Dagger 2 introduces new annotation @Binds. You can use it to simplify @Provides, it turns this:
@Module
class HomeModule {
@Provides
HomeView provideHomeView() {
return new HomeViewImpl();
}
}
Into this:
@Module
abstract class HomeModule {
@Binds
abstract HomeView provideHomeView(HomeViewImpl impl);
}
Can we use @Binds and @Provides together?
Yes, you can use static method.
@Module
public abstract class MainActivityModule {
@Provides
static MainPresenter provideMainPresenter(MainView mainView, ApiService apiService) {
return new MainPresenterImpl(mainView, apiService);
}
@Binds
abstract MainView provideMainView(MainActivity mainActivity);
}
On Kotlin, you can use companion object to achieve the same thing.
@Module
abstract class MainApplicationModule {
@Binds
abstract fun provideApplication(application: Application): Context
@Module
companion object {
@JvmStatic
@Provides
internal fun provideAgeMap(): Map<String, Int> {
return mapOf("Luffy" to 17, "Shanks" to 37)
}
}
}
Verdict
@Binds clearly makes component declaration more succint. There is a slight problem when combining it with @Provides. While both approach works. I would prefer to still use @Provides for the sake of consistency. But you may want to experiment it yourself too feel which one you like better.
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