[Android] Did you still using notifyDataSetChanged()?

Recyclerview -> DiffUtil -> AsyncListDiffer -> ListAdapter

Recyclerview

It’s time to delete the notifyDataSetChanged() code!

DiffUtil

Util class that calculate the difference two lists and outs a list of update.

1. areItemsTheSame : Check whether two objects represent the same item. Commonly, check theire id equality. Check First. If this return value is false, list is flicking.
2. areContentsTheSame : Check whether two items have the same data. If areItemsTheSame return is true, this method is called.

1. DiffUtil.calculateDiff() : Calculate the list of update that can convert old to new one.
2. dispatchUpdatesTo(adapter) : Share update event to adapter.

• You must replace list to new one before calling dispatchUpdatesTo method. Like example, clear(); addAll()

AsyncListDiffer

Helper for computing the difference between two lists via DiffUtil on a background thread.

• DiffUtil.ItemCallback : Callback for calculating the diff between two non-null items in a list.

1. submitList() : Pass a new List to the AdapterHelper. Adapter updates will be computed on a background thread.
2. currentList : Check current list items.

ListAdapter

RecyclerView.Adapter base class and a convenience wrapper around AsyncListDiffer.

1. You don’t need to call getItemCount() override method anymore.
2. You can call getItem(position).

Whey we need to use ListAdapter?

• You can update changed items of the list easily.
• You don’t need to care about thread.
• Code is simple!