ProvidableCompositionLocal

Class

Common

public abstract class ProvidableCompositionLocal<T> internal constructor(defaultFactory: () -> T) :
    CompositionLocal<T>(defaultFactory)

A ProvidableCompositionLocal can be used in CompositionLocalProvider to provide values.

Functions

public infix fun provides(value: T): ProvidedValue<T>

Associates a CompositionLocal key to a value in a call to CompositionLocalProvider.

public infix fun providesDefault(value: T): ProvidedValue<T>

Associates a CompositionLocal key to a value in a call to CompositionLocalProvider if the key does not already have an associated value.

public infix fun providesComputed(
        compute: CompositionLocalAccessorScope.() -> T
    ): ProvidedValue<T>

Associates a CompositionLocal key to a lambda, compute, in a call to CompositionLocal. The compute lambda is invoked whenever the key is retrieved. The lambda is executed in the context of a CompositionLocalContext which allow retrieving the current values of other composition locals by calling CompositionLocalAccessorScope.currentValue, which is an extension function provided by the context for a CompositionLocal key.

The lambda passed to providesComputed will be invoked every time the CompositionLocal.current is evaluated for the composition local and computes its value based on the current value of the locals referenced in the lambda at the time CompositionLocal.current is evaluated. This allows providing values that can be derived from other locals. For example, if accent colors can be calculated from a single base color, the accent colors can be provided as computed composition locals. Providing a new base color would automatically update all the accent colors.