementation of the Koin logger.

Up to you to change this logger if it doesn't suit to your needs.

startKoin {
    // use Android logger - Level.INFO by default
    androidLogger()
    // ...
}

Loading Properties​

You can use Koin properties in the assets/koin.properties file, to store keys/values:

startKoin {
    // ...
    // use properties from assets/koin.properties
    androidFileProperties()   
}

Start Koin with Androidx Startup (4.0.1)​

By using Gradle packge koin-androidx-startup, we can use KoinStartup interface to declare your Koin configuration your Application class:

class MainApplication : Application(),KoinStartup {

     override fun onKoinStartup(): KoinAppDeclaration = {
        androidContext(this@MainApplication)
        modules(appModule)
    }

    override fun onCreate() {
        super.onCreate()
    }
}

This replaces the startKoin function that is usally used in onCreate.

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KoinStartup avoid blocking main thread at for startup time, and offers better performances.

Startup Dependency with Koin​

You can make your Initializer depend on KoinInitializer if you need Koin to be setup, and allow to inject dependencies:

class CrashTrackerInitializer : Initializer<Unit>, KoinComponent {

    private val crashTrackerService: CrashTrackerService by inject()

    override fun create(context: Context) {
        crashTrackerService.configure(context)
    }

    override fun dependencies(): List<Class<out Initializer<*>>> {
        return listOf(KoinInitializer::class.java)
    }

}