litho-widget-kotlin/com.facebook.litho.widget.collection/LazyCollectionController

LazyCollectionController

A controller that can be set on a LazyCollection to trigger external events. Most calls should be made on the main thread e.g. within a Style.onClick { } callback.

Constructors

constructor()

Properties

isRefreshing

@get:UiThread

val isRefreshing: Boolean

Tells if the refresh indicator is currently shown. Reflects the pending value when unbound.

recyclerView

@get:UiThread

val recyclerView: RecyclerView?

Retrieve a reference to the RecyclerView. This should be avoided if possible, but may be necessary e.g. for custom animations.

snapHelper

@get:UiThread

val snapHelper: SnapHelper?

A reference to the SnapHelper that is currently attached to the RecyclerView. If this LazyCollection isn't mounted or doesn't have an associated SnapHelper, returns null.

Functions

scrollBy

@UiThread

fun scrollBy(@Px dx: Int, @Px dy: Int)

Scroll the LazyCollection by a given number of pixels. The Scroll is instant. For an animated scroll use smoothScrollBy.

scrollToId

@UiThread

fun scrollToId(id: Any, @Px offset: Int = 0)

Scroll the LazyCollection so that the child with the given id is fully visible. For an animated scroll use smoothScrollToId.

scrollToIndex

@UiThread

fun scrollToIndex(index: Int, @Px offset: Int = 0)

Scroll the LazyCollection so that the child at the given index is fully visible. For an animated scroll use smoothScrollToIndex.

setRecyclerUpdate

fun setRecyclerUpdate(listener: (RecyclerView?) -> Unit)

Request a callback when a RecyclerView is bound or unbound. The listener is retained for the controller's lifetime and auto-re-attached on every underlying-controller (re)bind, so it keeps firing across rebinds — including when a retained ComponentTree is rehosted onto a new LithoView and the RecyclerView is re-mounted (tab-switch back, rotation). Callers no longer need to re-register from their own mount/lifecycle hook. Pass an empty lambda to detach.

setRefreshing

@UiThread

fun setRefreshing(isRefreshing: Boolean)

Toggle the refresh indicator. Not needed inside LazyCollection's onPullToRefresh callback — triggered automatically. Calls made before the controller binds are stashed (latest-wins) and applied once on bind.

smoothScrollBy

@UiThread

fun smoothScrollBy(@Px dx: Int, @Px dy: Int)

Perform and animated scroll on the LazyCollection by a given number of pixels. For an instantaneous scroll use scrollBy.

smoothScrollToId

@UiThread

fun smoothScrollToId(id: Any, @Px offset: Int = 0, smoothScrollAlignmentType: SmoothScrollAlignmentType = SmoothScrollAlignmentType.DEFAULT)

Perform an animated scroll on the LazyCollection so that the child with the given id is fully visible. For an animated scroll use smoothScrollToId.

smoothScrollToIndex

@UiThread

fun smoothScrollToIndex(index: Int, @Px offset: Int = 0, smoothScrollAlignmentType: SmoothScrollAlignmentType = SmoothScrollAlignmentType.DEFAULT)

Perform an animated scroll on the LazyCollection so that the child at the given index is fully visible. For an instantaneous scroll use scrollToIndex.