Unit testing verifies individual components in isolation. I use JUnit 5 or JUnit 4 as the test framework with @Test annotations. MockK provides Kotlin-friendly mocking—mockk<T>() creates mocks, every { } stubs behavior, verify { } confirms calls

EncryptedSharedPreferences secures simple key-value data using Android Keystore. I create instances with EncryptedSharedPreferences.create() specifying encryption schemes. The master key uses MasterKeys or MasterKey.Builder for automatic key generatio

Paging 3 loads large datasets incrementally with network and database support. I create a PagingSource implementing load() method to fetch pages. RemoteMediator orchestrates network and database, fetching from API and caching locally. Pager configurat

Material Design 3 (Material You) brings dynamic theming to Android. I define color schemes with primary, secondary, tertiary colors and their variants. MaterialTheme composable wraps the app with colorScheme, typography, and shapes. Dynamic colors use

WorkManager schedules deferrable, guaranteed background work. I create Worker or CoroutineWorker subclasses with doWork() method. Constraints specify when work runs—network type, charging status, battery level. One-time requests use OneTimeWorkRequest

RecyclerView displays large datasets efficiently with view recycling. I create a ViewHolder to cache view references and an Adapter to bind data. DiffUtil calculates minimal updates using areItemsTheSame and areContentsTheSame callbacks, improving per

Navigation Component provides consistent navigation with type-safe argument passing. I define navigation graph in XML with destinations and actions. NavController handles navigation with navigate() and popBackStack(). Safe Args plugin generates type-s

Hilt simplifies dependency injection in Android with compile-time code generation. I annotate Application class with @HiltAndroidApp and activities/fragments with @AndroidEntryPoint. Modules marked with @Module and @InstallIn define how to provide dep

Retrofit simplifies HTTP networking with type-safe API definitions. I define service interfaces with annotated methods—@GET, @POST, @PUT, @DELETE. Path parameters use @Path, query params use @Query, and request bodies use @Body. Retrofit converts resp

Room provides an abstraction layer over SQLite for compile-time verified database access. I define entities with @Entity annotation, specifying table structure and relationships. DAOs (Data Access Objects) marked with @Dao contain query methods using

MVVM separates concerns in Android apps—Model holds data, View displays UI, ViewModel mediates with business logic. ViewModels survive configuration changes, preventing data loss during rotation. I use ViewModel class with viewModelScope for coroutine

Kotlin coroutines provide structured concurrency for asynchronous programming. I use suspend functions to mark async code, and launch or async to start coroutines. viewModelScope and lifecycleScope tie coroutines to component lifecycles, cancelling au