LazyStaggeredGridState

Class

Common

class LazyStaggeredGridState
internal constructor(
    initialFirstVisibleItems: IntArray,
    initialFirstVisibleOffsets: IntArray,
    prefetchScheduler: PrefetchScheduler?,
) : ScrollableState

Hoisted state object controlling LazyVerticalStaggeredGrid or LazyHorizontalStaggeredGrid. In most cases, it should be created via rememberLazyStaggeredGridState.

Secondary Constructors

constructor(
    initialFirstVisibleItemIndex: Int = 0,
    initialFirstVisibleItemOffset: Int = 0,
) : this(
    intArrayOf(initialFirstVisibleItemIndex),
    intArrayOf(initialFirstVisibleItemOffset),
    null,
)

Parameters


initialFirstVisibleItemIndex	initial value for `firstVisibleItemIndex`
initialFirstVisibleItemOffset	initial value for `firstVisibleItemScrollOffset`

Properties

Common

val firstVisibleItemIndex: Int

Index of the first visible item across all staggered grid lanes. This does not include items in the content padding region. For the first visible item that includes items in the content padding please use LazyStaggeredGridLayoutInfo.visibleItemsInfo.

This property is observable and when use it in composable function it will be recomposed on each scroll, potentially causing performance issues.

Common

val firstVisibleItemScrollOffset: Int

Current offset of the item with firstVisibleItemIndex relative to the container start.

This property is observable and when use it in composable function it will be recomposed on each scroll, potentially causing performance issues.

Common

val layoutInfo: LazyStaggeredGridLayoutInfo

Layout information calculated during last layout pass, with information about currently visible items and container parameters.

This property is observable and when use it in composable function it will be recomposed on each scroll, potentially causing performance issues.

Common

val 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(
        /* @IntRange(from = 0) */
        index: Int,
        scrollOffset: Int = 0,
    )

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

Parameters


index	the index to which to scroll. MUST NOT be negative.
scrollOffset	the offset where the item should end up after the scroll. Note that positive offset refers to forward scroll, so in a reversed list, positive offset will scroll the item further upward (taking it partly offscreen).

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

Animate (smooth scroll) to the given item.

Parameters


index	the index to which to scroll. MUST NOT be negative.
scrollOffset	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).

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


index	the index to which to scroll. Must be non-negative.
scrollOffset	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).

Companion Object

Properties

Common

val Saver =
        listSaver<LazyStaggeredGridState, IntArray>(
            save = { state ->
                listOf(state.scrollPosition.indices, state.scrollPosition.scrollOffsets)
            },
            restore = { LazyStaggeredGridState(it[0], it[1], null) },
        )

The default implementation of Saver for LazyStaggeredGridState