Jetpack Compose State Management for Production Apps

The Production Compose Rule

Compose works best when screens receive stable UI state and send clear user events. The composable should describe what the user sees, while the ViewModel coordinates domain work and state transitions.

data class CheckoutUiState(
    val items: List<CartItem> = emptyList(),
    val isLoading: Boolean = false,
    val error: String? = null
)

State Holders

Use a state holder when local UI behavior becomes meaningful enough to test or reuse. Keep it small, predictable, and close to the screen that owns it.

When To Hoist

Hoist state when another component needs to read or mutate it, when configuration changes matter, or when business rules affect it.

Events Over Callbacks

Typed events make screens easier to evolve.

sealed interface CheckoutEvent {
    data object Retry : CheckoutEvent
    data class QuantityChanged(val id: String, val quantity: Int) : CheckoutEvent
}

Testing Strategy

Test the ViewModel state machine first. Then add targeted Compose tests for accessibility labels, empty states, loading states, and critical actions.