mva2.adapter.internal

Class DiffUtilCallback<M>

java.lang.Object

DiffUtil.Callback

mva2.adapter.internal.DiffUtilCallback<M>

public abstract class DiffUtilCallback<M>
extends DiffUtil.Callback

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	DiffUtilCallback(java.util.List<M> oldList, java.util.List<M> newList)

Method Summary

Modifier and Type	Method and Description
boolean	areContentsTheSame(int oldItemPosition, int newItemPosition)
abstract boolean	areContentsTheSame(M oldItem, M newItem) Called by the DiffUtil when it wants to check whether two items have the same data.
boolean	areItemsTheSame(int oldItemPosition, int newItemPosition)
abstract boolean	areItemsTheSame(M oldItem, M newItem) Called by the DiffUtil to decide whether two object represent the same Item.
java.lang.Object	getChangePayload(int oldItemPosition, int newItemPosition)
abstract java.lang.Object	getChangePayload(M oldItem, M newItem) When areItemsTheSame(int, int) returns true for two items and areContentsTheSame(int, int) returns false for them, DiffUtil calls this method to get a payload about the change.
int	getNewListSize()
int	getOldListSize()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DiffUtilCallback

protected DiffUtilCallback(java.util.List<M> oldList,
                           java.util.List<M> newList)

Method Detail

getOldListSize

public int getOldListSize()

getNewListSize

public int getNewListSize()

areItemsTheSame

public boolean areItemsTheSame(int oldItemPosition,
                               int newItemPosition)

areContentsTheSame

public boolean areContentsTheSame(int oldItemPosition,
                                  int newItemPosition)

getChangePayload

public java.lang.Object getChangePayload(int oldItemPosition,
                                         int newItemPosition)

areItemsTheSame

public abstract boolean areItemsTheSame(M oldItem,
                                        M newItem)

Called by the DiffUtil to decide whether two object represent the same Item.

For example, if your items have unique ids, this method should check their id equality.

Parameters:

oldItem - The item in the old list

newItem - The item in the new list which replaces the oldItem

Returns:

True if the two items represent the same object or false if they are different.

areContentsTheSame

public abstract boolean areContentsTheSame(M oldItem,
                                           M newItem)

Called by the DiffUtil when it wants to check whether two items have the same data. DiffUtil uses this information to detect if the contents of an item has changed.

DiffUtil uses this method to check equality instead of Object.equals(Object) so that you can change its behavior depending on your UI. For example, if you are using DiffUtil with a RecyclerView.Adapter, you should return whether the items' visual representations are the same.

This method is called only if areItemsTheSame(int, int) returns true for these items.

Parameters:

oldItem - The item in the old list

newItem - The item in the new list which replaces the oldItem

Returns:

True if the contents of the items are the same or false if they are different.

getChangePayload

public abstract java.lang.Object getChangePayload(M oldItem,
                                                  M newItem)

When areItemsTheSame(int, int) returns true for two items and areContentsTheSame(int, int) returns false for them, DiffUtil calls this method to get a payload about the change.

For example, if you are using DiffUtil with RecyclerView, you can return the particular field that changed in the item and your ItemAnimator can use that information to run the correct animation.

Default implementation returns null.

Parameters:

oldItem - The item in the old list

newItem - The item in the new list

Returns:

A payload object that represents the change between the two items.