litho-core/com.facebook.litho.layout/LayoutFunction1

LayoutFunction1

fun interface LayoutFunction1 : LayoutFunction

A layout function for a container with exactly one child, which it receives by name.

Layout(icon) { child, c ->
  val placeable = child.measure(c)
  layout(c.maxWidth, placeable.height) {
    placeable.place(x = (c.maxWidth - placeable.width) / 2, y = 0)
  }
}

Naming the children beats indexing a list for them: measurables[0] is a lookup that can be wrong, child cannot be.

Functions

maxIntrinsicHeight

open fun IntrinsicMeasureScope.maxIntrinsicHeight(measurables: List<Measurable>, width: Int): Int

The tallest this container would like to be at width, ignoring any upper bound.

maxIntrinsicWidth

open fun IntrinsicMeasureScope.maxIntrinsicWidth(measurables: List<Measurable>, height: Int): Int

The widest this container would like to be at height, ignoring any upper bound.

measure

abstract fun MeasureScope.measure(child: Measurable, constraints: SizeConstraints)

open override fun MeasureScope.measure(measurables: List<Measurable>, constraints: SizeConstraints)

Measure the children, then say how big this container is and where each child goes.

minIntrinsicHeight

open fun IntrinsicMeasureScope.minIntrinsicHeight(measurables: List<Measurable>, width: Int): Int

The shortest this container can be at width. The other axis of minIntrinsicWidth.

minIntrinsicWidth

open fun IntrinsicMeasureScope.minIntrinsicWidth(measurables: List<Measurable>, height: Int): Int

The narrowest this container can be at height without its content breaking out of it.