Migrating from LiveData to StateFlow Without UI Regressions

Migrating from LiveData to StateFlow Without UI Regressions

Teams switch to StateFlow for consistency, then accidentally break one-shot events and loading states. The migration works when you separate state streams from event streams clearly.

Step 1: map existing screen state into immutable data class

data class ScreenState(
    val loading: Boolean = false,
    val items: List<String> = emptyList(),
    val error: String? = null
)

Step 2: expose persistent state via StateFlow

private val _state = MutableStateFlow(ScreenState())
val state: StateFlow<ScreenState> = _state

Step 3: keep one-time actions on SharedFlow

private val _events = MutableSharedFlow<UiEvent>()
val events = _events.asSharedFlow()

Pitfall

Using StateFlow for toast/navigation events. Those replay after rotation and create duplicate actions.

Verification

• Rotation preserves state without duplicate events.
• Event handling remains one-shot.
• UI tests pass across configuration changes.