android-architecture

To structure an Android app using clean architecture and Hilt, separate your project into UI, Domain, and Data layers with strict inward dependencies, then wire them together using Hilt annotations like @HiltAndroidApp and @HiltViewModel to promote testability and clean wiring.

The best way to modularize an Android project involves creating distinct core modules like :core:model, :core:data, :core:domain, and :core:ui, alongside an :app module and specific feature modules, which improves build times and enforces strict separation of concerns across the codebase.

You need a domain layer in your Android app architecture when you want to enforce separation of concerns and maintain strict inward dependencies, isolating business logic from the UI and Data layers to ensure scalable and maintainable code across simple to complex applications.

Hilt dependency injection works seamlessly with multi-module Android apps by utilizing module bindings and entry points like @AndroidEntryPoint, allowing you to cleanly wire UI components and ViewModels across feature and core modules while maintaining strict architectural boundaries.

To migrate existing Android code to clean architecture, first establish core modules like :core:model and :core:domain, then gradually move your code into the new structure while verifying dependency directions, ensuring that UI and Data layers strictly depend on Domain and never the reverse.