com.mikepenz.fastadapter.commons.utils

Interface DiffCallback<Item>

All Known Implementing Classes:

DiffCallbackImpl

public interface DiffCallback<Item>

DiffCallback used to efficiently update the items inside the list with the new DiffUtils

Method Summary

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

Method Detail

areItemsTheSame

boolean areItemsTheSame(Item oldItem,
                        Item 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

Returns:

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

areContentsTheSame

boolean areContentsTheSame(Item oldItem,
                           Item 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(Item, Item) returns true for these items.

Parameters:

oldItem - the item in the old list

newItem - the item in the new list

Returns:

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

getChangePayload

java.lang.Object getChangePayload(Item oldItem,
                                  int oldItemPosition,
                                  Item newItem,
                                  int newItemPosition)

When {#areItemsTheSame(Item, Item)} returns true for two items and {#areContentsTheSame(Item, Item)} 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:

oldItemPosition - The position of the item in the old list

newItemPosition - The position of the item in the new list

Returns:

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