android-coroutines

Use Kotlin Coroutines in an Android ViewModel by launching jobs within viewModelScope and injecting dispatchers via the constructor to ensure main safety and structured concurrency. Expose repository fetched data as StateFlow to reliably manage UI state without leaking contexts.

The best way to collect Flow in Android without lifecycle crashes is using repeatOnLifecycle alongside lifecycleScope. This pattern ensures Flow collection only happens when the lifecycle is at least started, automatically suspending and resuming collection to prevent background emission leaks.

Test suspend functions and Flow in Android unit tests by injecting TestDispatcher instances into your ViewModels and wrapping test bodies with runTest. This approach controls virtual time and dispatcher execution, allowing you to verify Flow emissions, cancellation semantics, and error handling deterministically.

Use StateFlow for Android UI state when you need a single updated value holder that always has a latest state, and use SharedFlow for event-based scenarios like navigation or snackbar messages. Both integrate with viewModelScope to ensure structured concurrency and proper lifecycle handling.

Kotlin Coroutines leak memory when the Android screen closes if launched outside viewModelScope or lifecycleScope without structured concurrency. Enforce parent-child job hierarchies and use injected dispatchers to ensure active coroutines are properly cancelled upon lifecycle destruction.