ListAdapter

public abstract class ListAdapter
extends Adapter<VH extends RecyclerView.ViewHolder>

java.lang.Object
↳	android.support.v7.widget.RecyclerView.Adapter<VH extends android.support.v7.widget.RecyclerView.ViewHolder>
	↳	android.support.v7.recyclerview.extensions.ListAdapter<T, VH extends android.support.v7.widget.RecyclerView.ViewHolder>

---

RecyclerView.Adapter base class for presenting List data in a RecyclerView, including computing diffs between Lists on a background thread.

This class is a convenience wrapper around AsyncListDiffer that implements Adapter common default behavior for item access and counting.

While using a LiveData<List> is an easy way to provide data to the adapter, it isn't required - you can use submitList(List) when new lists are available.

A complete usage pattern with Room would look like this:

 @Dao
 interface UserDao {
     @Query("SELECT * FROM user ORDER BY lastName ASC")
     public abstract LiveData<List<User>> usersByLastName();
 }

 class MyViewModel extends ViewModel {
     public final LiveData<List<User>> usersList;
     public MyViewModel(UserDao userDao) {
         usersList = userDao.usersByLastName();
     }
 }

 class MyActivity extends AppCompatActivity {
     @Override
     public void onCreate(Bundle savedState) {
         super.onCreate(savedState);
         MyViewModel viewModel = ViewModelProviders.of(this).get(MyViewModel.class);
         RecyclerView recyclerView = findViewById(R.id.user_list);
         UserAdapter<User> adapter = new UserAdapter();
         viewModel.usersList.observe(this, list -> adapter.submitList(list));
         recyclerView.setAdapter(adapter);
     }
 }

 class UserAdapter extends ListAdapter<User, UserViewHolder> {
     public UserAdapter() {
         super(User.DIFF_CALLBACK);
     }
     @Override
     public void onBindViewHolder(UserViewHolder holder, int position) {
         holder.bindTo(getItem(position));
     }
     public static final DiffUtil.ItemCallback<User> DIFF_CALLBACK =
             new DiffUtil.ItemCallback<User>() {
         @Override
         public boolean areItemsTheSame(
                 @NonNull User oldUser, @NonNull User newUser) {
             // User properties may have changed if reloaded from the DB, but ID is fixed
             return oldUser.getId() == newUser.getId();
         }
         @Override
         public boolean areContentsTheSame(
                 @NonNull User oldUser, @NonNull User newUser) {
             // NOTE: if you use equals, your object must properly override Object#equals()
             // Incorrectly returning false here will result in too many animations.
             return oldUser.equals(newUser);
         }
     }
 }

Advanced users that wish for more control over adapter behavior, or to provide a specific base class should refer to AsyncListDiffer, which provides custom mapping from diff events to adapter positions.

Summary

Protected constructors
ListAdapter(ItemCallback<T> diffCallback)
ListAdapter(AsyncDifferConfig<T> config)

Public methods
int	getItemCount() Returns the total number of items in the data set held by the adapter.
void	submitList(List<T> list) Submits a new list to be diffed, and displayed.

Protected methods
T	getItem(int position)

Inherited methods

From class android.support.v7.widget.RecyclerView.Adapter final void bindViewHolder(VH holder, int position) This method internally calls onBindViewHolder(ViewHolder, int) to update the RecyclerView.ViewHolder contents with the item at the given position and also sets up some private fields to be used by RecyclerView. final VH createViewHolder(ViewGroup parent, int viewType) This method calls onCreateViewHolder(ViewGroup, int) to create a new RecyclerView.ViewHolder and initializes some private fields to be used by RecyclerView. abstract int getItemCount() Returns the total number of items in the data set held by the adapter. long getItemId(int position) Return the stable ID for the item at position. int getItemViewType(int position) Return the view type of the item at position for the purposes of view recycling. final boolean hasObservers() Returns true if one or more observers are attached to this adapter. final boolean hasStableIds() Returns true if this adapter publishes a unique long value that can act as a key for the item at a given position in the data set. final void notifyDataSetChanged() Notify any registered observers that the data set has changed. f