Currency Buddy V2

Currency Buddy V2 is an enhanced multi-module currency converter app for Android, built with Jetpack Compose and following modern best practices. The project has been re-architected for improved modularity, maintainability, and performance. Whether you’re looking for a quick conversion or interested in exploring the modular design, Currency Buddy V2 has you covered.

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Table of Contents

• Tech Stack & Tools Used
• Features
• Architecture & Modularization
• Widget Integration
• Getting Started
• Contributing
• Support
• License

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Tech Stack & Tools Used

• Kotlin — Modern Android-first language
• Jetpack Compose — Declarative UI toolkit
• Room Database — Local persistence
• WorkManager — Background task scheduling
• Ktor Client — Asynchronous networking
• Koin — Dependency injection framework
• Coroutines + Flow — Reactive streams and concurrency
• DataStore — Preferences and proto data storage
• Glance API — Jetpack-based App Widgets
• Timber — Structured logging
• JUnit5 & MockK — Testing framework
• Firebase (Crashlytics & Analytics) — Error monitoring and analytics

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Features

• 🔄 Real-time and cached currency conversion
• 🧱 Fully modular architecture
• ✨ App Widget integration with Jetpack Glance
• 📴 Offline-first currency support
• ✅ Extensible widget update services

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Architecture & Modularization

Currency Buddy V2 is structured around layered and feature-based modularization:

🧩 Modules

• :core:data — Network & local data logic
• :core:domain — Business logic, interfaces, and use cases
• :core:local — Room + DataStore implementations
• :core:remote — Ktor API layer
• :core:presentation:designsystem — Shared design components
• :core:presentation:ui — Common UI helpers
• :converter:data, :converter:domain, :converter:presentation — Feature-specific logic
• :auth: — Onboarding and authentication (coming soon)
• :widget:presentation — Glance-powered widget integration

🔄 App Widget (Glance)

• Uses GlanceAppWidget and GlanceAppWidgetReceiver
• Updates in real-time using flows and repository pattern
• Integrates with WorkManager for background updates
• Separates widget logic via:
  • ConverterWidgetUpdater — focused updater interface
  • WidgetUpdater — generic interface for multiple widgets
  • DefaultConverterWidgetUpdater — image download, URI creation, widget binding
• Handles SVG image rendering using Coil + FileProvider
• Shown placeholder using android:initialLayout

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Widget Integration

Widgets follow clean principles:

• Interface Segregation: Small, dedicated interfaces for each widget
• Dependency Injection: Updaters are injected via Koin
• Composable Architecture: Widget state updates via DataStore & updateAppWidgetState
• Boot Resilience: WorkManager continues syncing even after device reboots
• Glance Placeholder: android:initialLayout includes helpful text + app logo
• Optimized Image Caching: Images are downloaded and served via FileProvider and Coil

Widget Sync Flow:

WorkManager/Repository emits -> ViewModel or Worker collects -> WidgetUpdater updates state -> Widget renders

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Getting Started

Prerequisites

• Android Studio (latest)
• API key and endpoints defined in your .env or local.properties file:
  • API_KEY
  • CONVERTER_BASE_URL
  • CURRENCY_DETAILS_URL

Installation

git clone https://github.com/ericwafula/currencybuddyV2.git
cd currencybuddyV2

Open in Android Studio and run on a device or emulator.

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Contributing

We welcome contributions to Currency Buddy! Feel free to open issues, fork the repo, and submit PRs. See CONTRIBUTING.md for more details.

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Support

If you find this project useful, consider starring ⭐ it or buying me a coffee ☕.

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License

This project is licensed under the MIT License.