The poor man's Dagger: Exemplifying how to implement dependency injection on Android by (ab)using ApplicationContext's getSystemService(). Here we attain inversion of control without the need of any external library. We also use Kotlin's extension methods to provide a friendlier, strongly-typed API to locate dependencies.

PlacesActivity.kt

class PlacesActivity : AppCompatActivity() {
    private lateinit var placesPresenter: PlacesPresenter

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        // This is how you instantiate your Presenter while the service locator resolves all of its dependencies
        // Note that the explicit type argument <PlacesPresenter> is not even necessary since Kotlin can infer the type
        placesPresenter = application.getSystemService<PlacesPresenter>()
    }
}

ServiceLocatorApplication.kt

class ServiceLocatorApplication : Application() {

    /**
     * Dependency injection using service locator pattern
     */
    override fun getSystemService(name: String?): Any {
        // All this logic can be extracted into a separate "Module" class
        return when (name) {
            // We use the full class' name as the key
            PlacesPresenter::class.java.name -> PlacesPresenter(getSystemService<ILocationRepository>(), getSystemService<IPlacesRepository>())
            ILocationRepository::class.java.name -> GmsLocationRepository(getSystemService<FusedLocationProviderClient>())
            IPlacesRepository::class.java.name -> GmsPlacesRepository(getSystemService<GeoDataClient>())
            FusedLocationProviderClient::class.java.name -> LocationServices.getFusedLocationProviderClient(this)
            GeoDataClient::class.java.name -> Places.getGeoDataClient(this, null)
            else -> super.getSystemService(name)
        }
    }
}

/**
 * Generic strongly-typed extension method for injection
 */
inline fun <reified T : Any> Application.getSystemService() : T {
    // We extract the class name from the generic type
    return this.getSystemService(T::class.java.name) as T
}