Real-time stock price tracking for Android
Live prices · Animated charts · Price alerts · Order book · Watchlist · Offline support
Most Android portfolio projects stop at a basic list that fetches data once. PricePulse goes further by solving the problems that come up in real trading apps:
| Real-world problem | How PricePulse handles it |
|---|---|
| Live data at sub-second latency | Finnhub WebSocket with 30 s ping keepalive |
| Network drops killing the feed | Exponential back-off reconnect (1 s → 64 s + jitter) |
| Cold-start with no data yet | REST snapshot on launch — list is never blank |
| User goes offline mid-session | Cached prices shown with "X min ago" banner |
| Alerts when app is closed | WorkManager AlertCheckWorker runs every 15 min |
| Charts that feel alive | Cubic Bézier path + 600 ms animated clip per update |
The goal was not just to make a demo — it was to build something that handles the same edge cases a production trading app would need to handle.
- WebSocket feed via Finnhub for 25 NASDAQ stocks simultaneously
- REST snapshot on every launch so the list is populated before the socket connects
- Price flash animation — each row briefly glows green (up) or red (down) on every tick
- Animated line chart — cubic Bézier curves, vertical gradient fill, 600 ms left-to-right entry
- Latest-price dot with glow ring pinned to the chart's current endpoint
- Order book panel — bids (green) vs. asks (red) with proportional depth bars and spread display
- Price alerts — set ABOVE or BELOW a target price; system notification fires when triggered
- Background polling — WorkManager job checks alerts every 15 minutes, even when the app is closed
- Watchlist — star any symbol; persisted across sessions with DataStore
- Offline cache — SharedPreferences-backed snapshot; shows "cached · N min ago" banner
- Dark / Light mode toggle — Binance-inspired dark palette by default
- Android 12 SplashScreen API — adaptive icon on dark canvas with 400 ms fade-out
- Edge-to-edge layout, Material 3, and dynamic typography
Clean Architecture with three strictly separated layers and MVVM in the presentation tier. Hilt wires the dependency graph at compile time.
┌─────────────────────────────────────────────────────────────────────┐
│ PRESENTATION LAYER │
│ │
│ ┌──────────────────────────┐ ┌─────────────────────────────┐ │
│ │ Jetpack Compose UI │◀─────│ PriceTrackerViewModel │ │
│ │ │ │ │ │
│ │ PriceTrackerScreen │ │ StateFlow<PriceTrackerUI │ │
│ │ ├─ TradingTopBar │ │ State> │ │
│ │ ├─ TradingTabRow │ │ ├─ stocks: List<Stock> │ │
│ │ │ MARKETS / WATCHLIST│ │ ├─ watchlist: Set<String> │ │
│ │ ├─ PriceList │ │ ├─ alerts: List<Alert> │ │
│ │ ├─ StockChartPanel │ │ ├─ isConnected: Boolean │ │
│ │ │ └─ PriceLineChart │ │ ├─ isOffline: Boolean │ │
│ │ ├─ OrderBookPanel │ │ └─ orderBook: OrderBook? │ │
│ │ └─ SetAlertDialog │ └─────────────────────────────┘ │
│ └──────────────────────────┘ │
└──────────────────────────────────────────┬──────────────────────────┘
│ 13 use cases
┌──────────────────────────────────────────▼──────────────────────────┐
│ DOMAIN LAYER │
│ (zero Android imports) │
│ │
│ Use Cases Entities │
│ ├─ GetInitialStocksUseCase ├─ Stock │
│ ├─ GetCachedStocksUseCase ├─ PriceAlert (ABOVE/BELOW) │
│ ├─ SubscribeToPriceUpdatesUseCase ├─ OrderBook │
│ ├─ WatchSymbolsUseCase └─ OrderBookEntry │
│ ├─ ManageConnectionUseCase │
│ ├─ ObserveWatchlistUseCase Repository interfaces │
│ ├─ AddToWatchlistUseCase ├─ PriceRepository │
│ ├─ RemoveFromWatchlistUseCase ├─ WatchlistRepository │
│ ├─ ObserveAlertsUseCase ├─ AlertRepository │
│ ├─ AddAlertUseCase └─ ConnectionRepository │
│ ├─ RemoveAlertUseCase │
│ ├─ CheckAlertsUseCase │
│ └─ ObserveOrderBookUseCase │
└──────────────────────────────────────────┬──────────────────────────┘
│ concrete implementations
┌──────────────────────────────────────────▼──────────────────────────┐
│ DATA LAYER │
│ │
│ ┌─────────────────────┐ ┌───────────────────┐ ┌─────────────────┐ │
│ │ WebSocket │ │ REST (Finnhub) │ │ Local storage │ │
│ │ │ │ │ │ │ │
│ │ wss://ws.finnhub.io │ │ /api/v1/quote │ │ DataStore │ │
│ │ │ │ 25 symbols/launch │ │ watchlist + │ │
│ │ Exponential back-off│ │ OkHttp + Gson │ │ alerts │ │
│ │ 1 s → 64 s + jitter │ │ │ │ │ │
│ │ 30 s ping keepalive │ │ │ │ SharedPrefs │ │
│ └─────────────────────┘ └───────────────────┘ │ price cache │ │
│ └─────────────────┘ │
└─────────────────────────────────────────────────────────────────────┘
▲ Hilt DI wires all dependencies
Finnhub WebSocket
│ tick JSON
▼
WebSocketDataSource (SharedFlow, capacity 64)
│
▼
SubscribeToPriceUpdatesUseCase
│
▼
PriceTrackerViewModel
├─ updates priceHistory (ArrayDeque, max 50 points)
├─ computes flash colour (BullGreen / BearRed)
└─ emits new StateFlow snapshot
│
▼
Compose recomposes affected rows only
Multi-module Gradle architecture for scalability, maintainability, and clean separation of concerns.
| Module | Responsibility |
|---|---|
:app |
Entry point and navigation |
:core:network |
WebSocket + networking setup |
:core:common |
Shared utilities |
:domain |
Business logic, use cases, and repository interfaces |
:data |
Repository implementations and data sources |
:feature:price |
UI screens and ViewModel |
- Independent feature development — each module compiles and tests in isolation
- Faster builds — Gradle only recompiles changed modules
- Better testability — minimal surface area per module
| Layer | Library / Tool | Version |
|---|---|---|
| Language | Kotlin | 2.3 |
| UI | Jetpack Compose + Material 3 | BOM 2025 |
| DI | Hilt | 2.59 |
| Async | Coroutines · StateFlow · SharedFlow | 1.10 |
| Network | OkHttp (WebSocket + REST) | 5.3 |
| Serialisation | Gson | 2.13 |
| Local storage | DataStore Preferences | 1.2 |
| Background work | WorkManager | 2.10 |
| Splash screen | AndroidX Core SplashScreen | 1.0 |
| Build | Gradle KTS + Version Catalog | AGP 9.1 |
Runs on every push and pull request to main via GitHub Actions.
- Build —
./gradlew assembleDebug - Unit tests —
./gradlew testacross all modules - Lint —
./gradlew lint - APK artifact — debug APK uploaded as a workflow artifact
- Android Studio Meerkat 2024.3 or later
- JDK 17
- A free Finnhub API key (no credit card required)
git clone https://github.com/mohd-aquib/Realtime-Price-Tracker.git
cd Realtime-Price-TrackerEdit app/src/main/java/com/aquib/pricepulse/data/config/Constants.kt:
const val API_KEY = "your_finnhub_api_key_here"./gradlew installDebugOr press Run ▶ in Android Studio. The free Finnhub plan covers all 25 default symbols.
com.aquib.pricepulse/
│
├── MainActivity.kt
├── PricePulseApp.kt
│
├── di/
│ └── DataModule.kt # Hilt @Provides and @Binds
│
├── domain/ # No Android dependencies
│ ├── config/Constants.kt # 25 default stock symbols
│ ├── entities/
│ │ ├── Stock.kt
│ │ ├── PriceAlert.kt # AlertCondition: ABOVE | BELOW
│ │ ├── OrderBook.kt
│ │ └── OrderBookEntry.kt
│ ├── repositories/ # Interfaces only
│ └── usecases/ # 13 single-responsibility classes
│
├── data/
│ ├── config/Constants.kt # API_KEY, WS_URL, endpoints
│ ├── datasource/
│ │ ├── WebSocketDataSource.kt # OkHttp WS + back-off + reconnect
│ │ └── FinnhubRestDataSource.kt # Quote endpoint, coroutine IO
│ ├── local/
│ │ ├── StockCacheDataSource.kt # SharedPrefs snapshot + timestamp
│ │ ├── WatchlistDataSource.kt # DataStore persistence
│ │ └── AlertDataSource.kt # DataStore persistence
│ ├── dto/
│ │ ├── FinnhubDtos.kt
│ │ └── PriceUpdateDto.kt
│ ├── repositories/ # 4 concrete implementations
│ ├── worker/AlertCheckWorker.kt # WorkManager 15-min alert poll
│ └── notification/NotificationHelper.kt
│
└── presentation/
├── state/PriceTrackerUiState.kt
├── viewmodel/PriceTrackerViewModel.kt
└── ui/
├── PriceTrackerScreen.kt # Markets + Watchlist tabs
├── PriceLineChart.kt # Cubic Bézier + animated clip
├── OrderBookPanel.kt # Depth bars, spread display
├── SetAlertDialog.kt
└── theme/
├── Color.kt # Binance-inspired dark palette
├── Theme.kt
└── Type.kt
25 NASDAQ tech stocks configured out of the box:
AAPL GOOG TSLA AMZN MSFT NVDA META NFLX ADBE CRM
INTC AMD ORCL CSCO IBM QCOM AVGO TXN MU AMAT
LRCX KLAC NOW SNPS CDNS
To add or swap symbols, edit domain/config/Constants.kt:
val STOCK_SYMBOLS = listOf("AAPL", "GOOG", /* your symbols */)Distributed under the MIT License. See LICENSE for details.
- Fork the repository
- Create a branch:
git checkout -b feature/my-feature - Commit:
git commit -m 'Add my feature' - Push:
git push origin feature/my-feature - Open a Pull Request
Built by Mohd Aquib · Data by Finnhub