A modern real-time cryptocurrency price tracker for Android demonstrating Clean Architecture, Coroutines + Flow, and reactive UI.

Features • Architecture • Getting Started

CoinPulse follows Clean Architecture with three clearly separated layers:

Presentation  →  Domain  ←  Data

• Presentation — Jetpack Compose screens, ViewModels exposing StateFlow<UiState>
• Domain — Pure Kotlin use cases and repository interfaces. Zero Android dependencies
• Data — Retrofit + Room implementations, DTOs, mappers, and background workers

CoinGecko API (polling every 30s)
    └── flow { while(true) }
            └── map / combine / catch
                    └── StateFlow in ViewModel
                            └── collectAsStateWithLifecycle in Compose
                                    └── WorkManager (background alerts every 15min)

• flow { while(true) } — manual polling stream from REST API
• StateFlow + stateIn() — converting cold flows to hot, lifecycle-aware state
• combine() — merging market data stream with search query in real time
• catch — error handling in the flow pipeline without crashing the stream
• flowOn(Dispatchers.IO) — moving upstream work off the main thread
• CoroutineWorker — background price alert monitoring via WorkManager
• viewModelScope + SharingStarted.WhileSubscribed(5_000) — lifecycle-aware sharing

• Market — Live crypto prices with 30-second polling and real-time search filtering
• Detail — Individual coin data with price and market cap
• Favorites — Persist favorite coins with Room, reactive UI via Flow<List<Favorite>>
• Alerts — Set price thresholds, monitored in background via WorkManager notifications

com.mauro.coinpulse/
├── core/
│   ├── di/          # Hilt modules (Network, Database, Repository)
│   ├── util/        # NotificationHelper, WorkManagerScheduler
│   └── ui/          # Theme, colors, typography
├── data/
│   ├── local/       # Room entities, DAOs, AppDatabase
│   ├── remote/      # Retrofit API service, DTOs
│   ├── mapper/      # DTO → Domain model converters
│   ├── repository/  # CoinRepositoryImpl
│   └── worker/      # PriceAlertWorker (CoroutineWorker)
├── domain/
│   ├── model/       # Coin, Alert, Favorite
│   ├── repository/  # CoinRepository interface
│   └── usecase/     # GetCoinsUseCase, GetCoinDetailUseCase, etc.
└── presentation/
    ├── market/      # MarketScreen + MarketViewModel
    ├── detail/      # DetailScreen + DetailViewModel
    ├── favorites/   # FavoritesScreen + FavoritesViewModel
    ├── alerts/      # AlertsScreen + AlertsViewModel
    └── navigation/  # NavGraph, Screen sealed class

1. Clone the repository

git clone https://github.com/maurocosentino/coinpulse.git

2. Open in Android Studio Hedgehog or later
3. Run on emulator or physical device (API 26+)
4. No API key required — uses CoinGecko public API

This project was built to go deep on reactive programming in Android. The main takeaways:

• The difference between cold and hot flows and when to use each
• How stateIn() with WhileSubscribed prevents unnecessary upstream work during recomposition
• Why CoroutineWorker is required over Worker when calling suspend functions in background tasks
• How combine() allows merging independent data streams without manual synchronization
• The value of Clean Architecture when the CoinGecko detail endpoint had a different shape than the list endpoint — only the DTO and mapper needed to change, zero impact on domain or UI

Mauro Cosentino Android Developer GitHub