Composition
Known direct subclasses
ControlledComposition

A controlled composition is a Composition that can be directly controlled by the caller.
ReusableComposition

A ReusableComposition is a Composition that can be reused for different composable content.
Known indirect subclasses
PausableComposition

A PausableComposition is a sub-composition that can be composed incrementally as it supports being paused and resumed.

A composition object is usually constructed for you, and returned from an API that is used to initially compose a UI. For instance, setContent returns a Composition.

The dispose method should be used when you would like to dispose of the UI and the Composition.

Summary

Public functions
Unit

Clear the hierarchy that was created from the composition and release resources allocated for composition.
Cmn
Unit
setContent(content: @Composable () -> Unit)

Update the composition with the content described by the content composable.
Cmn

Public properties
Boolean

Returns true if any pending invalidations have been scheduled.
Cmn
Boolean

True if dispose has been called.
Cmn

Extension functions
CompositionObserverHandle?

Observe the composition.
Cmn

Public functions

dispose

Cmn
Added in 1.0.0
fun dispose(): Unit

Clear the hierarchy that was created from the composition and release resources allocated for composition. After calling dispose the composition will no longer be recomposed and calling setContent will throw an IllegalStateException. Calling dispose is idempotent, all calls after the first are a no-op.

setContent

Cmn
Added in 1.0.0
fun setContent(content: @Composable () -> Unit): Unit

Update the composition with the content described by the content composable. After this has been called the changes to produce the initial composition has been calculated and applied to the composition.

Will throw an IllegalStateException if the composition has been disposed.

Parameters
content: @Composable () -> Unit

A composable function that describes the content of the composition.
Throws
kotlin.IllegalStateException

thrown in the composition has been disposed.

Public properties

hasInvalidations

Cmn
Added in 1.0.0
val hasInvalidations: Boolean

Returns true if any pending invalidations have been scheduled. An invalidation is schedule if RecomposeScope.invalidate has been called on any composition scopes create for the composition.

Modifying MutableState.value of a value produced by mutableStateOf will automatically call RecomposeScope.invalidate for any scope that read State.value of the mutable state instance during composition.

See also
RecomposeScope
mutableStateOf

isDisposed

Cmn
Added in 1.0.0
val isDisposed: Boolean

True if dispose has been called.

Extension functions

setObserver

Cmn 
@ExperimentalComposeRuntimeApi
fun Composition.setObserver(observer: CompositionObserver): CompositionObserverHandle?

Observe the composition. Calling this twice on the same composition will implicitly dispose the previous observer. the CompositionObserver will be called for this composition and all sub-composition, transitively, for which this composition is a context. If setObserver is called on a sub-composition, it will override the parent composition observer for itself and all its sub-compositions.

Parameters
observer: CompositionObserver

the observer that will be informed of composition events for this composition and all sub-compositions for which this composition is the composition context. Observing a composition will prevent the parent composition's observer from receiving composition events about this composition.
Returns
CompositionObserverHandle?

a handle that allows the observer to be disposed and detached from the composition. Disposing an observer for a composition with a parent observer will begin sending the events to the parent composition's observer. A null indicates the composition does not support being observed.