Android Architecture Reference

传统 MVP/MVVM → 推荐 UDF (Unidirectional Data Flow)

// 推荐模式
@HiltViewModel
class TaskViewModel @Inject constructor(
    private val taskRepository: TaskRepository,
) : ViewModel() {
    private val _uiState = MutableStateFlow(TaskUiState())
    val uiState: StateFlow<TaskUiState> = _uiState.asStateFlow()
    
    fun onAction(action: TaskAction) { /* 处理用户操作 */ }
}

app/
├── :core:data           → 数据层（Room DAO、Entity、Repository、离线优先）
├── :core:datastore      → DataStore 偏好存储
├── :core:domain         → 领域层（UseCase）
├── :core:model          → 数据模型
├── :core:network        → 网络层（OkHttp + Retrofit + kotlinx-serialization）
├── :core:ui             → UI 基础组件（主题、导航、通用 Compose）
├── :core:data-test     → 测试数据
├── :core:testing       → 测试工具
├── :sync:work           → WorkManager 后台同步
├── :feature:for_you    → 推荐页 Feature
├── :feature:bookmarks  → 书签 Feature
├── :feature:topic      → 话题 Feature
├── :feature:settings   → 设置 Feature
└── :benchmark           → Macrobenchmark 性能测试

// 1. Application 级模块
@Module
@InstallIn(SingletonComponent::class)
object DataModule {
    @Provides @Singleton
    fun provideDatabase(@ApplicationContext ctx: Context): AppDatabase =
        Room.databaseBuilder(ctx, AppDatabase::class.java, "app.db").build()
}

// 2. ViewModel 注入
@HiltViewModel
class FeatureViewModel @Inject constructor(
    private val repository: FeatureRepository,
) : ViewModel()

// 3. Compose 集成
@Composable
fun FeatureScreen(
    viewModel: FeatureViewModel = hiltViewModel(),
)

@Entity(tableName = "items")
data class Item(
    @PrimaryKey val id: String,
    val title: String,
    val timestamp: Long,
)

@Dao
interface ItemDao {
    @Query("SELECT * FROM items ORDER BY timestamp DESC LIMIT :limit")
    fun getRecent(limit: Int = 20): Flow<List<Item>>
}

@Database(entities = [Item::class], version = 1)
abstract class AppDatabase : RoomDatabase()

// Room 分页
@Query("SELECT * FROM items ORDER BY timestamp DESC")
fun pagingSource(): PagingSource<Int, Item>

// Repository 层
fun getItems(): Flow<PagingData<Item>> = Pager(
    config = PagingConfig(pageSize = 20),
    pagingSourceFactory = { dao.pagingSource() }
).flow

// Preferences DataStore
val Context.dataStore by preferencesDataStore(name = "settings")

// 定义 Worker
@HiltWorker
class SyncWorker @AssistedInject constructor(
    @Assisted ctx: Context,
    @Assisted params: WorkerParameters,
    private val repository: SyncRepository,
) : CoroutineWorker(ctx, params) {
    override suspend fun doWork(): Result {
        return try {
            repository.sync()
            Result.success()
        } catch (e: Exception) {
            Result.retry()
        }
    }
}

// 调度
val request = PeriodicWorkRequestBuilder<SyncWorker>(15, TimeUnit.MINUTES)
    .setConstraints(Constraints(requiredNetworkType = NetworkType.CONNECTED))
    .build()
WorkManager.getInstance(context).enqueue(request)

         /\
        /UI\        10% - Compose UI 测试（少量端到端验证）
       /----\
      / 集成 \      20% - Hilt + Room 集成测试
     /--------\
    /  单元测试  \   70% - Repository / ViewModel 单元测试
   /------------\

@Test
fun `when data loaded, uiState shows items`() = runTest {
    val repo = mockk<FeatureRepository> { coEvery { getItems() } returns flowOf(testItems) }
    val viewModel = FeatureViewModel(repo)
    viewModel.uiState.test {
        assertEquals(expectItemCount, awaitItem().items.size)
    }
}

1. architecture-samples   → 看推荐模式（UDF + StateFlow）
2. nowinandroid           → 看模块化划分、Gradle 配置
3. sunflower              → 看 Room + Paging + WorkManager 组合用法
4. testing-samples        → 看测试如何组织