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SubcomposeLayout

Common

Analogue of [Layout] which allows to subcompose the actual content during the measuring stage for example to use the values calculated during the measurement as params for the composition of the children.

Last updated:

Installation

dependencies {
   implementation("androidx.compose.ui:ui:1.7.0-beta04")
}

Overloads

@Composable
fun SubcomposeLayout(
    modifier: Modifier = Modifier,
    measurePolicy: SubcomposeMeasureScope.(Constraints) -> MeasureResult
)

Parameters

namedescription
modifier[Modifier] to apply for the layout.
measurePolicyMeasure policy which provides ability to subcompose during the measuring.
@UiComposable
@Composable
fun SubcomposeLayout(
    state: SubcomposeLayoutState,
    modifier: Modifier = Modifier,
    measurePolicy: SubcomposeMeasureScope.(Constraints) -> MeasureResult
)

Parameters

namedescription
statethe state object to be used by the layout.
modifier[Modifier] to apply for the layout.
measurePolicyMeasure policy which provides ability to subcompose during the measuring.

Code Example

SubcomposeLayoutSample

@Composable
@Sampled
fun SubcomposeLayoutSample(
    mainContent: @Composable () -> Unit,
    dependentContent: @Composable (IntSize) -> Unit
) {
    // enum class SlotsEnum { Main, Dependent }
    SubcomposeLayout { constraints ->
        val mainPlaceables = subcompose(SlotsEnum.Main, mainContent).map {
            it.measure(constraints)
        }
        val maxSize = mainPlaceables.fold(IntSize.Zero) { currentMax, placeable ->
            IntSize(
                width = maxOf(currentMax.width, placeable.width),
                height = maxOf(currentMax.height, placeable.height)
            )
        }
        layout(maxSize.width, maxSize.height) {
            mainPlaceables.forEach { it.placeRelative(0, 0) }
            subcompose(SlotsEnum.Dependent) {
                dependentContent(maxSize)
            }.forEach {
                it.measure(constraints).placeRelative(0, 0)
            }
        }
    }
}