kotlin--androidlisted

# Kotlin + Android ## When to activate - Building Android apps with Jetpack Compose - Setting up ViewModel with StateFlow or SharedFlow - Configuring Room database (entity, DAO, database class) - Integrating Retrofit for HTTP and Moshi/Gson for JSON - Wiring dependency injection with Hilt - Preparing a release for Google Play Store submission ## When NOT to use - Cross-platform Flutter or React Native projects - Android apps still using Views/XML layouts with no Compose involvement - Kotlin Multiplatform (KMP) projects where Android is just one target ## Instructions ### Compose Recomposition Optimization Recomposition reruns composable functions when their inputs change. Avoid unnecessary work: **Use `remember` to cache computed values and objects across recompositions:** ```kotlin @Composable fun ExpensiveList(items: List<Item>) { // Without remember — sorted on every recomposition val sorted = items.sortedBy { it.name } // With remember — re-sorts only when items reference changes val sorted = remember(items) { items.sortedBy { it.name } } LazyColumn { items(sorted, key = { it.id }) { item -> ItemRow(item) } } } ``` **Use `derivedStateOf` for values derived from observable state to reduce recomposition frequency:** ```kotlin @Composable fun ScrollToTopButton(listState: LazyListState) { // Without derivedStateOf — recomposes on every scroll pixel val showButton = listState.firstVisibleItemIndex > 0