A modern multi-module Android Weather App built entirely with Kotlin and Jetpack Compose, following Clean Architecture, MVVM, and SOLID principles.
The app uses OpenWeatherMap One Call API 3.0 as its primary data source and integrates Google Maps API for city search and location detection.

• Practice Jetpack Compose UI
• Learn and apply Koin for dependency injection
• Implement Clean Architecture + MVVM
• Implement modularization in Android projects
• Use Kotlin Coroutines and Flow for asynchronous programming
• Use Retrofit with Kotlinx Serialization for networking
• Implement location services with FusedLocationProvider
• Implement Navigation with Navigation3
• Integrate OpenWeather and Google Maps APIs

The project follows Clean Architecture and modularization best practices.

Weather/
├── app/                     # Entry point: WeatherApp, MainActivity, DI initialization, navigation
├── build-logic/             # Gradle build logic (convention plugins)
├── core/
│   ├── ui/                  # Compose theme, Material 3, shared UI components
│   ├── utils/               # General utilities, extensions
│   ├── location/            # FusedLocationProvider logic
│   └── test-utils/          # Testing utilities
├── feature/
│   ├── forecast/            # Main screen: current weather + forecast
│   ├── search/              # City and map search screen
│   └── settings/            # Settings, theme control, favorites
└── build.gradle(.kts)

Inside each feature module:

feature/weather/
├── data/        # DTOs, repository implementations, mappers
├── domain/      # Models, use cases, repository interfaces
├── presentation/# ViewModels, state holders, Compose UI
└── di/          # Koin module definitions

Dependency direction:

app → feature:* → core:* → external libraries

API keys are stored in a non-tracked apikeys.properties file:

OPEN_WEATHER_API_KEY=your_api_key_here
GOOGLE_MAPS_API_KEY=your_google_maps_key_here

• Shows current weather based on device location
• Displays hourly forecast (up to 8 hours)
• Displays daily forecast (up to 8 days)
• Supports switching between favorite cities

• Search city by name
• Search by map (Google Maps)
• “Find Me” button to detect current position

• Switch theme (Light / Dark / System)
• Change default city
• “About” section

Clean project:

./gradlew clean

Assemble debug build:

./gradlew assembleDebug

Assemble release build:

./gradlew assembleRelease

Refresh dependencies and rebuild:

./gradlew clean build --refresh-dependencies

Documentation

Example request:

https://api.openweathermap.org/data/3.0/onecall?lat={lat}&lon={lon}&appid={API_KEY}&units=metric

• Add Room for caching favorite cities
• Add notifications for weather alerts
• Add detailed 8-day forecast screen
• Add Gradle scripts for automatic module creation
• Add TOML and Gradle auto-formatting tasks

Andrey Merkulov
Android Developer • Kotlin