Android Coroutines Expert Skill

Workflow

1. Identify scope — Determine the correct CoroutineScope (viewModelScope, lifecycleScope, or injected applicationScope).
2. Wire data layer — Expose data as suspend functions (one-shot) or Flow (streams) with injected Dispatchers.
3. Connect UI — Collect flows using repeatOnLifecycle(Lifecycle.State.STARTED) and expose read-only StateFlow.
4. Verify — Run ./gradlew test and confirm coroutine behavior. If tests fail, check: uncaught CancellationException in generic catch blocks, GlobalScope usage causing leaked coroutines, missing awaitClose in callbackFlow, or hardcoded Dispatchers breaking test determinism. Run ./gradlew detektDebug to catch structural issues.

Critical Rules

1. Dispatcher Injection (Testability)

• NEVER hardcode Dispatchers (e.g., Dispatchers.IO, Dispatchers.Default) inside classes.
• ALWAYS inject a CoroutineDispatcher via the constructor.
• DEFAULT to Dispatchers.IO in the constructor argument for convenience, but allow it to be overridden.