com.globusltd.recyclerview.diff

Interface ParameterizedDiffCallback<E>

All Known Implementing Classes:

SimpleDatasourcesDiffCallback

public interface ParameterizedDiffCallback<E>

Method Summary

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

Method Detail

areItemsTheSame

boolean areItemsTheSame(@NonNull
                        E oldItem,
                        @NonNull
                        E 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 associated with the same position as an old item.

Returns:

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

areContentsTheSame

boolean areContentsTheSame(@NonNull
                           E oldItem,
                           @NonNull
                           E 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(E, E) returns true for these items.

Parameters:

oldItem - The item in the old list.

newItem - The item in the new list associated with the same position as an old item.

Returns:

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

getChangePayload

@Nullable
Object getChangePayload(@NonNull
                                   E oldItem,
                                   @NonNull
                                   E newItem)

When #areItemsTheSame(E, E) returns true for two items and #areContentsTheSame(E, E) 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.