UserFeed - Kotlin Multiplatform Mobile

Kotlin Multiplatform (KMP) asosidagi Android va iOS ilova. JSONPlaceholder API dan foydalanuvchilar, postlar va commentlarni yuklab, local bazada saqlaydi. Offline rejimni qo'llab-quvvatlaydi.

Texnologiyalar

Texnologiya	Versiya	Vazifasi
Kotlin Multiplatform	2.3.20	Android + iOS shared code
Jetpack Compose Multiplatform	1.10.3	UI framework
Ktor Client	3.1.3	HTTP so'rovlar
SQLDelight	2.0.2	Local database
Koin	4.0.4	Dependency Injection
Voyager	1.1.0-beta03	Navigation
Kotlinx Coroutines	1.10.2	Asinxron ishlash
Kotlinx Serialization	1.8.1	JSON parsing

API

JSONPlaceholder - public REST API.

Endpoint	Tavsif
GET /users	Barcha foydalanuvchilar
GET /posts?userId={id}	Foydalanuvchi postlari
GET /comments?postId={id}	Post commentlari

Arxitektura

Clean Architecture + MVVM - 3 qatlam:

presentation  →  domain  ←  data
(UI, ScreenModel)  (UseCase, Model, Repository interface)  (API, DB, Repository impl)

SOLID printsiplari

• S - Har bir UseCase 1 vazifa (9 ta alohida UseCase)
• O - Resource<T> sealed class fold/map/flatMap bilan kengaytirilgan
• L - Barcha Repository interface/implementation to'g'ri almashtiriladi
• I - PostRepository va CommentRepository alohida interface
• D - Domain layer hech qanday framework ga bog'liq emas, DI orqali inject

DRY printsiplari

• safeApiCall / safeDbCall - barcha repository'larda yagona error handling
• UiStateScaffold - Scaffold + Loading/Error/Success boilerplate 1 widget
• PostCard - PostList va Favorites da qayta ishlatiladi
• AppTextStyle / AppColor - MaterialTheme wrapper, Flutter dagi context.textTheme kabi

Loyiha tuzilmasi

composeApp/src/commonMain/kotlin/com/example/userfeed/
├── core/
│   ├── constants/         ApiConstants (BASE_URL, timeout)
│   ├── database/          DatabaseDriverFactory (expect/actual)
│   ├── di/                Koin modullar (core, repository, usecase, screenmodel)
│   ├── network/           HttpClientFactory (Ktor + timeout + logging)
│   └── utils/             Resource, UiState, SafeCall, DispatcherProvider
├── data/
│   ├── mapper/            DTO <-> Domain, Entity <-> Domain mapperlar
│   ├── remote/
│   │   ├── dto/           UserDto, PostDto, CommentDto
│   │   └── ApiService     Ktor API chaqiruvlar
│   └── repository/        UserRepositoryImpl, PostRepositoryImpl,
│                          CommentRepositoryImpl, FavoriteRepositoryImpl
├── domain/
│   ├── model/             User, Post, Comment (data class)
│   ├── repository/        UserRepository, PostRepository,
│   │                      CommentRepository, FavoriteRepository (interface)
│   └── usecase/           GetUsersUseCase, RefreshUsersUseCase,
│                          HasUsersUseCase, GetPostsByUserUseCase,
│                          RefreshPostsUseCase, GetPostByIdUseCase,
│                          GetCommentsUseCase, GetFavoritesUseCase,
│                          ToggleFavoriteUseCase
└── presentation/
    ├── components/        AppTopBar, LoadingContent, ErrorContent,
    │                      PostCard, UiStateScaffold
    ├── screens/
    │   ├── splash/        SplashScreen + SplashScreenModel
    │   ├── userlist/      UserListScreen + UserListScreenModel
    │   ├── postlist/      PostListScreen + PostListScreenModel
    │   ├── postdetail/    PostDetailScreen + PostDetailScreenModel
    │   └── favorites/     FavoritesScreen + FavoritesScreenModel
    └── theme/             Color, Type (AppTextStyle, AppColor), Theme

Screenlar

1. Splash Screen

• Ilova ochilganda ko'rsatiladi
• DB da user bor bo'lsa -> User List
• Yo'q bo'lsa API dan yuklaydi
• Xatolik bo'lsa -> Retry tugmasi

2. User List Screen

• API dan userlarni yuklaydi, DB ga saqlaydi
• LazyColumn da user name + email ko'rsatadi
• Pull-to-refresh qo'llab-quvvatlaydi
• User bosilsa -> Post List Screen
• Favorites tugmasi (yulduzcha)

3. Post List Screen

• Tanlangan user postlarini yuklaydi
• DB cache + pull-to-refresh
• Favorite yulduzcha bosilsa -> local DB ga saqlaydi (real-time yangilanadi)
• Post bosilsa -> Post Detail Screen

4. Post Detail Screen

• Post body va commentlar ro'yxati
• Loading / Error state bilan

5. Favorites Screen

• Faqat local DB dan
• Offline ham ishlaydi
• Yulduzcha bosilsa -> favoritdan o'chiradi

Database

SQLDelight bilan 4 ta jadval:

Jadval	Vazifasi
UserEntity	Foydalanuvchilar (id, name, username, email, phone, website)
PostEntity	Postlar (id, userId, title, body)
CommentEntity	Commentlar (id, postId, name, email, body)
FavoritePostEntity	Sevimli postlar (postId, userId, title, body)

Barcha entity'lar offline rejimda ishlaydi - commentlar ham DB da cache qilinadi.

State Management

Har bir screen 3 ta holatni boshqaradi:

sealed interface UiState<out T> {
    data object Loading : UiState<Nothing>
    data class Success<T>(val data: T) : UiState<T>
    data class Error(val message: String) : UiState<Nothing>
}

Error handling Resource<T> sealed class orqali:

sealed class Resource<out T> {
    data class Success<T>(val data: T) : Resource<T>()
    data class Failure(val error: AppError) : Resource<Nothing>()

    fun <R> fold(onSuccess: (T) -> R, onFailure: (AppError) -> R): R
    fun <R> map(transform: (T) -> R): Resource<R>
    fun <R> flatMap(transform: (T) -> Resource<R>): Resource<R>
    fun onSuccess(action: (T) -> Unit): Resource<T>
    fun onFailure(action: (AppError) -> Unit): Resource<T>
    fun getOrNull(): T?
}

AppError

sealed class AppError(open val message: String) {
    data class NetworkError(...)    // IOException - internet yo'q
    data class ServerError(         // 4xx/5xx HTTP xatolik
        override val message: String,
        val code: Int?              // HTTP status code
    )
    data class DatabaseError(...)   // SQLDelight exception
    data class NotFoundError(...)   // Entity topilmadi
    data class UnknownError(...)    // Boshqa exception
}

Cache Strategy: Stale-While-Revalidate

1. Screen ochiladi
2. DB dan eski (stale) data Flow orqali darhol ko'rsatiladi
3. Parallel ravishda API dan yangi data yuklanadi
4. API success -> DB ga yoziladi -> Flow avtomatik yangi data emit qiladi -> UI yangilanadi
5. API fail + DB da data bor -> eski data ko'rinadi (UiState.Success saqlanadi)
6. API fail + DB bo'sh -> UiState.Error ko'rsatiladi

Pull-to-refresh paytida eski data ko'rinishda qoladi, faqat isRefreshing indikator ko'rsatiladi. Xatolik faqat DB ham bo'sh bo'lganda Error state ga o'tadi.

Testing

Test strategiyasi

• Fake Repository pattern - mockk o'rniga manual fake (KMP multiplatform compatible)
• TestDispatcherProvider - Dispatchers.IO o'rniga StandardTestDispatcher inject qilish
• Domain layer frameworksiz - unit test uchun ideal

Test tuzilmasi

commonTest/
├── fake/
│   ├── FakeData.kt              - Test uchun fake User, Post, Comment
│   ├── FakeUserRepository.kt    - UserRepository fake implementatsiyasi
│   ├── FakePostRepository.kt    - PostRepository fake implementatsiyasi
│   ├── FakeCommentRepository.kt - CommentRepository fake implementatsiyasi
│   ├── FakeFavoriteRepository.kt - FavoriteRepository fake implementatsiyasi
│   └── TestDispatcherProvider.kt - DispatcherProvider test implementatsiyasi
├── core/utils/
│   └── ResourceTest.kt          - Resource fold/map/flatMap/onSuccess/onFailure
└── domain/usecase/
    ├── GetUsersUseCaseTest.kt
    ├── RefreshUsersUseCaseTest.kt
    ├── GetPostByIdUseCaseTest.kt
    ├── GetFavoritesUseCaseTest.kt
    └── ToggleFavoriteUseCaseTest.kt

DispatcherProvider - nima uchun kerak?

// Production
class DefaultDispatcherProvider : DispatcherProvider {
    override val io = Dispatchers.IO
}

// Test - barcha coroutine'lar sinxron ishlaydi
class TestDispatcherProvider : DispatcherProvider {
    override val io = StandardTestDispatcher()
}

Bu pattern repository'larni test qilishda withContext(dispatcher.io) ni sinxron qiladi.

Test run qilish

./gradlew :composeApp:allTests

24 ta test (Android + iOS) - barcha UseCase va Resource testlari.

Ishga tushirish

Talablar

• JDK 17
• Android Studio / Fleet
• Xcode (iOS uchun)

Android

./gradlew :composeApp:assembleDebug

iOS

Xcode orqali iosApp/iosApp.xcodeproj ochib run qiling.

Eslatma

JDK 17 kerak. JAVA_HOME environment variable o'rnatilgan bo'lishi shart:

export JAVA_HOME=/path/to/jdk17

user-feed