LazyItemScope

open fun Modifier.animateItem(
    fadeInSpec: FiniteAnimationSpec<Float>? = spring(stiffness = Spring.StiffnessMediumLow),
    placementSpec: FiniteAnimationSpec<IntOffset>? = spring(
            stiffness = Spring.StiffnessMediumLow,
            visibilityThreshold = IntOffset.VisibilityThreshold
        ),
    fadeOutSpec: FiniteAnimationSpec<Float>? = spring(stiffness = Spring.StiffnessMediumLow)
): Modifier

This modifier animates the item appearance (fade in), disappearance (fade out) and placement changes (such as an item reordering).

You should also provide a key via LazyListScope.item/LazyListScope.items for this modifier to enable animations.

import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.lazy.items
import androidx.compose.material.Button
import androidx.compose.material.Text
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier

var list by remember { mutableStateOf(listOf("A", "B", "C")) }
Column {
    Button(onClick = { list = list + "D" }) {
        Text("Add new item")
    }
    Button(onClick = { list = list.shuffled() }) {
        Text("Shuffle")
    }
    LazyColumn {
        items(list, key = { it }) {
            Text("Item $it", Modifier.animateItem())
        }
    }
}

@ExperimentalFoundationApi
open fun Modifier.animateItemPlacement(
    animationSpec: FiniteAnimationSpec<IntOffset> = spring(
            stiffness = Spring.StiffnessMediumLow,
            visibilityThreshold = IntOffset.VisibilityThreshold
        )
): Modifier

This modifier animates the item placement within the Lazy list.

When you provide a key via LazyListScope.item/LazyListScope.items this modifier will enable item reordering animations. Aside from item reordering all other position changes caused by events like arrangement or alignment changes will also be animated.

fun Modifier.fillParentMaxHeight(
    fraction: @FloatRange(from = 0.0, to = 1.0) Float = 1.0f
): Modifier

Have the content fill the Constraints.maxHeight of the incoming measurement constraints by setting the minimum height to be equal to the maximum height multiplied by fraction. Note that, by default, the fraction is 1, so the modifier will make the content fill the whole parent height. fraction must be between 0 and 1.

Regular Modifier.fillMaxHeight can't work inside the scrolling vertically layouts as the items are measured with Constraints.Infinity as the constraints for the main axis.

fun Modifier.fillParentMaxSize(
    fraction: @FloatRange(from = 0.0, to = 1.0) Float = 1.0f
): Modifier

Have the content fill the Constraints.maxWidth and Constraints.maxHeight of the parent measurement constraints by setting the minimum width to be equal to the maximum width multiplied by fraction and the minimum height to be equal to the maximum height multiplied by fraction. Note that, by default, the fraction is 1, so the modifier will make the content fill the whole available space. fraction must be between 0 and 1.

Regular Modifier.fillMaxSize can't work inside the scrolling layouts as the items are measured with Constraints.Infinity as the constraints for the main axis.

fun Modifier.fillParentMaxWidth(
    fraction: @FloatRange(from = 0.0, to = 1.0) Float = 1.0f
): Modifier

Have the content fill the Constraints.maxWidth of the parent measurement constraints by setting the minimum width to be equal to the maximum width multiplied by fraction. Note that, by default, the fraction is 1, so the modifier will make the content fill the whole parent width. fraction must be between 0 and 1.

Regular Modifier.fillMaxWidth can't work inside the scrolling horizontally layouts as the items are measured with Constraints.Infinity as the constraints for the main axis.