LazyListState

class LazyListState
@ExperimentalFoundationApi
constructor(
    firstVisibleItemIndex: Int = 0,
    firstVisibleItemScrollOffset: Int = 0,
    internal val prefetchStrategy: LazyListPrefetchStrategy = LazyListPrefetchStrategy(),
) : ScrollableState

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

In most cases, this will be created via rememberLazyListState.

Parameters

Secondary Constructors

@ExperimentalFoundationApi
constructor(
    cacheWindow: LazyLayoutCacheWindow,
    firstVisibleItemIndex: Int = 0,
    firstVisibleItemScrollOffset: Int = 0,
) : this(
    firstVisibleItemIndex,
    firstVisibleItemScrollOffset,
    LazyListCacheWindowStrategy(cacheWindow),
)

Parameters

constructor(
    firstVisibleItemIndex: Int = 0,
    firstVisibleItemScrollOffset: Int = 0,
) : this(firstVisibleItemIndex, firstVisibleItemScrollOffset, LazyListPrefetchStrategy())

Parameters

Properties

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 LazyListLayoutInfo.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.

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

If you need to use it in the composition then consider wrapping the calculation into a derived state in order to only have recompositions when the derived value changes:

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.

val layoutInfo: LazyListLayoutInfo

The object of LazyListLayoutInfo 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":

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.

Functions

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

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

Parameters

fun requestScrollToItem(@AndroidXIntRange(from = 0) index: Int, scrollOffset: Int = 0)

Requests the item at index to be at the start of the viewport during the next remeasure, offset by scrollOffset, and schedules a remeasure.

The scroll position will be updated to the requested position rather than maintain the index based on the first visible item key (when a data set change will also be applied during the next remeasure), but only for the next remeasure.

Any scroll in progress will be cancelled.

Parameters

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

Animate (smooth scroll) to the given item.

Parameters

Companion Object

Properties

val Saver: Saver<LazyListState, *>

The default Saver implementation for LazyListState.