Dagger-Hilt

[masterj3y]

can we use dagger-hilt instead of anvil? From the text you wrote in the documentation, I thought the @CircuitInject only works with anvil. right?

[JohnBuhanan]

I believe @CircuitInject generates code that will contain an anvil annotation like "@ContributesTo"

Hilt will not know how to interpret "@ContributesTo"

[masterj3y]

So do we need to do it manually if we use hilt? how?

[JohnBuhanan]

I'm not the expert, but I would study the code that is generated by Anvil. I believe it is factories for presenters and ui. These factories are then aggregated via dagger multibindings and used to create a CircuitConfig.
Src: https://slackhq.github.io/circuit/factories/

You should be able to manually create your own factories for every new screen and contribute those to multibindings to create a CircuitConfig.

[jordanterry]

I thought I'd add a comment on how I have tackled this with hilt. Its only basic for the time being but I've been trying Circuit out with a single Activity.

@AndroidEntryPoint
class CircuitActivity : AppCompatActivity {

    @Inject
    lateinit var circuitConfig: CircuitConfig

    
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            CircuitCompositionLocals(circuitConfig) {
                CircuitContent(YourRootScreen())
            }
        }
    }
}

I have one very important module I call the CircuitModule

@Module
@InstallIn(ActivityRetainedComponent::class)
class CircuitModule {
    @Provides
    fun providesCircuitConfig(
        uiFactories: Set<@JvmSuppressWildcards Ui.Factory>,
        presenterFactories: Set<@JvmSuppressWildcards Presenter.Factory>
    ): CircuitConfig {
        return CircuitConfig.Builder().apply {
            addUiFactories(uiFactories)
            addPresenterFactories(presenterFactories)
        }.build()
    }
}

I then contributed the relevant factories as follows from relevant parts of my codebase:

@Module
@InstallIn(ActivityRetainedComponent::class)
interface FeatureModule {
    @Binds
    @IntoSet
    fun bindsScreenPresenterFactory(screenPresenterFactory: ScreenPresenterFactory): Presenter.Factory

    @Binds
    @IntoSet
    fun bindsScreenUiFactory(screenUiFactory: ScreenUiFactory): Ui.Factory
}

I've opted for the ActivityRetainedComponent.

[PaulProject]

I have a problem with this solution
error: @Binds methods' parameter type must be assignable to the return type

CircuitModule:

@Module
@InstallIn(SingletonComponent::class)
interface CircuitModule {

    @Multibinds
    fun presenterFactories(): Set<Presenter.Factory>

    @Multibinds
    fun viewFactories(): Set<Ui.Factory>

    companion object {

        @Provides
        fun provideCircuit(
            presenterFactories: @JvmSuppressWildcards Set<Presenter.Factory>,
            uiFactories: @JvmSuppressWildcards Set<Ui.Factory>,
        ): Circuit {
            return Circuit.Builder()
                .addPresenterFactories(presenterFactories)
                .addUiFactories(uiFactories)
                .build()
        }
    }
}

Feature module

    @Binds
    @IntoSet
    fun bindsCountryListPresenterFactory(impl: CountryListPresenterFactory): Presenter.Factory

    @Binds
    @IntoSet
    fun bindsCountryListUiFactory(impl: CountryListUiFactory): Ui.Factory

[ZacSweers]

We're unlikely to write first-party support for Hilt, but wouldn't be against a PR if there's something in the existing code gen we can make more reusable

[jamiesanson]

I've implemented a quick-and-dirty processor fork which supports code gen for hilt - more or less just spitting out the Hilt equivalent of @ContributeMultibindings.

The smallest change I can think of that'd make the majority of the circuit processor extensible is to have some way of optionally adding the Anvil multibinds annotation on generated factories, disabling it in projects not using Anvil. I've achieved this using a KSP arg, but there are probably more ergonomic ways of switching it.

Is this something Circuit would be open to? Happy to contribute any changes

[ZacSweers]

I'd be game for a PR to make the generated annotation configurable 👍

One thing I'm curious about is how hilt would handle the scope key that we currently look for.

[jamiesanson]

Cool, I'll see if I can whip something up! 👍

I have it working by passing in the component you'd like to install the dependency in, rather than Anvil scope you want the dependency contributed to, which lets me reuse the same annotation. e.g

@CircuitInject(ChooseAlbumScreen::class, SingletonComponent::class)
@Composable
fun ChooseAlbum(...)

Which then generates:

// Usual factory without @ContributeMultibindings, as well as:

@Module
@InstallIn(SingletonComponent::class)
public abstract class ChooseAlbumFactoryModule {
  @Binds
  @IntoSet
  public abstract fun bindChooseAlbumFactory(chooseAlbumFactory: ChooseAlbumFactory): Ui.Factory
}

In practice Hilt components aren't the same as Anvil scopes, so I'm not sure if you'd ever want to scope your factories to anything other than SingletonComponent in the Hilt case

[jamiesanson]

PR here for making generated annotation configurable: #963

[ZacSweers]

Just wanted to close this out that Hilt is now supported thanks to @jamiesanson!