# ListAdapter added in[version 27.1.0](https://developer.android.com/topic/libraries/support-library/revisions) belongs to Maven artifact com.android.support:recyclerview-v7:28.0.0-alpha1 Summary:[Protected Ctors](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/ListAdapter#proctors)\|[Methods](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/ListAdapter#pubmethods)\|[Protected Methods](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/ListAdapter#promethods)\|[Inherited Methods](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/ListAdapter#inhmethods)\|[\[Expand All\]](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/ListAdapter#) # ListAdapter | This package is part of the Android[support library](https://developer.android.com/topic/libraries/support-library)which is no longer maintained. The support library has been superseded by[AndroidX](https://developer.android.com/jetpack/androidx)which is part of[Jetpack](https://developer.android.com/jetpack). We recommend using the AndroidX libraries in all new projects. You should also consider[migrating](https://developer.android.com/jetpack/androidx/migrate)existing projects to AndroidX. To find the AndroidX class that maps to this deprecated class, see the AndroidX support library[class mappings](https://developer.android.com/jetpack/androidx/migrate/class-mappings). ` public abstract class ListAdapter ` ` `` extends `[Adapter](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter)` `` ` |---|---|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | java.lang.Object ||| | ↳ | [android.support.v7.widget.RecyclerView.Adapter](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter)\ || | | ↳ | android.support.v7.recyclerview.extensions.ListAdapter\ |
*** ** * ** *** [RecyclerView.Adapter](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter)base class for presenting List data in a[RecyclerView](https://developer.android.com/reference/android/support/v7/widget/RecyclerView), including computing diffs between Lists on a background thread. This class is a convenience wrapper around[AsyncListDiffer](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/AsyncListDiffer)that implements Adapter common default behavior for item access and counting. While using a LiveData\ is an easy way to provide data to the adapter, it isn't required - you can use[submitList(List)](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/ListAdapter#submitList(java.util.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> usersByLastName(); } class MyViewModel extends ViewModel { public final LiveData> 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 adapter = new UserAdapter(); viewModel.usersList.observe(this, list -> adapter.submitList(list)); recyclerView.setAdapter(adapter); } } class UserAdapter extends ListAdapter { public UserAdapter() { super(User.DIFF_CALLBACK); } @Override public void onBindViewHolder(UserViewHolder holder, int position) { holder.bindTo(getItem(position)); } public static final DiffUtil.ItemCallback DIFF_CALLBACK = new DiffUtil.ItemCallback() { @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](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/AsyncListDiffer), which provides custom mapping from diff events to adapter positions.
## Summary | ### Protected constructors || |-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---| | ` `[ListAdapter](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/ListAdapter#ListAdapter(android.support.v7.util.DiffUtil.ItemCallback))`(`[ItemCallback](https://developer.android.com/reference/android/support/v7/util/DiffUtil.ItemCallback)` diffCallback) ` | | ` `[ListAdapter](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/ListAdapter#ListAdapter(android.support.v7.recyclerview.extensions.AsyncDifferConfig))`(`[AsyncDifferConfig](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/AsyncDifferConfig)` config) ` | | ### Public methods || |---------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | ` int` | ` `[getItemCount](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/ListAdapter#getItemCount())`() ` Returns the total number of items in the data set held by the adapter. | | ` void` | ` `[submitList](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/ListAdapter#submitList(java.util.List))`(List list) ` Submits a new list to be diffed, and displayed. | | ### Protected methods || |------|--------------------------------------------------------------------------------------------------------------------------------------------| | ` T` | ` `[getItem](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/ListAdapter#getItem(int))`(int position) ` | | ### Inherited methods | |-----------------------|---| | [![](https://developer.android.com/static/assets/images/styles/disclosure_down.png)](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/ListAdapter#)From class` `[android.support.v7.widget.RecyclerView.Adapter](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter)` ` |------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | ` final void` | ` `[bindViewHolder](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#bindViewHolder(VH, int))`(VH holder, int position) ` This method internally calls[onBindViewHolder(ViewHolder, int)](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#onBindViewHolder(VH, int))to update the[RecyclerView.ViewHolder](https://developer.android.com/reference/android/support/v7/widget/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](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#createViewHolder(android.view.ViewGroup, int))`(`[ViewGroup](https://developer.android.com/reference/android/view/ViewGroup.html)` parent, int viewType) ` This method calls[onCreateViewHolder(ViewGroup, int)](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#onCreateViewHolder(android.view.ViewGroup, int))to create a new[RecyclerView.ViewHolder](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.ViewHolder)and initializes some private fields to be used by RecyclerView. | | ` abstract int` | ` `[getItemCount](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#getItemCount())`() ` Returns the total number of items in the data set held by the adapter. | | ` long` | ` `[getItemId](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#getItemId(int))`(int position) ` Return the stable ID for the item at`position`. | | ` int` | ` `[getItemViewType](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#getItemViewType(int))`(int position) ` Return the view type of the item at`position`for the purposes of view recycling. | | ` final boolean` | ` `[hasObservers](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#hasObservers())`() ` Returns true if one or more observers are attached to this adapter. | | ` final boolean` | ` `[hasStableIds](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#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](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#notifyDataSetChanged())`() ` Notify any registered observers that the data set has changed. | | ` final void` | ` `[notifyItemChanged](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#notifyItemChanged(int, java.lang.Object))`(int position, Object payload) ` Notify any registered observers that the item at`position`has changed with an optional payload object. | | ` final void` | ` `[notifyItemChanged](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#notifyItemChanged(int))`(int position) ` Notify any registered observers that the item at`position`has changed. | | ` final void` | ` `[notifyItemInserted](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#notifyItemInserted(int))`(int position) ` Notify any registered observers that the item reflected at`position`has been newly inserted. | | ` final void` | ` `[notifyItemMoved](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#notifyItemMoved(int, int))`(int fromPosition, int toPosition) ` Notify any registered observers that the item reflected at`fromPosition`has been moved to`toPosition`. | | ` final void` | ` `[notifyItemRangeChanged](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#notifyItemRangeChanged(int, int, java.lang.Object))`(int positionStart, int itemCount, Object payload) ` Notify any registered observers that the`itemCount`items starting at position`positionStart`have changed. | | ` final void` | ` `[notifyItemRangeChanged](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#notifyItemRangeChanged(int, int))`(int positionStart, int itemCount) ` Notify any registered observers that the`itemCount`items starting at position`positionStart`have changed. | | ` final void` | ` `[notifyItemRangeInserted](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#notifyItemRangeInserted(int, int))`(int positionStart, int itemCount) ` Notify any registered observers that the currently reflected`itemCount`items starting at`positionStart`have been newly inserted. | | ` final void` | ` `[notifyItemRangeRemoved](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#notifyItemRangeRemoved(int, int))`(int positionStart, int itemCount) ` Notify any registered observers that the`itemCount`items previously located at`positionStart`have been removed from the data set. | | ` final void` | ` `[notifyItemRemoved](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#notifyItemRemoved(int))`(int position) ` Notify any registered observers that the item previously located at`position`has been removed from the data set. | | ` void` | ` `[onAttachedToRecyclerView](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#onAttachedToRecyclerView(android.support.v7.widget.RecyclerView))`(`[RecyclerView](https://developer.android.com/reference/android/support/v7/widget/RecyclerView)` recyclerView) ` Called by RecyclerView when it starts observing this Adapter. | | ` abstract void` | ` `[onBindViewHolder](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#onBindViewHolder(VH, int))`(VH holder, int position) ` Called by RecyclerView to display the data at the specified position. | | ` void` | ` `[onBindViewHolder](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#onBindViewHolder(VH, int, java.util.List))`(VH holder, int position, List payloads) ` Called by RecyclerView to display the data at the specified position. | | ` abstract VH` | ` `[onCreateViewHolder](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#onCreateViewHolder(android.view.ViewGroup, int))`(`[ViewGroup](https://developer.android.com/reference/android/view/ViewGroup.html)` parent, int viewType) ` Called when RecyclerView needs a new[RecyclerView.ViewHolder](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.ViewHolder)of the given type to represent an item. | | ` void` | ` `[onDetachedFromRecyclerView](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#onDetachedFromRecyclerView(android.support.v7.widget.RecyclerView))`(`[RecyclerView](https://developer.android.com/reference/android/support/v7/widget/RecyclerView)` recyclerView) ` Called by RecyclerView when it stops observing this Adapter. | | ` boolean` | ` `[onFailedToRecycleView](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#onFailedToRecycleView(VH))`(VH holder) ` Called by the RecyclerView if a ViewHolder created by this Adapter cannot be recycled due to its transient state. | | ` void` | ` `[onViewAttachedToWindow](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#onViewAttachedToWindow(VH))`(VH holder) ` Called when a view created by this adapter has been attached to a window. | | ` void` | ` `[onViewDetachedFromWindow](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#onViewDetachedFromWindow(VH))`(VH holder) ` Called when a view created by this adapter has been detached from its window. | | ` void` | ` `[onViewRecycled](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#onViewRecycled(VH))`(VH holder) ` Called when a view created by this adapter has been recycled. | | ` void` | ` `[registerAdapterDataObserver](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#registerAdapterDataObserver(android.support.v7.widget.RecyclerView.AdapterDataObserver))`(`[RecyclerView.AdapterDataObserver](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.AdapterDataObserver)` observer) ` Register a new observer to listen for data changes. | | ` void` | ` `[setHasStableIds](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#setHasStableIds(boolean))`(boolean hasStableIds) ` Indicates whether each item in the data set can be represented with a unique identifier of type[Long](https://developer.android.com/reference/java/lang/Long). | | ` void` | ` `[unregisterAdapterDataObserver](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter#unregisterAdapterDataObserver(android.support.v7.widget.RecyclerView.AdapterDataObserver))`(`[RecyclerView.AdapterDataObserver](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.AdapterDataObserver)` observer) ` Unregister an observer currently listening for data changes. | || | [![](https://developer.android.com/static/assets/images/styles/disclosure_down.png)](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/ListAdapter#)From class` java.lang.Object ` |-------------------|-------------------------------| | ` Object` | ` clone() ` | | ` boolean` | ` equals(Object arg0) ` | | ` void` | ` finalize() ` | | ` final Class` | ` getClass() ` | | ` int` | ` hashCode() ` | | ` final void` | ` notify() ` | | ` final void` | ` notifyAll() ` | | ` String` | ` toString() ` | | ` final void` | ` wait(long arg0, int arg1) ` | | ` final void` | ` wait(long arg0) ` | | ` final void` | ` wait() ` | || ## Protected constructors ### ListAdapter added in[version 27.1.0](https://developer.android.com/topic/libraries/support-library/revisions) ``` ListAdapter (ItemCallback diffCallback) ```

| Parameters || |----------------|-----------------------| | `diffCallback` | `ItemCallback`
| ### ListAdapter added in[version 27.1.0](https://developer.android.com/topic/libraries/support-library/revisions) ``` ListAdapter (AsyncDifferConfig config) ```

| Parameters || |----------|----------------------------| | `config` | `AsyncDifferConfig`
| ## Public methods ### getItemCount added in[version 27.1.0](https://developer.android.com/topic/libraries/support-library/revisions) ``` int getItemCount () ``` Returns the total number of items in the data set held by the adapter.
| Returns || |-------|---------------------------------------------------| | `int` | The total number of items in this adapter.
| ### submitList added in[version 27.1.0](https://developer.android.com/topic/libraries/support-library/revisions) ``` void submitList (List list) ``` Submits a new list to be diffed, and displayed. If a list is already being displayed, a diff will be computed on a background thread, which will dispatch Adapter.notifyItem events on the main thread.
| Parameters || |--------|----------------------------------------------| | `list` | `List`: The new list to be displayed.
| ## Protected methods ### getItem added in[version 27.1.0](https://developer.android.com/topic/libraries/support-library/revisions) ``` T getItem (int position) ```

| Parameters || |------------|--------------| | `position` | `int`
| | Returns || |-----|--------| | `T` |
| - ## Classes - [AsyncDifferConfig](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/AsyncDifferConfig) - [AsyncDifferConfig.Builder](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/AsyncDifferConfig.Builder) - [AsyncListDiffer](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/AsyncListDiffer) - [ListAdapter](https://developer.android.com/reference/android/support/v7/recyclerview/extensions/ListAdapter)