SearchView filter with RecyclerView

Question

I have tried to implement a SearchView with suggestions (filter) in Fragment, but I have not managed it. I tried almost every tutorial but nothing worked for me. I would appreciate any help. Thank you

XML ...

    <!--appBar layout-->
    <android.support.design.widget.AppBarLayout
        android:id="@+id/appBarLayout"
        android:fitsSystemWindows="true"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize">

        <!--searchView layout-->
        <android.support.v7.widget.SearchView
            android:id="@+id/search_view"
            app:layout_scrollFlags="scroll|enterAlways"
            android:iconifiedByDefault="false"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:closeIcon="@drawable/ic_clear_white_18dp"
            app:searchIcon="@drawable/ic_search_white_24dp"
            app:queryHint="@string/search_contact"
            app:iconifiedByDefault="false"
            android:background="@color/colorPrimary"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
            app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" />

       </android.support.design.widget.AppBarLayout>

        <!-- recycler view-->
        <android.support.v7.widget.RecyclerView
            app:layout_behavior="@string/appbar_scrolling_view_behavior"
            android:id="@+id/recycler_view"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />

Fragment

@Override
    public View onCreateView(LayoutInflater inflater, final ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_contact_list, container, false);

        searchView = (SearchView)view.findViewById(R.id.search_view);
        fabButton = (FloatingActionButton)view.findViewById(R.id.fab_button);

        //recycler view
        recyclerView = (RecyclerView)view.findViewById(R.id.recycler_view);
        recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
        contacts = SugarRecord.listAll(Contact.class);
        contactsAdapter = new ContactsAdapter(getActivity(), contacts);
        recyclerView.setAdapter(contactsAdapter);

        searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
            @Override
            public boolean onQueryTextSubmit(String query) {
                return false;
            }

            @Override
            public boolean onQueryTextChange(String newText) {
                // TODO: setFilter

                return true;
            }
        });

        return view;

Adapter

public class ContactsAdapter extends RecyclerView.Adapter<ContactsAdapter.ContactVH> {

    List<Contact> mContact;
    List<Contact> mContactFilter;

    Context mContext;

    public ContactsAdapter(Context context, List<Contact> contact) {
        this.mContact = contact;
        this.mContext = context;
    }

    @Override
    public ContactVH onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.row_item_contact, parent, false);
        ContactVH viewHolder = new ContactVH(view);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(ContactVH holder, int position) {
        holder.name.setText(mContact.get(position).getName());
    }

    @Override
    public int getItemCount() {
        return mContact.size();
    }

    class ContactVH extends RecyclerView.ViewHolder {
        @BindView(R.id.contact_name)
        TextView name;

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

    }

}

Answer 1

You can create class which extends Filter

class YourFilterClass extends Filter {

private List<Contact> contactList;
private List<Contact> filteredContactList;
private ContactsAdapter adapter;

    public YourFilterClass(List<Contact> contactList, ContactsAdapter adapter) {
     this.adapter = adapter;
     this.contactList = contactList;
     this.filteredContactList = new ArrayList();
    }

    @Override
    protected FilterResults performFiltering(CharSequence constraint) {
    filteredContactList.clear();
    final FilterResults results = new FilterResults();

    //here you need to add proper items do filteredContactList
     for (final Contact item : contactList) {
            if (item.getName().toLowerCase().trim().contains("pattern")) { 
                filteredContactList.add(item);
            }
        }

        results.values = filteredContactList;
        results.count = filteredContactList.size();
        return results;
    }

    @Override
    protected void publishResults(CharSequence constraint, FilterResults results) {
        adapter.setList(filteredContactList);
        adapter.notifyDataSetChanged();
    }

}

And then you can add this Filter to yours ContactsAdapter.

public class ContactsAdapter extends RecyclerView.Adapter<ContactsAdapter.ContactVH> {

List<Contact> mContact;
List<Contact> mContactFilter;
YourFilterClass filter;

Context mContext;

public ContactsAdapter(Context context, List<Contact> contact) {
    this.mContact = contact;
    this.mContactFilter = contact;
    this.mContext = context;
    filter = new YourFilterClass(mContact, this);
}

@Override
public ContactVH onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.row_item_contact, parent, false);
    ContactVH viewHolder = new ContactVH(view);
    return viewHolder;
}

@Override
public void onBindViewHolder(ContactVH holder, int position) {
    holder.name.setText(mContactFilter.get(position).getName());
}
// set adapter filtered list
public void setList(List<Contact> list) {
    this.mContactFilter = list;
}
//call when you want to filter
public void filterList(String text) {
    filter.filter(text);
}

@Override
public int getItemCount() {
    return mContactFilter.size();
}

class ContactVH extends RecyclerView.ViewHolder {
    @BindView(R.id.contact_name)
    TextView name;

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

}

}