RecyclerView.ItemAnimator

public static abstract class RecyclerView.ItemAnimator
extends Object

java.lang.Object
   ↳ 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

@interface RecyclerView.ItemAnimator.AdapterChanges

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

interface RecyclerView.ItemAnimator.ItemAnimatorFinishedListener

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

class RecyclerView.ItemAnimator.ItemHolderInfo

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

Constants

int FLAG_APPEARED_IN_PRE_LAYOUT

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

int FLAG_CHANGED

The Item represented by this ViewHolder is updated.

int FLAG_INVALIDATED

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

int FLAG_MOVED

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

int FLAG_REMOVED

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

Public constructors

ItemAnimator()

Public methods

abstract boolean animateAppearance(RecyclerView.ViewHolder viewHolder, RecyclerView.ItemAnimator.ItemHolderInfo preLayoutInfo, RecyclerView.ItemAnimator.ItemHolderInfo postLayoutInfo)

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

abstract boolean animateChange(RecyclerView.ViewHolder oldHolder, RecyclerView.ViewHolder newHolder, RecyclerView.ItemAnimator.ItemHolderInfo preLayoutInfo, RecyclerView.ItemAnimator.ItemHolderInfo postLayoutInfo)

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

abstract boolean animateDisappearance(RecyclerView.ViewHolder viewHolder, RecyclerView.ItemAnimator.ItemHolderInfo preLayoutInfo, RecyclerView.ItemAnimator.ItemHolderInfo postLayoutInfo)

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

abstract boolean animatePersistence(RecyclerView.ViewHolder viewHolder, RecyclerView.ItemAnimator.ItemHolderInfo preLayoutInfo, RecyclerView.ItemAnimator.ItemHolderInfo postLayoutInfo)

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

boolean canReuseUpdatedViewHolder(RecyclerView.ViewHolder viewHolder)

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.

boolean canReuseUpdatedViewHolder(RecyclerView.ViewHolder viewHolder, List<Object> payloads)

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.

final void dispatchAnimationFinished(RecyclerView.ViewHolder viewHolder)

Method to be called by subclasses when an animation is finished.

final void dispatchAnimationStarted(RecyclerView.ViewHolder viewHolder)

Method to be called by subclasses when an animation is started.

final void dispatchAnimationsFinished()

This method should be called by ItemAnimator implementations to notify any listeners that all pending and active item animations are finished.

abstract void endAnimation(RecyclerView.ViewHolder item)

Method called when an animation on a view should be ended immediately.

abstract void endAnimations()

Method called when all item animations should be ended immediately.

long getAddDuration()

Gets the current duration for which all add animations will run.

long getChangeDuration()

Gets the current duration for which all change animations will run.

long getMoveDuration()

Gets the current duration for which all move animations will run.

long getRemoveDuration()

Gets the current duration for which all remove animations will run.

abstract boolean isRunning()

Method which returns whether there are any item animations currently running.

final boolean isRunning(RecyclerView.ItemAnimator.ItemAnimatorFinishedListener listener)

Like isRunning(), this method returns whether there are any item animations currently running.

RecyclerView.ItemAnimator.ItemHolderInfo obtainHolderInfo()

Returns a new RecyclerView.ItemAnimator.ItemHolderInfo which will be used to store information about the ViewHolder.

void onAnimationFinished(RecyclerView.ViewHolder viewHolder)

Called after dispatchAnimationFinished(ViewHolder) is called by the ItemAnimator.

void onAnimationStarted(RecyclerView.ViewHolder viewHolder)

Called when a new animation is started on the given ViewHolder.

RecyclerView.ItemAnimator.ItemHolderInfo recordPostLayoutInformation(RecyclerView.State state, RecyclerView.ViewHolder viewHolder)

Called by the RecyclerView after the layout is complete.

RecyclerView.ItemAnimator.ItemHolderInfo recordPreLayoutInformation(RecyclerView.State state, RecyclerView.ViewHolder viewHolder, int changeFlags, List<Object> payloads)

Called by the RecyclerView before the layout begins.

abstract void runPendingAnimations()

Called when there are pending animations waiting to be started.

void setAddDuration(long addDuration)

Sets the duration for which all add animations will run.

void setChangeDuration(long changeDuration)

Sets the duration for which all change animations will run.

void setMoveDuration(long moveDuration)

Sets the duration for which all move animations will run.

void setRemoveDuration(long removeDuration)

Sets the duration for which all remove animations will run.

Inherited methods

Constants

FLAG_APPEARED_IN_PRE_LAYOUT

public static final int FLAG_APPEARED_IN_PRE_LAYOUT

This ViewHolder was not laid out but has been added to the layout in pre-layout state by the RecyclerView.LayoutManager. This means that the item was already in the Adapter but invisible and it may become visible in the post layout phase. LayoutManagers may prefer to add new items in pre-layout to specify their virtual location when they are invisible (e.g. to specify the item should animate in from below the visible area).

Constant Value: 4096 (0x00001000)

FLAG_CHANGED

public static final int FLAG_CHANGED

The Item represented by this ViewHolder is updated.

Constant Value: 2 (0x00000002)

FLAG_INVALIDATED

public static final int FLAG_INVALIDATED

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

Constant Value: 4 (0x00000004)

FLAG_MOVED

public static final int FLAG_MOVED

The position of the Item represented by this ViewHolder has been changed. This flag is not bound to RecyclerView.Adapter.notifyItemMoved(int, int). It might be set in response to any adapter change that may have a side effect on this item. (e.g. The item before this one has been removed from the Adapter).

Constant Value: 2048 (0x00000800)

FLAG_REMOVED

public static final int FLAG_REMOVED

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

Constant Value: 8 (0x00000008)

Public constructors

ItemAnimator