ListState

Artifact: androidx.xr.glimmer:glimmer

View Source

Added in 1.0.0-alpha01

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Kotlin |Java

class ListState : ScrollableState

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A state object that can be hoisted to control and observe scrolling.

In most cases, this will be created via rememberListState.

Summary

Public companion properties
Saver<ListState, Any>	Saver The default Saver implementation for ListState.

Public constructors
ListState(firstVisibleItemIndex: Int, firstVisibleItemScrollOffset: Int)

Public functions
suspend Unit	animateScrollToItem(index: @IntRange(from = 0) Int, scrollOffset: Int) Animate (smooth scroll) to the given item.
open Float	dispatchRawDelta(delta: Float)
open suspend Unit	scroll(scrollPriority: MutatePriority, block: suspend ScrollScope.() -> Unit)
suspend Unit	scrollToItem(index: @IntRange(from = 0) Int, scrollOffset: Int) Instantly brings the item at index to the top of the viewport, offset by scrollOffset pixels.

Public properties
open Boolean	canScrollBackward
open Boolean	canScrollForward
Int	firstVisibleItemIndex The index of the first item that is visible within the scrollable viewport area not including items in the content padding region.
Int	firstVisibleItemScrollOffset The scroll offset of the first visible item.
InteractionSource	interactionSource InteractionSource that will be used to dispatch drag events when this list is being dragged.
open Boolean	isScrollInProgress
ListLayoutInfo	layoutInfo The object of ListLayoutInfo calculated during the last layout pass.

Inherited properties
From androidx.compose.foundation.gestures.ScrollableState open Boolean lastScrolledBackward open Boolean lastScrolledForward open ScrollIndicatorState? scrollIndicatorState

Public companion properties

Saver

Added in 1.0.0-alpha01

val Saver: Saver<ListState, Any>

The default Saver implementation for ListState.

Public constructors

ListState

Added in 1.0.0-alpha01

ListState(
    firstVisibleItemIndex: Int = 0,
    firstVisibleItemScrollOffset: Int = 0
)

Parameters
firstVisibleItemIndex: Int = 0	the initial value for ListState.firstVisibleItemIndex
firstVisibleItemScrollOffset: Int = 0	the initial value for ListState.firstVisibleItemScrollOffset

Public functions

animateScrollToItem

Added in 1.0.0-alpha01

suspend fun animateScrollToItem(index: @IntRange(from = 0) Int, scrollOffset: Int = 0): Unit

Animate (smooth scroll) to the given item.

Parameters
index: @IntRange(from = 0) Int	the index to which to scroll. Must be non-negative.
scrollOffset: Int = 0	the offset that the item should end up after the scroll. Note that positive offset refers to forward scroll, so in a top-to-bottom list, positive offset will scroll the item further upward (taking it partly offscreen).

dispatchRawDelta

Added in 1.0.0-alpha01

open fun dispatchRawDelta(delta: Float): Float

scroll

Added in 1.0.0-alpha01

open suspend fun scroll(scrollPriority: MutatePriority, block: suspend ScrollScope.() -> Unit): Unit

scrollToItem

Added in 1.0.0-alpha01

suspend fun scrollToItem(index: @IntRange(from = 0) Int, scrollOffset: Int = 0): Unit

Instantly brings the item at index to the top of the viewport, offset by scrollOffset pixels.

Parameters
index: @IntRange(from = 0) Int	the index to which to scroll. Must be non-negative.
scrollOffset: Int = 0	the offset that the item should end up after the scroll. Note that positive offset refers to forward scroll, so in a top-to-bottom list, positive offset will scroll the item further upward (taking it partly offscreen).

Public properties

canScrollBackward

open val canScrollBackward: Boolean

canScrollForward

open val canScrollForward: Boolean

firstVisibleItemIndex

Added in 1.0.0-alpha01

val firstVisibleItemIndex: Int

The index of the first item that is visible within the scrollable viewport area not including items in the content padding region. For the first visible item that includes items in the content padding please use ListLayoutInfo.visibleItemsInfo.

Note that this property is observable and if you use it in the composable function it will be recomposed on every change causing potential performance issues.

firstVisibleItemScrollOffset

Added in 1.0.0-alpha01

val firstVisibleItemScrollOffset: Int

The scroll offset of the first visible item. Scrolling forward is positive - i.e., the amount that the item is offset backwards.

Note that this property is observable and if you use it in the composable function it will be recomposed on every scroll causing potential performance issues.

interactionSource

Added in 1.0.0-alpha01

val interactionSource: InteractionSource

InteractionSource that will be used to dispatch drag events when this list is being dragged. If you want to know whether the fling (or animated scroll) is in progress, use isScrollInProgress.

isScrollInProgress

Added in 1.0.0-alpha01

open val isScrollInProgress: Boolean

layoutInfo

Added in 1.0.0-alpha01

val layoutInfo: ListLayoutInfo

The object of ListLayoutInfo calculated during the last layout pass. For example, you can use it to calculate what items are currently visible.

Note that this property is observable and is updated after every scroll or remeasure. If you use it in the composable function it will be recomposed on every change causing potential performance issues including infinity recomposition loop. Therefore, avoid using it in the composition.

If you want to run some side effects like sending an analytics event or updating a state based on this value consider using "snapshotFlow":