List knots from firebase database

I want to list from the firebase database 2 knots: I have a knot that I call Restaurant and another Categories. In Categories I have two different knots where I put 2 knots children who in turn have children. I want to list in a recycleview the elements of each restaurant and I do not know how to do it. I want to list it by its id of the restaurant that I also have it in my database Category.

This is my code

AdapterCategory

package com.example.joserayo.myrestaurantev3.View;

import android.content.Context;
import android.support.annotation.NonNull;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import com.example.joserayo.myrestaurantev3.Model.Categorias;
import com.example.joserayo.myrestaurantev3.R;
import com.squareup.picasso.Picasso;

import java.util.List;


public class AdapterCategorias extends RecyclerView.Adapter<AdapterCategorias.categorias> {
    private List<Categorias>cate;

    private Context context1;
    private RecyclerView recyclerView;

    public  AdapterCategorias(Context context,List<Categorias> categoria){
        context1= context;
        cate=categoria;

    }

    @NonNull
    @Override
    public categorias onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view= LayoutInflater.from(parent.getContext()).inflate(R.layout.item_categoria,parent,false);
        categorias categorias=new categorias(view);

        return categorias;

    }

    @Override
    public void onBindViewHolder(@NonNull categorias holder, int position) {
        Categorias categ=cate.get(position);
        holder.nombre.setText(categ.getNombre());
        holder.descripio.setText(categ.getDescripcion());
        holder.precio.setText(categ.getPrecio());
        Picasso.with(context1).load(categ.getUrl()).fit()
                .into(holder.foto);

    }

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

    public static  class categorias extends RecyclerView.ViewHolder{

        TextView nombre, descripio,precio;
        ImageView foto;
        public categorias(View itemView) {

            super(itemView);

            nombre=(TextView)itemView.findViewById(R.id.nom);
            descripio=(TextView)itemView.findViewById(R.id.descr);
            precio=(TextView)itemView.findViewById(R.id.pre);
            foto=(ImageView)itemView.findViewById(R.id.imagenlistar);

        }
    }



}

This is my activity to list

package com.example.joserayo.myrestaurantev3.View;

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.widget.Toast;

import com.example.joserayo.myrestaurantev3.Model.Categorias;
import com.example.joserayo.myrestaurantev3.Model.CategoriasHolder;
import com.example.joserayo.myrestaurantev3.R;
import com.firebase.ui.database.FirebaseRecyclerAdapter;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.Query;
import com.google.firebase.database.ValueEventListener;

import java.util.ArrayList;
import java.util.List;

public class ListarCategorias extends AppCompatActivity  {
private RecyclerView recyclerView;
    String foodid="";
  RecyclerView.LayoutManager manager;
List<Categorias>list;
    DatabaseReference reference;
    AdapterCategorias adapter;
    private Query productQuery;

FirebaseRecyclerAdapter<Categorias,CategoriasHolder>  recyclerAdapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_listar_categorias);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
reference=FirebaseDatabase.getInstance().getReference();
        recyclerView = (RecyclerView) findViewById(R.id.myreclicleview);
         recyclerView.setHasFixedSize(true);
         manager=new LinearLayoutManager(this);
         recyclerView.setLayoutManager(manager);


        Bundle bundle = this.getIntent().getExtras();
        String idres = bundle.getString("idres");
        Log.d("Idrestau", "" + idres);
            listar(idres);
list=new ArrayList<>();



    }
    private void listar(String idres) {
        productQuery = reference.child("Categorias/bebidas")
                .orderByChild("idRestaurante").equalTo(idres);


        productQuery.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                for (DataSnapshot data:dataSnapshot.getChildren()){
                Categorias categorias= data.getValue(Categorias.class);
                    list.add(categorias);
                }
                adapter=new AdapterCategorias(ListarCategorias.this,list);
                recyclerView.setAdapter(adapter);

            }

            @Override
            public void onCancelled(DatabaseError databaseError) {
                Toast.makeText(ListarCategorias.this,databaseError.getMessage(),Toast.LENGTH_LONG);
            }
        });

                Log.d("encontrado",""+idres);

    }

firebase database knot category

database of my restaurant: