기능 모듈과 핵심 모듈

두 가지 모듈

기능 모듈의 구성

// feature/profile/ProfileScreen.kt
@Composable
fun ProfileScreen(viewModel: ProfileViewModel = hiltViewModel()) {
    val state by viewModel.uiState.collectAsStateWithLifecycle()
    when (state) {
        is ProfileUiState.Loading -> CircularProgressIndicator()
        is ProfileUiState.Success -> ProfileContent((state as ProfileUiState.Success).user)
        is ProfileUiState.Error -> ErrorMessage()
    }
}

기능 ViewModel

// feature/profile/ProfileViewModel.kt
@HiltViewModel
class ProfileViewModel @Inject constructor(
    private val userRepository: UserRepository // from :core:data
) : ViewModel() {
    val uiState: StateFlow<ProfileUiState> =
        userRepository.observeUser()
            .map { ProfileUiState.Success(it) }
            .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5000), ProfileUiState.Loading)
}

핵심 모듈의 구성

// core/model/User.kt
data class User(
    val id: String,
    val name: String,
    val avatarUrl: String
)

디자인 시스템 모듈

// core/designsystem/AppTheme.kt
@Composable
fun AppTheme(
    darkTheme: Boolean = isSystemInDarkTheme(),
    content: @Composable () -> Unit
) {
    val colors = if (darkTheme) DarkColors else LightColors
    MaterialTheme(
        colorScheme = colors,
        typography = AppTypography,
        content = content
    )
}

데이터 모듈이 저장소를 소유합니다

// core/data/UserRepository.kt
interface UserRepository {
    fun observeUser(): Flow<User>
    suspend fun refresh()
}

// core/data/OfflineFirstUserRepository.kt
internal class OfflineFirstUserRepository @Inject constructor(
    private val api: UserApi,        // :core:network
    private val dao: UserDao         // :core:database
) : UserRepository {
    override fun observeUser(): Flow<User> = dao.observe().map { it.toUser() }
    override suspend fun refresh() { dao.upsert(api.fetch().toEntity()) }
}

model과 designsystem을 가볍게 유지하기

// core/model/build.gradle.kts
plugins {
    id("myapp.jvm.library") // pure Kotlin, no Android
}
// No Retrofit, no Room, no Compose here — just data classes

얇은 :app 모듈

// app/MainActivity.kt
@AndroidEntryPoint
class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            AppTheme {            // from :core:designsystem
                AppNavHost()      // routes into :feature:* screens
            }
        }
    }
}

좋은 경계 만들기

선택 사항: api와 impl 분리

// Other features see only the contract, not the screens
// feature/home depends on :feature:profile:api
interface ProfileEntry {
    val route: String
    fun NavGraphBuilder.register(navController: NavController)
}

그래프 구성하기

// :app           -> :feature:home, :feature:profile
// :feature:home  -> :core:data, :core:designsystem
// :feature:profile -> :core:data, :core:designsystem
// :core:data     -> :core:network, :core:database, :core:model
// :core:network  -> :core:model
// :core:database -> :core:model
// :core:model    -> (nothing)

빠른 확인

복습: 기능 및 핵심 모듈