recyclerview/androidx.recyclerview.widget/RecyclerView/ItemAnimator

ItemAnimator

This class defines the animations that take place on items as changes are made to the adapter. Subclasses of ItemAnimator can be used to implement custom animations for actions on ViewHolder items. The RecyclerView will manage retaining these items while they are being animated, but implementors must call dispatchAnimationFinished when a ViewHolder's animation is finished. In other words, there must be a matching dispatchAnimationFinished call for each animateAppearance(), animateChange()animatePersistence(), and animateDisappearance() call.

By default, RecyclerView uses DefaultItemAnimator.

Inheritors

SimpleItemAnimator

Constructors

ItemAnimator

constructor()

Types

AdapterChanges

@Retention(value = RetentionPolicy.SOURCE)

annotation class AdapterChanges

The set of flags that might be passed to recordPreLayoutInformation.

ItemAnimatorFinishedListener

interface ItemAnimatorFinishedListener

This interface is used to inform listeners when all pending or running animations in an ItemAnimator are finished.

ItemHolderInfo

open class ItemHolderInfo

A simple data structure that holds information about an item's bounds.

Properties

FLAG_APPEARED_IN_PRE_LAYOUT

val FLAG_APPEARED_IN_PRE_LAYOUT: Int = 4096

This ViewHolder was not laid out but has been added to the layout in pre-layout state by the LayoutManager.

FLAG_CHANGED

val FLAG_CHANGED: Int = 2

The Item represented by this ViewHolder is updated.

FLAG_INVALIDATED

val FLAG_INVALIDATED: Int = 4

Adapter notifyDataSetChanged has been called and the content represented by this ViewHolder is invalid.

FLAG_MOVED

val FLAG_MOVED: Int = 2048

The position of the Item represented by this ViewHolder has been changed.

FLAG_REMOVED

val FLAG_REMOVED: Int = 8

The Item represented by this ViewHolder is removed from the adapter.

Functions

animateAppearance

abstract fun animateAppearance(@NonNull viewHolder: RecyclerView.ViewHolder, @Nullable preLayoutInfo: RecyclerView.ItemAnimator.ItemHolderInfo, @NonNull postLayoutInfo: RecyclerView.ItemAnimator.ItemHolderInfo): Boolean

Called by the RecyclerView when a ViewHolder is added to the layout.

animateChange

abstract fun animateChange(@NonNull oldHolder: RecyclerView.ViewHolder, @NonNull newHolder: RecyclerView.ViewHolder, @NonNull preLayoutInfo: RecyclerView.ItemAnimator.ItemHolderInfo, @NonNull postLayoutInfo: RecyclerView.ItemAnimator.ItemHolderInfo): Boolean

Called by the RecyclerView when an adapter item is present both before and after the layout and RecyclerView has received a notifyItemChanged call for it.

animateDisappearance

abstract fun animateDisappearance(@NonNull viewHolder: RecyclerView.ViewHolder, @NonNull preLayoutInfo: RecyclerView.ItemAnimator.ItemHolderInfo, @Nullable postLayoutInfo: RecyclerView.ItemAnimator.ItemHolderInfo): Boolean

Called by the RecyclerView when a ViewHolder has disappeared from the layout.

animatePersistence

abstract fun animatePersistence(@NonNull viewHolder: RecyclerView.ViewHolder, @NonNull preLayoutInfo: RecyclerView.ItemAnimator.ItemHolderInfo, @NonNull postLayoutInfo: RecyclerView.ItemAnimator.ItemHolderInfo): Boolean

Called by the RecyclerView when a ViewHolder is present in both before and after the layout and RecyclerView has not received a notifyItemChanged call for it or a notifyDataSetChanged call.

canReuseUpdatedViewHolder

open fun canReuseUpdatedViewHolder(@NonNull viewHolder: RecyclerView.ViewHolder): Boolean

open fun canReuseUpdatedViewHolder(@NonNull viewHolder: RecyclerView.ViewHolder, @NonNull payloads: List<Any>): Boolean

When an item is changed, ItemAnimator can decide whether it wants to re-use the same ViewHolder for animations or RecyclerView should create a copy of the item and ItemAnimator will use both to run the animation (e.g.

dispatchAnimationFinished