recyclerview/androidx.recyclerview.widget/DiffUtil/ItemCallback

ItemCallback

Callback for calculating the diff between two non-null items in a list.

Callback serves two roles - list indexing, and item diffing. ItemCallback handles just the second of these, which allows separation of code that indexes into an array or List from the presentation-layer and content specific diffing code.

Parameters

<T>

Type of items to compare.

Constructors

ItemCallback

constructor()

Functions

areContentsTheSame

abstract fun areContentsTheSame(@NonNull oldItem: T, @NonNull newItem: T): Boolean

Called to check whether two items have the same data.

areItemsTheSame

abstract fun areItemsTheSame(@NonNull oldItem: T, @NonNull newItem: T): Boolean

Called to check whether two objects represent the same item.

getChangePayload

@Nullable

open fun getChangePayload(@NonNull oldItem: T, @NonNull newItem: T): Any

When areItemsTheSame returns true for two items and areContentsTheSame returns false for them, this method is called to get a payload about the change.