Opinionated conventions for building modern Android apps with Jetpack Compose and Kotlin.
# Jetpack Compose Android App taste of an Android engineer - Build new screens entirely in Jetpack Compose and keep Views only behind interop for legacy parts. Confidence: 0.90 - Write the whole app in Kotlin with coroutines and Flow; no new RxJava or Java code. Confidence: 0.90 - Follow unidirectional data flow: the ViewModel exposes one immutable UiState as StateFlow and receives events. Confidence: 0.90 - Collect flows in composables with collectAsStateWithLifecycle, not plain collectAsState. Confidence: 0.85 - Hoist state out of composables so most UI functions are stateless and previewable. Confidence: 0.90 - Pass a Modifier parameter as the first optional argument of every reusable composable. Confidence: 0.85 - Keep side effects in LaunchedEffect, DisposableEffect or the ViewModel, never directly in the composable body. Confidence: 0.90 - Mark UI models immutable and use stable collections so recomposition stays cheap. Confidence: 0.75 - Use Hilt for dependency injection and avoid service locators or global singletons. Confidence: 0.80 - Use the repository pattern with Room for local data and Retrofit or Ktor for the network, offline first where it matters. Confidence: 0.80 - Use type-safe Navigation Compose routes instead of string-built destinations. Confidence: 0.80 - Modularize by feature with a shared core module once the app grows past a handful of screens. Confidence: 0.70 - Manage dependencies with a Gradle version catalog and convention plugins instead of copy-pasted build files. Confidence: 0.85 - Use Material 3 with a custom theme and dynamic color, and never hardcode colors or text sizes in screens. Confidence: 0.85 - Write @Preview functions for every screen state: loading, empty, error, content, dark mode and large font. Confidence: 0.80 - Test ViewModels with Turbine and kotlinx-coroutines-test, and UI with the Compose testing APIs. Confidence: 0.85 - Add contentDescription or semantics to every meaningful image and icon button for TalkBack. Confidence: 0.90 - Use WorkManager for deferrable background work and never keep long tasks alive in a ViewModel. Confidence: 0.85 - Enable R8 with tested keep rules and ship Baseline Profiles for faster startup. Confidence: 0.80 - Run ktlint or detekt and Android Lint in CI and treat new warnings as errors. Confidence: 0.75 - Keep strings in resources from day one so localization never requires a refactor. Confidence: 0.85
