Dagger Hilt：如果没有 @Provides 注释的方法，则无法提供

Question

当我在视图模型中使用如下所示的界面时

class MainViewModel @ViewModelInject constructor(
    private val trafficImagesRepository: TrafficImageRepository, <----------------- Not working
    @Assisted private val savedStateHandle: SavedStateHandle
) : ViewModel() 

我收到如下错误

cannot be provided without an @Provides-annotated method.
  public abstract static class SingletonC implements MainApplication_GeneratedInjector,

我的界面如下

interface TrafficImageRepository {
    suspend fun getTrafficImages() : NetworkResponse<TrafficData, ErrorTrafficImages>
}

Repository 类如下所示

class DefaultTrafficImagesRepository @Inject constructor(private val trafficImageService: TrafficImageService) : TrafficImageRepository {

    override suspend fun getTrafficImages(): NetworkResponse<TrafficData, ErrorTrafficImages> {
        lateinit var response: NetworkResponse<TrafficData, ErrorTrafficImages>
        withContext(IO) {
            val currentTimestamp = Constants.getCurrentTime()
            response = trafficImageService.getTrafficImages(currentTimestamp)
        }
        return response
    }
}

但是，当我直接使用 DefaultTrafficImagesRepository 类而不是 Interface 时，我的应用程序能够构建而不会出现任何错误。

class MainViewModel @ViewModelInject constructor(
    private val trafficImagesRepository: DefaultTrafficImagesRepository , <----------------- Working Fine
    @Assisted private val savedStateHandle: SavedStateHandle
) : ViewModel()

Answer 1

必须绑定接口

@Module
@InstallIn(ViewModelComponent::class)
abstract class RepositoryModule {

    @Binds
    abstract fun bindRepository(impl: DefaultTrafficImagesRepository): TrafficImageRepository 
}

并以这种方式使用 viewmodel 注入

@HiltViewModel
class MainViewModel @Inject constructor(
    private val trafficImagesRepository: TrafficImageRepository,
    @Assisted private val savedStateHandle: SavedStateHandle
) : ViewModel()