Compose Architecture Review

When to Use This Skill:

• Reviewing EXISTING Compose screens/ViewModels
• Code review for architectural violations
• Refactoring guidance for specific files
• Validating state management patterns

When to Use project-architecture-analyst-android Agent Instead:

• Planning NEW features (uncertain file placement)
• Understanding project-wide architecture
• Major changes affecting multiple modules
• Need to discover existing patterns before implementing

Review Checklist

Separation of Concerns

• Composables: presentation only (no business logic, network, DB)
• ViewModels: state + business logic (StateFlow, events)
• Repository/UseCase: data access separated from UI

State Management

• remember - composable-local state only
• rememberSaveable - survive config changes
• ViewModel with StateFlow/MutableStateFlow - screen state
• collectAsStateWithLifecycle() - lifecycle-aware collection
• derivedStateOf - computed state from other state
• CompositionLocal - shared read-only state
• Use unidirectional data flow: state flows down, events flow up
• Prefer stateless composables (receive value + onChange callbacks)
• Use plain state-holder classes for complex state not tied to lifecycle
• Prefer side effects via LaunchedEffect (async work), DisposableEffect (cleanup), SideEffect (framework integration), produceState, rememberCoroutineScope, or snapshotFlow rather than arbitrary side effects in composable bodies
• Use SavedStateHandle for persistent state across process death

State Lifecycle Issues

• No leaked ViewModels (use viewModel() or hiltViewModel())
• Proper cleanup in ViewModel.onCleared()
• StateFlow collected with lifecycle awareness
• No unnecessary state hoisting

Dependency Injection

• Dependencies injected (check project: Koin, Hilt, Dagger, or manual)
• No hardcoded singletons in composables
• ViewModels receive dependencies via constructor

Composable Design

• Composables are small (single responsibility)
• Complex screens broken into components
• Reusable components extracted
• Stateless composables preferred (state hoisting)

Common Issues

Issue	Fix
Business logic in composable	Extract to ViewModel
Network call in composable	Move to ViewModel with LaunchedEffect
Singleton in composable	Inject via DI or CompositionLocal
200+ line composable	Break into smaller components
State not hoisted	Hoist to parent or ViewModel
Side effects or network calls directly in composable	Wrap in LaunchedEffect(key) { ... } or move to ViewModel
Stateful composable when stateless would suffice	Hoist state and pass value + lambda

State Hoisting Pattern

Composable receives: value: T, onValueChange: (T) -> Unit
ViewModel holds: MutableStateFlow<T>

Severity

• 🔴 Critical: Architecture violation
• 🟡 Improvement: Better pattern available
• 🟢 Enhancement: Optional optimization