android-jetpack-compose

Use remember with mutableStateOf to keep state across recompositions, and rememberSaveable when the state must survive configuration changes like rotation. For computed values, use derivedStateOf so expensive calculations only rerun when dependencies change.

Expose a StateFlow from the ViewModel and collect it in the composable with collectAsStateWithLifecycle. Pass state down and events up by calling ViewModel methods from callbacks, keeping composables stateless and testable.

State hoisting moves state out of a composable into its caller, making the composable stateless and reusable. The child receives the value and an onChange callback, while the parent owns the actual state.

Frequent recomposition usually comes from reading state in the wrong scope, missing stable keys in lazy lists, or running heavy computation directly during composition. Wrap expensive work in remember with derivedStateOf and provide stable keys to LazyColumn items.

Use LaunchedEffect for suspend work tied to a key, such as loading data when an ID changes. Use DisposableEffect when you must register and clean up resources like lifecycle observers, with cleanup in onDispose.

Yes, MaterialTheme accepts a colorScheme built from lightColorScheme and darkColorScheme, plus typography. Composables then read colors and text styles from MaterialTheme.colorScheme and MaterialTheme.typography.