ApplicationComponent&MainActivity.md

@Component @Singleton
  abstract class ApplicationComponent(
    @get:Provides val context: Context,
- ) : GreetingComponent {
-   abstract val greetingHandlerCreator: (String) -> GreetingHandler
- }
+ ) : GreetingComponent

+ @Component
+ abstract class MainActivityComponent(@Component val parent: ApplicationComponent) {
+   abstract val greetingHandlerCreator: (String) -> GreetingHandler
+ }

  class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
-     val greetingHandler = applicationComponent.greetingHandlerCreator("this is an assisted arg")
+     val greetingHandler = MainActivityComponent::class.create(applicationComponent)
+       .greetingHandlerCreator("this is an assisted arg")