ListAdapter not refreshing RecyclerView if I submit the same list with different item order

Question

I am using a RecyclerView with ListAdapter (which uses AsyncListDiffer to calculate and animate changes when list is replaced).

The problem is that if I

Answer 1

It defeats ListAdapter's purpose for automatically calculating and animating list changes when you call these lines consecutively:

submitList(null);
submitList(orderChangedList);

Meaning, you only cleared (null) the ListAdapter's currentList and then submitted ( .submitList()) a new List. Thus, no corresponding animation will be seen in this case but only a refresh of the entire RecyclerView.

Solution is to implement the .submitList( List list) method inside your ListAdapter as follows:

public void submitList(@Nullable List list) {
    mDiffer.submitList(list != null ? new ArrayList<>(list) : null);
}

This way you allow the ListAdapter to retain its currentList and have it "diffed" with the newList, thereby the calculated animations, as opposed to "diffing" with a null.

Note: However, no update animation will happen, if, of course, the newList contains the same items in the same order as the originalList.