SubcomposeLayout

Component in Compose Ui

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: 2024-10-22 13:47

Installation

dependencies {
   implementation("androidx.compose.ui:ui:1.8.0-alpha04")
}

Overloads

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

Parameters

name	description
modifier	[Modifier] to apply for the layout.
measurePolicy	Measure policy which provides ability to subcompose during the measuring.

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

Parameters

name	description
state	the state object to be used by the layout.
modifier	[Modifier] to apply for the layout.
measurePolicy	Measure policy which provides ability to subcompose during the measuring.

Code Example

SubcomposeLayoutSample

@Composable
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) }
        }
    }
}