DefaultItemAnimator

Kotlin |Java

open class DefaultItemAnimator : SimpleItemAnimator

kotlin.Any
↳	androidx.recyclerview.widget.RecyclerView.ItemAnimator
	↳	androidx.recyclerview.widget.SimpleItemAnimator
		↳	androidx.recyclerview.widget.DefaultItemAnimator

This implementation of RecyclerView.ItemAnimator provides basic animations on remove, add, and move events that happen to the items in a RecyclerView. RecyclerView uses a DefaultItemAnimator by default.

Summary

Inherited constants

From class ItemAnimator 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 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). Int FLAG_CHANGED The Item represented by this ViewHolder is updated. Int FLAG_INVALIDATED Adapter 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. This flag is not bound to 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). Int FLAG_REMOVED The Item represented by this ViewHolder is removed from the adapter.

Public constructors
<init>() This implementation of RecyclerView.ItemAnimator provides basic animations on remove, add, and move events that happen to the items in a RecyclerView.

Public methods
open Boolean	animateAdd(holder: RecyclerView.ViewHolder!)
open Boolean	animateChange(oldHolder: RecyclerView.ViewHolder!, newHolder: RecyclerView.ViewHolder!, fromX: Int, fromY: Int, toX: Int, toY: Int)
open Boolean	animateMove(holder: RecyclerView.ViewHolder!, fromX: Int, fromY: Int, toX: Int, toY: Int)
open Boolean	animateRemove(holder: RecyclerView.ViewHolder!)
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 copy of the item and ItemAnimator will use both to run the animation (e.g. cross-fade).
open Unit	endAnimation(item: RecyclerView.ViewHolder)
open Unit	endAnimations()
open Boolean	isRunning()
open Unit	runPendingAnimations()

Inherited functions
From class SimpleItemAnimator Boolean animateAppearance(@NonNull viewHolder: RecyclerView.ViewHolder, @Nullable preLayoutInfo: RecyclerView.ItemAnimator.ItemHolderInfo?, @NonNull postLayoutInfo: RecyclerView.ItemAnimator.ItemHolderInfo) Boolean animateChange(@NonNull oldHolder: RecyclerView.ViewHolder, @NonNull newHolder: RecyclerView.ViewHolder, @NonNull preInfo: RecyclerView.ItemAnimator.ItemHolderInfo, @NonNull postInfo: RecyclerView.ItemAnimator.ItemHolderInfo) Boolean animateDisappearance(@NonNull viewHolder: RecyclerView.ViewHolder, @NonNull preLayoutInfo: RecyclerView.ItemAnimator.ItemHolderInfo, @Nullable postLayoutInfo: RecyclerView.ItemAnimator.ItemHolderInfo?) Boolean animatePersistence(@NonNull viewHolder: RecyclerView.ViewHolder, @NonNull preInfo: RecyclerView.ItemAnimator.ItemHolderInfo, @NonNull postInfo: RecyclerView.ItemAnimator.ItemHolderInfo) Boolean canReuseUpdatedViewHolder(@NonNull viewHolder: RecyclerView.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. cross-fade). Note that this method will only be called if the ViewHolder still has the same type (Adapter#getItemViewType(int)). Otherwise, ItemAnimator will always receive both ViewHolders in the animateChange(ViewHolder, ViewHolder, ItemHolderInfo, ItemHolderInfo) method. If your application is using change payloads, you can override canReuseUpdatedViewHolder(ViewHolder, List) to decide based on payloads. Unit dispatchAddFinished(item: RecyclerView.ViewHolder!) Method to be called by subclasses when an add animation is done. Unit dispatchAddStarting(item: RecyclerView.ViewHolder!) Method to be called by subclasses when an add animation is being started. Unit dispatchChangeFinished(item: RecyclerView.ViewHolder!, oldItem: Boolean) Method to be called by subclasses when a change animation is done. Unit dispatchChangeStarting(item: RecyclerView.ViewHolder!, oldItem: Boolean) Method to be called by subclasses when a change animation is being started. Unit dispatchMoveFinished(item: RecyclerView.ViewHolder!) Method to be called by subclasses when a move animation is done. Unit dispatchMoveStarting(item: RecyclerView.ViewHolder!) Method to be called by subclasses when a move animation is being started. Unit dispatchRemoveFinished(item: RecyclerView.ViewHolder!) Method to be called by subclasses when a remove animation is done. Unit dispatchRemoveStarting(item: RecyclerView.ViewHolder!) Method to be called by subclasses when a remove animation is being started. Boolean getSupportsChangeAnimations() Returns whether this ItemAnimator supports animations of change events. Unit onAddFinished(item: RecyclerView.ViewHolder!) Called when an add animation has ended on the given ViewHolder. The default implementation does nothing. Subclasses may wish to override this method to handle any ViewHolder-specific operations linked to animation lifecycles. Unit onAddStarting(item: RecyclerView.ViewHolder!) Called when an add animation is being started on the given ViewHolder. The default implementation does nothing. Subclasses may wish to override this method to handle any ViewHolder-specific operations linked to animation lifecycles. Unit onChangeFinished(item: RecyclerView.ViewHolder!, oldItem: Boolean) Called when a change animation has ended on the given ViewHolder. The default implementation does nothing. Subclasses may wish to override this method to handle any ViewHolder-specific operations linked to animation lifecycles. Unit onChangeStarting(item: RecyclerView.ViewHolder!, oldItem: Boolean) Called when a change animation is being started on the given ViewHolder. The default implementation does nothing. Subclasses may wish to override this method to handle any ViewHolder-specific operations linked to animation lifecycles. Unit onMoveFinished(item: RecyclerView.ViewHolder!) Called when a move animation has ended on the given ViewHolder. The default implementation does nothing. Subclasses may wish to override this method to handle any ViewHolder-specific operations linked to animation lifecycles. Unit onMoveStarting(item: RecyclerView.ViewHolder!) Called when a move animation is being started on the given ViewHolder. The default implementation does nothing. Subclasses may wish to override this method to handle any ViewHolder-specific operations linked to animation lifecycles. Unit onRemoveFinished(item: RecyclerView.ViewHolder!) Called when a remove animation has ended on the given ViewHolder. The default implementation does nothing. Subclasses may wish to override this method to handle any ViewHolder-specific operations linked to animation lifecycles. Unit onRemoveStarting(item: RecyclerView.ViewHolder!) Called when a remove animation is being started on the given ViewHolder. The default implementation does nothing. Subclasses may wish to override this method to handle any ViewHolder-specific operations linked to animation lifecycles. Unit setSupportsChangeAnimations(supportsChangeAnimations: Boolean) Sets whether this ItemAnimator supports animations of item change events. If you set this property to false, actions on the data set which change the contents of items will not be animated. What those animations do is left up to the discretion of the ItemAnimator subclass, in its animateChange(RecyclerView.ViewHolder, RecyclerView.ViewHolder, int, int, int, int) implementation. The value of this property is true by default.
From class ItemAnimator 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 copy of the item and ItemAnimator will use both to run the animation (e.g. cross-fade). Note that this method will only be called if the ViewHolder still has the same type (Adapter#getItemViewType(int)). Otherwise, ItemAnimator will always receive both ViewHolders in the animateChange(ViewHolder, ViewHolder, ItemHolderInfo, ItemHolderInfo) method. Unit dispatchAnimationFinished(@NonNull viewHolder: RecyclerView.ViewHolder) Method to be called by subclasses when an animation is finished. For each call RecyclerView makes to animateAppearance(), animatePersistence(), or animateDisappearance(), there should be a matching dispatchAnimationFinished(ViewHolder) call by the subclass. For animateChange(), subclass should call this method for both the oldHolder and newHolder (if they are not the same instance). Unit dispatchAnimationStarted(@NonNull viewHolder: RecyclerView.ViewHolder) Method to be called by subclasses when an animation is started. For each call RecyclerView makes to animateAppearance(), animatePersistence(), or animateDisappearance(), there should be a matching dispatchAnimationStarted(ViewHolder) call by the subclass. For animateChange(), subclass should call this method for both the oldHolder and newHolder (if they are not the same instance). If your ItemAnimator decides not to animate a ViewHolder, it should call dispatchAnimationFinished(ViewHolder) without calling dispatchAnimationStarted(ViewHolder). Unit dispatchAnimationsFinished() This method should be called by ItemAnimator implementations to notify any listeners that all pending and active item animations are finished. Unit endAnimation(@NonNull item: RecyclerView.ViewHolder) Method called when an animation on a view should be ended immediately. This could happen when other events, like scrolling, occur, so that animating views can be quickly put into their proper end locations. Implementations should ensure that any animations running on the item are canceled and affected properties are set to their end values. Also, dispatchAnimationFinished(ViewHolder) should be called for each finished animation since the animations are effectively done when this method is called. Unit endAnimations() Method called when all item animations should be ended immediately. This could happen when other events, like scrolling, occur, so that animating views can be quickly put into their proper end locations. Implementations should ensure that any animations running on any items are canceled and affected properties are set to their end values. Also, dispatchAnimationFinished(ViewHolder) should be called for each finished animation since the animations are effectively done when this method is called. 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. Boolean isRunning() Method which returns whether there are any item animations currently running. This method can be used to determine whether to delay other actions until animations end. Boolean isRunning(@Nullable listener: RecyclerView.ItemAnimator.ItemAnimatorFinishedListener?) Like isRunning(), this method returns whether there are any item animations currently running. Additionally, the listener passed in will be called when there are no item animations running, either immediately (before the method returns) if no animations are currently running, or when the currently running animations are finished. Note that the listener is transient - it is either called immediately and not stored at all, or stored only until it is called when running animations are finished sometime later. RecyclerView.ItemAnimator.ItemHolderInfo obtainHolderInfo() Returns a new ItemHolderInfo which will be used to store information about the ViewHolder. This information will later be passed into animate** methods. You can override this method if you want to extend ItemHolderInfo and provide your own instances. Unit onAnimationFinished(@NonNull viewHolder: RecyclerView.ViewHolder) Called after dispatchAnimationFinished(ViewHolder) is called by the ItemAnimator. Unit onAnimationStarted(@NonNull viewHolder: RecyclerView.ViewHolder) Called when a new animation is started on the given ViewHolder. RecyclerView.ItemAnimator.ItemHolderInfo recordPostLayoutInformation(@NonNull state: RecyclerView.State, @NonNull viewHolder: RecyclerView.ViewHolder) Called by the RecyclerView after the layout is complete. Item animator should record necessary information about the View's final state. The data returned from this method will be passed to the related animate** methods. The default implementation returns an ItemHolderInfo which holds the bounds of the View. RecyclerView.ItemAnimator.ItemHolderInfo recordPreLayoutInformation(@NonNull state: RecyclerView.State, @NonNull viewHolder: RecyclerView.ViewHolder, changeFlags: Int, @NonNull payloads: MutableList<Any!>) Called by the RecyclerView before the layout begins. Item animator should record necessary information about the View before it is potentially rebound, moved or removed. The data returned from this method will be passed to the related animate** methods. Note that this method may be called after pre-layout phase if LayoutManager adds new Views to the layout in pre-layout pass. The default implementation returns an ItemHolderInfo which holds the bounds of the View and the adapter change flags. Unit runPendingAnimations() Called when there are pending animations waiting to be started. This state is governed by the return values from animateAppearance(), animateChange() animatePersistence(), and animateDisappearance(), which inform the RecyclerView that the ItemAnimator wants to be called later to start the associated animations. runPendingAnimations() will be scheduled to be run on the next frame. Unit setAddDuration(addDuration: Long) Sets the duration for which all add animations will run. Unit setChangeDuration(changeDuration: Long) Sets the duration for which all change animations will run. Unit setMoveDuration(moveDuration: Long) Sets the duration for which all move animations will run. Unit setRemoveDuration(removeDuration: Long) Sets the duration for which all remove animations will run.

Public constructors

<init>

DefaultItemAnimator()

This implementation of RecyclerView.ItemAnimator provides basic animations on remove, add, and move events that happen to the items in a RecyclerView. RecyclerView uses a DefaultItemAnimator by default.

See Also

• RecyclerView#setItemAnimator(RecyclerView.ItemAnimator)

Public methods

animateAdd

open fun animateAdd(holder: RecyclerView.ViewHolder!): Boolean

animateChange

open fun animateChange(
    oldHolder: RecyclerView.ViewHolder!, 
    newHolder: RecyclerView.ViewHolder!, 
    fromX: Int, 
    fromY: Int, 
    toX: Int, 
    toY: Int
): Boolean

animateMove

open fun animateMove(
    holder: RecyclerView.ViewHolder!, 
    fromX: Int, 
    fromY: Int, 
    toX: Int, 
    toY: Int
): Boolean

animateRemove

open fun animateRemove(holder: RecyclerView.ViewHolder!): Boolean

canReuseUpdatedViewHolder

open fun canReuseUpdatedViewHolder(
    @NonNull viewHolder: RecyclerView.ViewHolder, 
    @NonNull payloads: MutableList<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. cross-fade).

Note that this method will only be called if the ViewHolder still has the same type (Adapter#getItemViewType(int)). Otherwise, ItemAnimator will always receive both ViewHolders in the animateChange(ViewHolder, ViewHolder, ItemHolderInfo, ItemHolderInfo) method.

If the payload list is not empty, DefaultItemAnimator returns true. When this is the case:

• If you override animateChange(RecyclerView.ViewHolder, RecyclerView.ViewHolder, int, int, int, int), both ViewHolder arguments will be the same instance.
• If you are not overriding animateChange(RecyclerView.ViewHolder, RecyclerView.ViewHolder, int, int, int, int), then DefaultItemAnimator will call animateMove(RecyclerView.ViewHolder, int, int, int, int) and run a move animation instead.

Parameters
viewHolder	RecyclerView.ViewHolder: The ViewHolder which represents the changed item's old content.
payloads	MutableList<Any!>: A non-null list of merged payloads that were sent with change notifications. Can be empty if the adapter is invalidated via RecyclerView.Adapter#notifyDataSetChanged(). The same list of payloads will be passed into RecyclerView.Adapter#onBindViewHolder(ViewHolder, int, List) method if this method returns true.

Return
Boolean	True if RecyclerView should just rebind to the same ViewHolder or false if RecyclerView should create a new ViewHolder and pass this ViewHolder to the ItemAnimator to animate. Default implementation calls canReuseUpdatedViewHolder(ViewHolder).

endAnimation

open fun endAnimation(item: RecyclerView.ViewHolder): Unit

endAnimations

open fun endAnimations(): Unit

isRunning

open fun isRunning(): Boolean

runPendingAnimations

open fun runPendingAnimations(): Unit