Sample code snippets for using mikepenz/FastAdapter library and its various features

Header.java

public class Header extends AbstractItem<Header, Header.ViewHolder> {

    String title;

    public Header(String title) {
        this.title = title;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    // FastAdapter AbstractItem methods

    @Override
    public int getType() {
        return R.id.header_text;
    }

    @Override
    public int getLayoutRes() {
        return R.layout.header_item;
    }

    @Override
    public void bindView(ViewHolder holder) {
        super.bindView(holder);

        holder.textView.setText(title);
    }

    protected static class ViewHolder extends RecyclerView.ViewHolder {
        @BindView(R.id.header_text) TextView textView;

        public ViewHolder(View itemView) {
            super(itemView);
            ButterKnife.bind(this, itemView);
        }
    }
}

header_item.xml

<?xml version="1.0" encoding="utf-8"?>
<TextView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/header_text"
    style="@style/TextAppearance.AppCompat.Caption"
    android:layout_width="match_parent"
    android:layout_height="40dp"
    android:gravity="center_vertical"
    android:paddingLeft="@dimen/activity_margin"
    android:paddingStart="@dimen/activity_margin"
    tools:background="#EFEFEF"
    tools:text="Header">

</TextView>

HeaderActivity.java

public class HeaderActivity extends AppCompatActivity {

    @BindView(R.id.toolbar) Toolbar toolbar;
    @BindView(R.id.recycler) RecyclerView recyclerView;

    private FastItemAdapter fastAdapter;
    private HeaderAdapter<Header> headerAdapter;
    private List<Mango> mangoes;

    private FooterAdapter<ProgressItem> footerAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);

        setSupportActionBar(toolbar);
        getSupportActionBar().setTitle("With Header");

        mangoes = new DummyData(this).generateData(); //Populating our Mangoes list

        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        recyclerView.setHasFixedSize(true);
        recyclerView.setItemAnimator(new DefaultItemAnimator());

        fastAdapter = new FastItemAdapter<>();
        fastAdapter.setHasStableIds(true);
        fastAdapter.withSelectable(true);

        headerAdapter = new HeaderAdapter<>();

        footerAdapter = new FooterAdapter<>(); // help manage load more progress

        recyclerView.setAdapter(footerAdapter.wrap(headerAdapter.wrap(fastAdapter)));

        int half = mangoes.size() / 2;

        fastAdapter.add(0, new Header("First half").withIdentifier(1));
        fastAdapter.add(1, mangoes.subList(0, half));
        fastAdapter.add(half + 1, new Header("Second half").withIdentifier(2));
        fastAdapter.add(half + 2, mangoes.subList(0, half));


        fastAdapter.withOnClickListener(new FastAdapter.OnClickListener<IItem>() {
            @Override
            public boolean onClick(View v, IAdapter<IItem> adapter, IItem item, int position) {

                if (item instanceof Mango) {
                    Mango mango = (Mango) item;
                    // Do what you want with your Mango here
                }
                
                return true;
            }
        });

        recyclerView.addOnScrollListener(new EndlessRecyclerOnScrollListener() {
            @Override
            public void onLoadMore(int currentPage) {
                footerAdapter.clear();
                footerAdapter.add(new ProgressItem().withEnabled(false));

                // Faking a network load
                Handler handler = new Handler();
                handler.postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        footerAdapter.clear();

                        List<Mango> newMangoes = mangoes.subList(0, 3);
                        fastAdapter.add(newMangoes);
                    }
                }, 2000);
            }
        });

        fastAdapter.withSavedInstanceState(savedInstanceState);

    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        outState = fastAdapter.saveInstanceState(outState);
        super.onSaveInstanceState(outState);
    }
}

list_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/item_card"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@drawable/selector_card"
    android:clickable="true"
    android:orientation="horizontal">

    <ImageView
        android:id="@+id/item_image"
        android:layout_width="0dp"
        android:layout_height="88dp"
        android:layout_weight="0.3"
        android:scaleType="centerCrop"
        tools:background="@color/colorAccent"/>

    <TextView
        android:id="@+id/item_title"
        style="@style/TextAppearance.AppCompat.Subhead"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="0.7"
        android:gravity="center_vertical"
        android:padding="@dimen/activity_margin"
        tools:text="Mango"/>

</LinearLayout>

MainActivity.java

public class MainActivity extends AppCompatActivity implements ItemAdapter.ItemFilterListener, ItemTouchCallback {

    @BindView(R.id.toolbar) Toolbar toolbar;
    @BindView(R.id.recycler) RecyclerView recyclerView;

    private List<Mango> mangoes;
    private FastItemAdapter<Mango> fastAdapter;

    private SimpleDragCallback dragCallback;
    private ItemTouchHelper touchHelper;

    private ActionModeHelper actionModeHelper;
    private UndoHelper undoHelper;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);

        setSupportActionBar(toolbar);
        toolbar.setTitle("Mangoes");

        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        recyclerView.setHasFixedSize(true);
        /**
         * See <a href="https://gist.github.com/alexfu/0f464fc3742f134ccd1e">DividerItemDecoration</a>
         */
        recyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL_LIST));
        recyclerView.setItemAnimator(new DefaultItemAnimator());

        mangoes = new DummyData(this).generateData(); //Populating our Mangoes list

        fastAdapter = new FastItemAdapter<>();
        fastAdapter.setHasStableIds(true);
        fastAdapter.withSelectable(true);
        fastAdapter.withMultiSelect(true);
        fastAdapter.withSelectOnLongClick(true);

        fastAdapter.withOnClickListener(new FastAdapter.OnClickListener<Mango>() {
            @Override
            public boolean onClick(View v, IAdapter<Mango> adapter, Mango item, int position) {
                //@// TODO: Handle normal clicks: Intent to DetailActivity
                return false;
            }
        });

        fastAdapter.withFilterPredicate(new IItemAdapter.Predicate<Mango>() {
            @Override
            public boolean filter(Mango item, CharSequence constraint) {
                // Remove those which return true
                return item.getName().startsWith(String.valueOf(constraint));
            }
        });

        // Drag and drop setup
        dragCallback = new SimpleDragCallback(this);
        touchHelper = new ItemTouchHelper(dragCallback);
        touchHelper.attachToRecyclerView(recyclerView);

        // Init for multi-select CAB mode
        actionModeHelper = new ActionModeHelper(fastAdapter, R.menu.cab, new ActionBarCallBack());

        fastAdapter.withOnPreClickListener(new FastAdapter.OnClickListener<Mango>() {
            @Override
            public boolean onClick(View v, IAdapter<Mango> adapter, Mango item, int position) {
                Boolean res = actionModeHelper.onClick(item);
                return res != null ? res : false;
            }
        });

        fastAdapter.withOnPreLongClickListener(new FastAdapter.OnLongClickListener<Mango>() {
            @SuppressWarnings("ConstantConditions")
            @Override
            public boolean onLongClick(View v, IAdapter<Mango> adapter, Mango item, int position) {
                ActionMode actionMode = actionModeHelper.onLongClick(MainActivity.this, position);

                if (actionMode != null) {
                    // Set CAB background color
                    findViewById(R.id.action_mode_bar).setBackgroundColor(Color.GRAY);
                }
                return actionMode != null;
            }
        });

        /*
         For handling multiple selected items deletion via CAB mode.
         Also for Undo delete action via SnackBar
          */
        //noinspection unchecked
        undoHelper = new UndoHelper(fastAdapter, new UndoHelper.UndoListener<Mango>() {
            @Override
            public void commitRemove(Set<Integer> positions, ArrayList<FastAdapter.RelativeInfo<Mango>> removed) {
                Log.d("remove", "removed: " + removed.size());
            }
        });


        recyclerView.setAdapter(fastAdapter); // Used for single adapter type

        fastAdapter.add(mangoes); // Always add items after setting adapter

        // Call only after adding items
        fastAdapter.withSavedInstanceState(savedInstanceState);
        
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        outState = fastAdapter.saveInstanceState(outState);
        super.onSaveInstanceState(outState);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.main_menu_filter:
                // Ideally call this from your SearchView's 'onQuerytextSubmit()' & 'onQueryTextChange()'
                fastAdapter.filter("K");
                return true;

            case R.id.main_menu_next:
                Intent i = new Intent(MainActivity.this, HeaderActivity.class);
                startActivity(i);
                return true;

            default:
                return super.onOptionsItemSelected(item);
        }
    }

    // ItemAdapter.ItemFilterListener
    @Override
    public void itemsFiltered() {
        // Items filtering completed
        Toast.makeText(MainActivity.this, "Filtered", Toast.LENGTH_SHORT).show();
    }

    // ItemTouchCallback
    @Override
    public boolean itemTouchOnMove(int oldPosition, int newPosition) {
        Collections.swap(fastAdapter.getAdapterItems(), oldPosition, newPosition); // change position
        fastAdapter.notifyAdapterItemMoved(oldPosition, newPosition);
        return true;
    }

    // inner class for handling CAB
    private class ActionBarCallBack implements ActionMode.Callback {
        @Override
        public boolean onCreateActionMode(ActionMode mode, Menu menu) {
            return true;
        }

        @Override
        public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
            return false;
        }

        @Override
        public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
            undoHelper.remove(findViewById(android.R.id.content), "Item removed", "Undo", Snackbar.LENGTH_LONG, fastAdapter.getSelections());
            mode.finish();
            return true;
        }

        @Override
        public void onDestroyActionMode(ActionMode mode) {

        }
    }
}

Mango.java

public class Mango extends AbstractItem<Mango, Mango.ViewHolder> {

    private String name, imageUrl, description;


    public Mango() {
    }
    

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getImageUrl() {
        return imageUrl;
    }

    public void setImageUrl(String imageUrl) {
        this.imageUrl = imageUrl;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }


    // Fast Adapter AbstractItem methods

    @Override
    public int getType() {
        return R.id.item_card;
    }

    @Override
    public int getLayoutRes() {
        return R.layout.list_item;
    }

    @Override
    public void bindView(ViewHolder holder) {
        super.bindView(holder);

        holder.text.setText(name);

        // Doing a simple check, useful for Header view
        if (imageUrl.equals("header")) {
            holder.image.setVisibility(View.GONE);
        } else {
            Glide
                    .with(holder.itemView.getContext())
                    .load(imageUrl)
                    .diskCacheStrategy(DiskCacheStrategy.ALL)
                    .into(holder.image);
        }
    }

    protected static class ViewHolder extends RecyclerView.ViewHolder {
        @BindView(R.id.item_image) ImageView image;
        @BindView(R.id.item_title) TextView text;

        public ViewHolder(View itemView) {
            super(itemView);
            ButterKnife.bind(this, itemView);
        }
    }

}

styles.xml

<resources>

    <style name="AppTheme" parent="Base.AppTheme"></style>

    <style name="Base.AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
        <item name="windowActionBar">false</item>
        <item name="windowActionBarOverlay">true</item>
        <item name="windowNoTitle">true</item>
        <item name="android:windowBackground">@color/bgLight</item>
        <item name="windowActionModeOverlay">true</item>
    </style>

</resources>

can not resolve symbol AbstractItem in android studio

antonio10, read the article https://blog.iamsuleiman.com/recyclerview-adapter-android-made-fast-easy/ on how to setup FastAdapter library to fix that problem

Which version of FastAdapter is used in your sample?

At the time of writing the article, it was version 1.5.2