---

name: android-concurrency description: Write correct coroutine scopes, lifecycle collection, and dispatcher injection in Android production code. Use for suspend functions, coroutine scopes, and dispatcher mechanics; defer ViewModel StateFlow/LiveData architecture, Fragment lifecycle recipes, persistence/notifications, and unit-test recipes to their specific skills. metadata: triggers: files: - '/*ViewModel.kt' - '/*UseCase.kt' - '**/*Repository.kt' keywords: - suspend - viewModelScope - lifecycleScope - Flow - coroutine - Dispatcher - DispatcherProvider - GlobalScope

Android Concurrency Standards

Priority: P0 (CRITICAL)

Implementation Guidelines

Structured Concurrency

• Scopes: Always use viewModelScope (VM) or lifecycleScope (Activity/Fragment).
• Dispatchers: INJECT Dispatchers (DispatcherProvider) for testability. not hardcode Dispatchers.IO.

Flow usage

• Cold Streams: Use Flow for data streams.
• Hot Streams: Use StateFlow (State) or SharedFlow (Events).
• Replay: Use SharedFlow with replay only when late subscribers must receive recent events.
• Collection: Use collectAsStateWithLifecycle() (Compose) or repeatOnLifecycle (Views).

Anti-Patterns

• No GlobalScope: Use viewModelScope or lifecycleScope — never GlobalScope.
• No async/await by default: Prefer simple suspend functions; async only for parallel calls.

References

• Dispatcher Pattern

Canonical response anchors

• Additional task-grounded exact anchors: hardcode