android-data-layer

An offline-first Android data layer uses the Repository pattern to coordinate local Room caching with Retrofit network fetches, establishing a single source of truth (SSOT) for deterministic data access. It leverages read-through caching with stale-while-revalidate strategies to ensure smooth UX under intermittent connectivity.

To synchronize Room cache with Retrofit fetches, use Flow-based DAOs for local data emission and suspend API calls for network requests. The Repository orchestrates this by triggering remote fetches and updating the Room database, which acts as the SSOT that the UI observes.

The best way to handle intermittent connectivity is using an offline-first architecture with read-through caching and stale-while-revalidate. For background synchronization, an optional outbox pattern with WorkManager can queue network operations until connectivity is restored.

Yes, this Android data layer architecture requires Hilt dependency injection to bind repository interfaces to their concrete implementations. Hilt manages the lifecycle and injection of Room database instances and Retrofit API interfaces throughout the app components.

Yes, WorkManager supports an optional outbox pattern for background synchronization in offline-first Android apps. It handles deferred network tasks and ensures data consistency when the device regains connectivity, complementing the primary read-through caching mechanism.

An offline-first repository intentionally returns stale data from the Room cache when offline to maintain UX. It uses stale-while-revalidate to serve cached data immediately while attempting a background Retrofit fetch to update the SSOT once connectivity returns.