api/dev.s7a.strata.component/CycleButtonState

CycleButtonState

class CycleButtonState<T : Any>(values: List<T>, initialValue: T)(source)

Caller-owned selected value and display conversion for one generic CycleButton.

The read-only nonempty option snapshot defines forward and backward wraparound order. Every value must be unique by equality, and writes outside the option set fail without mutation. The primary list constructor uses Any.toString, while the collection constructor and enum factory retain their supplied conversion for the state lifetime. Selection, observation, and display conversion are confined to the execution owner that creates the state. The display conversion runs synchronously when called directly or when a CycleButton snapshots its labels, is not used for option identity, and propagates its exceptions unchanged.

Parameters

values

nonempty unique option order.

initialValue

initially selected member of CycleButtonState.values.

Type Parameters

T

immutable option type.

Throws

IllegalArgumentException

when CycleButtonState.values is empty or contains equal members, or when initialValue is outside CycleButtonState.values.

Constructors

CycleButtonState

constructor(values: List<T>, initialValue: T)

constructor(values: Collection<T>, initialValue: T, toString: (T) -> String)

Creates state from one caller-owned collection snapshot and explicit display conversion.

constructor(values: List<T>)

Creates state selecting the first member of a validated nonempty CycleButtonState.values list.

Types

object Companion

Type-specific state factories.

Properties

var value: T

Current selected option.

val values: List<T>

Functions

fun format(value: T): String

Formats one option through the conversion supplied at construction.

fun next(): T

Selects and returns the next option with wraparound.

fun observe(callback: (T) -> Unit): ComponentStateSubscription

Installs one privileged retained observer.

fun previous(): T

Selects and returns the previous option with wraparound.