E / RecyclerView: No adapter attached; skipping layout on the hour access the main menu

To produce a shopping cart in my application I did a recyclerview on my main menu to demonstrate all the products that are in the database. I am trying to link the field known as "Category" to "CarCategoryID" but when trying to do this the application ends up starting with a white page and with the error shown in the log. Does anyone know how I can solve this problem?

database here

Log

  E/RecyclerView: No adapter attached; skipping layout

Home Activity

package com.cars.evd.dealership.main;

import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Adapter;
import android.widget.TextView;
import android.widget.Toast;

import com.cars.evd.dealership.main.Common.Common;
import com.cars.evd.dealership.main.Interface.ItemClickListener;
import com.cars.evd.dealership.main.Model.Category;
import com.cars.evd.dealership.main.ViewHolder.CarViewHolder;
import com.cars.evd.dealership.main.ViewHolder.DealershipViewHolder;
import com.firebase.ui.database.FirebaseRecyclerAdapter;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.squareup.picasso.Picasso;

public class Home extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

    FirebaseDatabase database;
    DatabaseReference category;
    TextView txtFullName;

    //Load Menu
    RecyclerView recycler_menu;
    RecyclerView.LayoutManager layoutManager;

    //Firebase Adapter
    FirebaseRecyclerAdapter<Category,CarViewHolder> adapter;




    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        toolbar.setTitle("Menu");
        setSupportActionBar(toolbar);


        //Initialise Firebase
        database = FirebaseDatabase.getInstance();
        category = database.getReference("Category");

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.addDrawerListener(toggle);
        toggle.syncState();

        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);

        //Set a name for the user
        View headerView = navigationView.getHeaderView(0);
        txtFullName = (TextView)headerView.findViewById(R.id.txtFullName);
        txtFullName.setText(Common.currentuser.getName());

        //Menu Load
       recycler_menu = (RecyclerView)findViewById(R.id.recycler_menu);
       recycler_menu.setHasFixedSize(true);
       layoutManager = new LinearLayoutManager(this);
       recycler_menu.setLayoutManager(layoutManager);

       loadMenu();

    }

    private void loadMenu() {


         new FirebaseRecyclerAdapter<Category, DealershipViewHolder>(Category.class, R.layout.car_selection, DealershipViewHolder.class,category) {

                    @Override
                    protected void populateViewHolder(DealershipViewHolder viewHolder, Category model, int position) {
                        viewHolder.txtMenuName.setText(model.getName());
                        Picasso.with(getBaseContext()).load(model.getImage()).into(viewHolder.imageView);
                        final Category clickItem = model;
                        viewHolder.setItemClickListener(new ItemClickListener() {
                            @Override
                            public void onClick(View view, int position, boolean isLongClick) {
                                //Toast.makeText(Home.this,""+clickItem.getName(),Toast.LENGTH_SHORT).show();

                                Intent CarList = new Intent(Home.this,CarList.class);

                                //Relate ID as part of a relationship between cars and dealerships
                                CarList.putExtra("CarCategoryID",adapter.getRef(position).getKey());
                                startActivity(CarList);
                            }
                        });
                    }
                };
        recycler_menu.setAdapter(adapter);
    }


    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.home, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        return super.onOptionsItemSelected(item);
    }

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        // Handle navigation view item clicks here.
        int id = item.getItemId();

        if (id == R.id.nav_menu) {
            // Handle the camera action
        } else if (id == R.id.nav_cart) {

        } else if (id == R.id.nav_orders) {

        } else if (id == R.id.nav_log_out) {

        }

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }
}

CarList

package com.cars.evd.dealership.main;

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

import com.cars.evd.dealership.main.Interface.ItemClickListener;
import com.cars.evd.dealership.main.Model.Cars;
import com.cars.evd.dealership.main.Model.Category;
import com.cars.evd.dealership.main.ViewHolder.CarViewHolder;
import com.firebase.ui.database.FirebaseRecyclerAdapter;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.squareup.picasso.Picasso;

public class CarList extends AppCompatActivity {

    RecyclerView recyclerView;
    RecyclerView.LayoutManager layoutManager;

    FirebaseDatabase database;
    DatabaseReference carList;

    String CarCategoryID = "";

    FirebaseRecyclerAdapter<Cars, CarViewHolder> adapter;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_car_list);

        //FIrebase
        database= FirebaseDatabase.getInstance();
        carList = database.getReference("Cars");

        recyclerView = (RecyclerView)findViewById(R.id.recycler_cars);
        recyclerView.setHasFixedSize(true);
        layoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);

        //Get intent here
        if(getIntent() != null)
            CarCategoryID = getIntent().getStringExtra("CarCategoryID");
        if(!CarCategoryID.isEmpty() && CarCategoryID !=null){
            loadCarsList(CarCategoryID);
        }

    }

    private void loadCarsList(String CategoryId) {
        adapter = new FirebaseRecyclerAdapter<Cars, CarViewHolder>(Cars.class
                ,R.layout.car_item,CarViewHolder.class,
                carList.orderByChild("CarCategoryID").equalTo(CategoryId)) {
            @Override
            protected void populateViewHolder(CarViewHolder viewHolder, Cars model, int position) {
                viewHolder.Carname.setText(model.getName());
                Picasso.with(getBaseContext()).load(model.getImage())
                        .into(viewHolder.Car_image);
                final Cars local = model;
                viewHolder.setItemClickListener(new ItemClickListener() {
                    @Override
                    public void onClick(View view, int position, boolean isLongClick) {
                        //start new activity
                        Toast.makeText(CarList.this,local.getName(),Toast.LENGTH_SHORT).show();

                    }
                });

            }
        };
        Log.d("TAG",""+adapter.getItemCount());
        //set adapter
        recyclerView.setAdapter(adapter);
    }

}

CarViewHolder

package com.cars.evd.dealership.main.ViewHolder;

import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;

import com.cars.evd.dealership.main.Interface.ItemClickListener;

import com.cars.evd.dealership.main.R;

public class CarViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{

    public TextView Carname;
    public ImageView Car_image;

    private ItemClickListener itemClickListener;
    public CarViewHolder(View itemView) {
        super(itemView);
        Carname = (TextView)itemView.findViewById(R.id.Carname);
        Car_image = (ImageView)itemView.findViewById(R.id.Car_image);

        itemView.setOnClickListener(this);
    }

    public void setItemClickListener(ItemClickListener itemClickListener) {
        this.itemClickListener = itemClickListener;
    }

    @Override
    public void onClick(View view) {
        itemClickListener.onClick(view,getAdapterPosition(),false);

    }
}

DealershipViewHolder

package com.cars.evd.dealership.main.ViewHolder;

import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;

import com.cars.evd.dealership.main.Interface.ItemClickListener;
import com.cars.evd.dealership.main.R;



public class DealershipViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

    public TextView txtMenuName;
    public ImageView imageView;

    private ItemClickListener itemClickListener;
    public DealershipViewHolder(View itemView) {
        super(itemView);
        txtMenuName = (TextView)itemView.findViewById(R.id.dealership_name);
        imageView = (ImageView)itemView.findViewById(R.id.menu_image);
        itemView.setOnClickListener(this);

    }

    public void setItemClickListener(ItemClickListener itemClickListener) {
        this.itemClickListener = itemClickListener;
    }

    @Override
    public void onClick(View view){
        itemClickListener.onClick(view,getAdapterPosition(),false);
    }
}

Category

package com.cars.evd.dealership.main.Model;

    import java.util.jar.Attributes;


public class Category {
    private String Name;
    private String Image;

    public Category() {
    }

    public Category(String name, String image) {
        Name = name;
        Image = image;
    }

    public String getName() {
        return Name;
    }

    public void setName(String name) {
        Name = name;
    }

    public String getImage() {
        return Image;
    }

    public void setImage(String image) {
        Image = image;
    }
}

Cars

  package com.cars.evd.dealership.main.Model;

    import org.hamcrest.Description;

    public class Cars {

        private String Name, Image,Description, CarImage,CarPrice,Type, Doors,CarCategoryID;

        public Cars(String name) {
            Name = name;
        }

        public Cars(String name, String image, String description, String carImage, String carPrice, String type, String doors, String carCategoryID) {
            Name = name;
            Image = image;
            Description = description;
            CarImage = carImage;
            CarPrice = carPrice;
            Type = type;
            Doors = doors;
            CarCategoryID = carCategoryID;
        }

        public String getName() {
            return Name;
        }

        public void setName(String name) {
            Name = name;
        }

        public String getImage() {
            return Image;
        }

        public void setImage(String image) {
            Image = image;
        }

        public String getDescription() {
            return Description;
        }

        public void setDescription(String description) {
            Description = description;
        }

        public String getCarImage() {
            return CarImage;
        }

        public void setCarImage(String carImage) {
            CarImage = carImage;
        }

        public String getCarPrice() {
            return CarPrice;
        }

        public void setCarPrice(String carPrice) {
            CarPrice = carPrice;
        }

        public String getType() {
            return Type;
        }

        public void setType(String type) {
            Type = type;
        }

        public String getDoors() {
            return Doors;
        }

        public void setDoors(String doors) {
            Doors = doors;
        }

        public String getCarCategoryID() {
            return CarCategoryID;
        }

        public void setCarCategoryID(String carCategoryID) {
            CarCategoryID = carCategoryID;
        }
    }

XML Car_Item

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app ="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="200dp"
    app:cardElevation="4dp"
    android:layout_marginBottom="8dp"
    >
    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <ImageView
            android:id="@+id/Carname"
            android:scaleType="centerCrop"
            android:src="@drawable/background"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />
        <TextView
            android:id="@+id/Car_image"
            android:text="@string/name_of_car"
            android:textColor="@android:color/white"
            android:background="#4f0e0d0e"
            android:textSize="20sp"
            android:gravity="center"
            android:layout_alignParentBottom="true"

            android:layout_width="match_parent"
            android:layout_height="wrap_content" />
    </RelativeLayout>
</android.support.v7.widget.CardView>

Car_Selection XML

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app ="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="200dp"

    app:cardElevation="4dp"
    >
    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <ImageView
            android:id="@+id/menu_image"
            android:scaleType="centerCrop"
            android:src="@drawable/background"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />
        <TextView
            android:id="@+id/dealership_name"
            android:text="@string/name_of_car"
            android:textColor="@android:color/white"
            android:background="#4f0e0d0e"
            android:textSize="20sp"
            android:gravity="center"
            android:layout_alignParentBottom="true"

            android:layout_width="match_parent"
            android:layout_height="wrap_content" />
    </RelativeLayout>
</android.support.v7.widget.CardView>