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ItemAnimator

abstract class ItemAnimator
kotlin.Any
   ↳ androidx.recyclerview.widget.RecyclerView.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(ViewHolder) when a ViewHolder's animation is finished. In other words, there must be a matching dispatchAnimationFinished(ViewHolder) call for each animateAppearance(), animateChange() animatePersistence(), and animateDisappearance() call.

By default, RecyclerView uses DefaultItemAnimator.

Summary

Nested classes

The set of flags that might be passed to recordPreLayoutInformation(State, ViewHolder, int, List).

abstract

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

open

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

Constants
static Int

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

static Int

The Item represented by this ViewHolder is updated.

static Int

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

static Int

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

static Int

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

Public constructors

This class defines the animations that take place on items as changes are made to the adapter.

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

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

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

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

abstract Boolean

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

abstract Boolean

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

open 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. cross-fade).

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

When an item is changed, ItemAnimator can decide whether it wants to re-use the same ViewHolder for animations or RecyclerView should create a c