android-architecture

MVVM separates UI from business logic across presentation, domain, and data layers. Implement ViewModels to manage UI state, use repositories to abstract data access, and organize code into distinct layers for improved testability and maintainability.

Hilt automates dependency injection by generating boilerplate code and managing scopes. Annotate your Android components with @HiltAndroidApp, use @Inject for field injection, and define dependencies with @Provides or @Binds to create a scalable, test-friendly DI graph.

Clean architecture divides code into presentation, domain, and data layers. The presentation layer holds UI and ViewModels, domain contains business logic and entities, and data implements repositories and external APIs. This structure reduces coupling and improves testing.

Yes, MVVM migration is incremental. Start by introducing ViewModels for new features, extract business logic from Activities, implement the repository pattern gradually, and add Hilt to manage dependencies across features as you refactor.

The repository pattern abstracts data sources and creates a boundary between domain and data layers. It centralizes data logic, makes testing easier by allowing mock implementations, and lets you swap data sources without affecting business logic.