State
Holds a piece of UI/domain state and exposes it read-only, implementing the FLOW_010 backing property pattern: the MutableStateFlow is private, so external code can only change state through set and update.
Example:
class CounterViewModel {
private val holder = StateHolder(0)
val count: StateFlow<Int> = holder.state
fun increment() = holder.update { it + 1 }
}It is a final class (not open): extending it could not add safety, and a final type keeps the guarantee that the mutable flow is never exposed by a subclass.
Rules: FLOW_010 (never expose MutableStateFlow/MutableSharedFlow publicly). See docs/BEST_PRACTICES_COROUTINES.md section 9.5.
Thread-safe: reads, set and update may be used from any thread.
Requires opting in to ExperimentalStructuredCoroutines.
Parameters
the initial state.
Type Parameters
the state type.
See also
Properties
Functions
Replaces the value. Prefer update when the new value depends on the current one. Like MutableStateFlow, equal values are conflated and not re-emitted.