Android — Kotlin

Standar pengembangan aplikasi Android menggunakan Kotlin sebagai bahasa utama.

Tech Stack

Kategori	Library / Tool	Versi Min.
Language	Kotlin	2.4+ (K2 compiler)
Min SDK	API 24 (Android 7.0)	—
Target SDK	API 36 (Android 16)	Wajib untuk app baru per 31 Agu 2026
Build System	Gradle (Kotlin DSL)	9.x
UI	Jetpack Compose	Latest (via Compose BOM)
Navigation	Compose Navigation	Latest
DI	Hilt / Koin	Latest
Networking	Retrofit + OkHttp	3.x + 5.x
Serialization	Kotlinx Serialization	Latest
Image Loading	Coil	3.x (io.coil-kt.coil3, Kotlin Multiplatform)
Local DB	Room	Latest
State Management	ViewModel + StateFlow	—
Testing	JUnit 5, MockK, Turbine	—
CI/CD	Fastlane + GitLab CI	—

Project Structure

app/
├── src/
│   ├── main/
│   │   ├── java/com/bitgroup/appname/
│   │   │   ├── data/              # Data layer
│   │   │   │   ├── remote/        # API services & DTOs
│   │   │   │   ├── local/         # Room DAOs & entities
│   │   │   │   └── repository/    # Repository implementations
│   │   │   ├── domain/            # Domain layer
│   │   │   │   ├── model/         # Domain models
│   │   │   │   ├── repository/    # Repository interfaces
│   │   │   │   └── usecase/       # Use cases
│   │   │   ├── presentation/      # Presentation layer
│   │   │   │   ├── ui/            # Composable screens
│   │   │   │   ├── viewmodel/     # ViewModels
│   │   │   │   └── navigation/    # Nav graph
│   │   │   ├── di/                # Hilt modules
│   │   │   └── core/              # Utilities, extensions
│   │   └── res/
│   └── test/                      # Unit tests
│   └── androidTest/               # Instrumented tests
├── build.gradle.kts
└── gradle/
    └── libs.versions.toml         # Version catalog

Coding Standards

Kotlin Style Guide

• Ikuti Kotlin Coding Conventions resmi.
• Gunakan ktlint atau detekt sebagai linter.
• Maksimum line length: 120 karakter.

Jetpack Compose Best Practices

// ✅ Good - Stateless composable
@Composable
fun UserCard(
    user: UserUiModel,
    onTap: () -> Unit,
    modifier: Modifier = Modifier,
) {
    Card(
        modifier = modifier.clickable(onClick = onTap),
    ) {
        Text(text = user.name)
    }
}

// ❌ Bad - Business logic inside composable
@Composable
fun UserCard(userId: String) {
    val user = repository.getUser(userId) // Jangan!
    Text(text = user.name)
}

ViewModel Pattern

@HiltViewModel
class UserViewModel @Inject constructor(
    private val getUserUseCase: GetUserUseCase,
) : ViewModel() {

    private val _uiState = MutableStateFlow<UserUiState>(UserUiState.Loading)
    val uiState: StateFlow<UserUiState> = _uiState.asStateFlow()

    fun loadUser(id: String) {
        viewModelScope.launch {
            _uiState.value = UserUiState.Loading
            getUserUseCase(id)
                .onSuccess { _uiState.value = UserUiState.Success(it) }
                .onFailure { _uiState.value = UserUiState.Error(it.message) }
        }
    }
}

sealed interface UserUiState {
    data object Loading : UserUiState
    data class Success(val user: User) : UserUiState
    data class Error(val message: String?) : UserUiState
}

Build & Run

# Debug build
./gradlew assembleDebug

# Run unit tests
./gradlew test

# Run lint
./gradlew ktlintCheck

# Generate signed APK
./gradlew assembleRelease

Version Catalog

Semua dependency version harus didefinisikan di gradle/libs.versions.toml untuk konsistensi multi-module project.