Error sending an Integer data from one fragment to another

I'm doing an App where I show a catalog of products. Every time I go into one, I select any product I skip a NullPointerException when what should happen is that it goes from fragment with the list of products to fragment with the detail of the selected object.

//// ERROR ////

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.usuario.alfapharmashop, PID: 4634
    java.lang.NullPointerException: Attempt to invoke interface method 'void com.example.usuario.alfapharmashop.Interfaces.IComunicaFragments.enviarIdProducto(int)' on a null object reference
        at com.example.usuario.alfapharmashop.Fragments.GaleriaProductosFragment$1.onClick(GaleriaProductosFragment.java:186)
        at com.example.usuario.alfapharmashop.Adapters.ProductosAdapter.onClick(ProductosAdapter.java:59)
        at android.view.View.performClick(View.java:6312)
        at android.view.View$PerformClick.run(View.java:24811)
        at android.os.Handler.handleCallback(Handler.java:790)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:171)
        at android.app.ActivityThread.main(ActivityThread.java:6651)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:547)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:824)
I/Process: Sending signal. PID: 4634 SIG: 9
Application terminated.

I leave the classes involved in the process

////////////////
//MainActivity//
////////////////

    package com.example.usuario.alfapharmashop.Interfaces;

    import android.support.v4.app.FragmentManager;
    import android.net.Uri;
    import android.os.Bundle;
    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 com.example.usuario.alfapharmashop.Fragments.CarritoFragment;
    import com.example.usuario.alfapharmashop.Fragments.DetallesProductoFragment;
    import com.example.usuario.alfapharmashop.Fragments.GaleriaCategoriaFragment;
    import com.example.usuario.alfapharmashop.Fragments.GaleriaProductosFragment;
    import com.example.usuario.alfapharmashop.Fragments.PerfilFragment;
    import com.example.usuario.alfapharmashop.R;

    public class MainActivity extends AppCompatActivity
           implements 

 NavigationView.OnNavigationItemSelectedListener,GaleriaCategoriaFragment.OnFrag
  mentInteractionListener, GaleriaProductosFragment.OnFragmentInteractionListener,
           PerfilFragment.OnFragmentInteractionListener, 
   CarritoFragment.OnFragmentInteractionListener, 
   DetallesProductoFragment.OnFragmentInteractionListener , IComunicaFragments{

    public static FragmentManager fragmentManager;

    GaleriaCategoriaFragment fragmentGaleria = null;
    PerfilFragment fragmentPerfil = null;
    CarritoFragment fragmentCarrito = null;
    GaleriaProductosFragment fragmentGaleriaProductos = null;
    DetallesProductoFragment fragmentDetalleProducto = null;

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

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        fragmentManager = getSupportFragmentManager();


        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);

        //elimina el color negro en los iconos del menĂº
        navigationView.setItemIconTintList(null);

    }

    @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.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {

        Boolean fragmentoGaleriaSelec = false;
        Boolean fragmentoCarritoSelec = false;
        Boolean fragmentoPerfilSelec = false;

        // Handle navigation view item clicks here.
        int id = item.getItemId();

        if (id == R.id.nav_perfil) {

            fragmentPerfil = new PerfilFragment();
            fragmentoPerfilSelec = true;
        } else if (id == R.id.nav_productos) {

            fragmentGaleria = new GaleriaCategoriaFragment();
            fragmentoGaleriaSelec = true;

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

            fragmentCarrito = new CarritoFragment();
            fragmentoCarritoSelec = true;

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


        }

        if(fragmentoGaleriaSelec==true){
            getSupportFragmentManager().beginTransaction().replace(R.id.content_main, fragmentGaleria).addToBackStack(null).commit();
        }else if(fragmentoCarritoSelec==true){
            getSupportFragmentManager().beginTransaction().replace(R.id.content_main, fragmentCarrito).addToBackStack(null).commit();
        }else if(fragmentoPerfilSelec==true){
            getSupportFragmentManager().beginTransaction().replace(R.id.content_main, fragmentPerfil).addToBackStack(null).commit();

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


    @Override
    public void onFragmentInteraction(Uri uri) {

    }

    @Override
    public void enviarNombreCategoria(String categoria){
        fragmentGaleriaProductos= new GaleriaProductosFragment();

        Bundle bundle = new Bundle();
        bundle.putString("categoriaProductos",categoria);
        fragmentGaleriaProductos.setArguments(bundle);
        getSupportFragmentManager().beginTransaction().replace(R.id.content_main, fragmentGaleriaProductos).addToBackStack(null).commit();

    }

    @Override
    public void enviarIdProducto(int id) {
        fragmentDetalleProducto = new DetallesProductoFragment();

        Bundle bundle = new Bundle();
        bundle.putInt("productoDetalle", id);
        fragmentDetalleProducto.setArguments(bundle);
        getSupportFragmentManager().beginTransaction().replace(R.id.content_main, fragmentDetalleProducto).addToBackStack(null).commit();
    }
}

//////////////////////////////// // INTERFACE IComunicaFragments // ////////////////////////////////

package com.example.usuario.alfapharmashop.Interfaces;

public interface IComunicaFragments {
    void enviarNombreCategoria(String categoria);
    void enviarIdProducto(int id);
}

//////////////////////////// // GalleryProductsFragment // ////////////////////////////

    package com.example.usuario.alfapharmashop.Fragments;

    import android.app.ProgressDialog;
    import android.content.Context;
    import android.net.Uri;
    import android.os.Bundle;
    import android.support.v4.app.Fragment;
    import android.support.v7.widget.GridLayoutManager;
    import android.support.v7.widget.RecyclerView;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.GridLayout;
    import android.widget.Toast;

    import com.android.volley.Request;
    import com.android.volley.Response;
    import com.android.volley.VolleyError;
    import com.android.volley.toolbox.JsonObjectRequest;
    import com.example.usuario.alfapharmashop.Adapters.ProductosAdapter;
    import com.example.usuario.alfapharmashop.Adapters.VolleySingleton;
    import com.example.usuario.alfapharmashop.Entidades.Producto;
    import com.example.usuario.alfapharmashop.Interfaces.IComunicaFragments;
    import com.example.usuario.alfapharmashop.R;

    import org.json.JSONArray;
    import org.json.JSONException;
    import org.json.JSONObject;

    import java.util.ArrayList;


    public class GaleriaProductosFragment extends Fragment implements 
    Response.ErrorListener, Response.Listener<JSONObject> {
    // TODO: Rename parameter arguments, choose names that match
    // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    public static IComunicaFragments comunicaFragments;
    private RecyclerView recyclerProductos;
    private ArrayList<Producto> listaProductos;
    private ProgressDialog dialog;
    private String nombreCat;
    // TODO: Rename and change types of parameters
    private String mParam1;
    private String mParam2;



    // RequestQueue request;
    JsonObjectRequest jsonObjectRequest;
    private OnFragmentInteractionListener mListener;

    public GaleriaProductosFragment() {
        // Required empty public constructor
    }

    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param param1 Parameter 1.
     * @param param2 Parameter 2.
     * @return A new instance of fragment GaleriaProductosFragment.
     */
    // TODO: Rename and change types and number of parameters
    public static GaleriaProductosFragment newInstance(String param1, String param2) {
        GaleriaProductosFragment fragment = new GaleriaProductosFragment();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }
    }

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

        listaProductos=new ArrayList<>();

        Bundle bundleNombreCategoria=getArguments();

        if (bundleNombreCategoria != null) {
            nombreCat = bundleNombreCategoria.getString("categoriaProductos");
        }

        recyclerProductos = (RecyclerView) vista.findViewById(R.id.idRecyclerImagen);
        recyclerProductos.setLayoutManager(new GridLayoutManager(this.getContext(), 2));

        cargarWebService(nombreCat);


        return vista;
    }

    private void cargarWebService(String categoria) {

        dialog=new ProgressDialog(getContext());
        dialog.setMessage("Cargando "+ categoria);
        dialog.incrementProgressBy(100);
        dialog.show();

        String url="https://alfapharma.000webhostapp.com/mostrarProductos.php?categoria=" + categoria;
        jsonObjectRequest=new JsonObjectRequest(Request.Method.GET,url,null,this,this);
        // request.add(jsonObjectRequest);
        VolleySingleton.getIntanciaVolley(getContext()).addToRequestQueue(jsonObjectRequest);
    }



    // TODO: Rename method, update argument and hook method into UI event
    public void onButtonPressed(Uri uri) {
        if (mListener != null) {
            mListener.onFragmentInteraction(uri);
        }
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        if (context instanceof OnFragmentInteractionListener) {
            mListener = (OnFragmentInteractionListener) context;
        } else {
            throw new RuntimeException(context.toString()
                    + " must implement OnFragmentInteractionListener");
        }
    }

    @Override
    public void onDetach() {
        super.onDetach();
        mListener = null;
    }

    @Override
    public void onErrorResponse(VolleyError error) {

    }

    @Override
    public void onResponse(JSONObject response) {
        Producto producto=null;

        JSONArray json=response.optJSONArray("producto");

        try {

            for (int i=0;i<json.length();i++){
                producto = new Producto();
                JSONObject jsonObject=null;
                jsonObject=json.getJSONObject(i);

                producto.setId(jsonObject.optInt("id"));
                producto.setNombre(jsonObject.optString("nombre"));
                producto.setDato(jsonObject.optString("img"));
                listaProductos.add(producto);
            }
            dialog.hide();
            ProductosAdapter adapter=new ProductosAdapter(listaProductos);

            adapter.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {


                    Toast.makeText(getContext(),listaProductos.get(recyclerProductos.getChildAdapterPosition(view)).getNombre()+"",Toast.LENGTH_SHORT).show();

                    comunicaFragments.enviarIdProducto(listaProductos.get(recyclerProductos.getChildAdapterPosition(view)).getId());

                }
            });

            recyclerProductos.setAdapter(adapter);

        } catch (JSONException e) {
            e.printStackTrace();
            Toast.makeText(getContext(), "No se ha podido establecer conexión con el servidor" +
                    " "+response, Toast.LENGTH_LONG).show();
            dialog.hide();
        }
    }

/**
     * This interface must be implemented by activities that contain this
     * fragment to allow an interaction in this fragment to be communicated
     * to the activity and potentially other fragments contained in that
     * activity.
     * <p>
     * See the Android Training lesson <a href=
     * "http://developer.android.com/training/basics/fragments/communicating.html"
     * >Communicating with Other Fragments</a> for more information.
     */
    public interface OnFragmentInteractionListener {
        // TODO: Update argument type and name
        void onFragmentInteraction(Uri uri);
    }
}

//////////////////////////// // DetailsProductFragment // ////////////////////////////

package com.example.usuario.alfapharmashop.Fragments;

import android.app.ProgressDialog;
import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonObjectRequest;
import com.example.usuario.alfapharmashop.Adapters.VolleySingleton;
import com.example.usuario.alfapharmashop.Entidades.Producto;
import com.example.usuario.alfapharmashop.R;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

public class DetallesProductoFragment extends Fragment implements 
Response.ErrorListener, Response.Listener<JSONObject>{
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";

// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;

private OnFragmentInteractionListener mListener;

private int idProducto;
private ImageView campoImagen;
private TextView nombreProducto;
private TextView pesoProducto;
private TextView precioProducto;
private TextView unidadesxcajaProducto;
private TextView descripcionProducto;

ProgressDialog dialog;

// RequestQueue request;
JsonObjectRequest jsonObjectRequest;

public DetallesProductoFragment() {
    // Required empty public constructor
}

/**
 * Use this factory method to create a new instance of
 * this fragment using the provided parameters.
 *
 * @param param1 Parameter 1.
 * @param param2 Parameter 2.
 * @return A new instance of fragment DetallesProductoFragment.
 */
// TODO: Rename and change types and number of parameters
public static DetallesProductoFragment newInstance(String param1, String param2) {
    DetallesProductoFragment fragment = new DetallesProductoFragment();
    Bundle args = new Bundle();
    args.putString(ARG_PARAM1, param1);
    args.putString(ARG_PARAM2, param2);
    fragment.setArguments(args);
    return fragment;
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (getArguments() != null) {
        mParam1 = getArguments().getString(ARG_PARAM1);
        mParam2 = getArguments().getString(ARG_PARAM2);
    }
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View vista = inflater.inflate(R.layout.fragment_detalles_producto, container, false);

    nombreProducto = (TextView) vista.findViewById(R.id.nombreDetalle);
    descripcionProducto= (TextView) vista.findViewById(R.id.descripcionDetalle);
    pesoProducto= (TextView) vista.findViewById(R.id.pesoDetalle);
    precioProducto= (TextView) vista.findViewById(R.id.precioDetalles);
    unidadesxcajaProducto= (TextView) vista.findViewById(R.id.unidadesxCajaDetalle);
    campoImagen = (ImageView) vista.findViewById(R.id.imagenDetalle);

    Bundle bunfleIdItem=getArguments();

    if (bunfleIdItem != null) {
        idProducto = bunfleIdItem.getInt("productoDetalle");
    }

    cargarWebService(idProducto);
    return vista;
}

private void cargarWebService(int id) {

    dialog=new ProgressDialog(getContext());
    dialog.setMessage("Buscando producto...");
    dialog.incrementProgressBy(100);
    dialog.show();

    String url="https://alfapharma.000webhostapp.com/mostrarDetalleProducto.php?id="+id;

    jsonObjectRequest=new JsonObjectRequest(Request.Method.GET,url,null,this,this);
    // request.add(jsonObjectRequest);
    VolleySingleton.getIntanciaVolley(getContext()).addToRequestQueue(jsonObjectRequest);
}


// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
    if (mListener != null) {
        mListener.onFragmentInteraction(uri);
    }
}

@Override
public void onAttach(Context context) {
    super.onAttach(context);
    if (context instanceof OnFragmentInteractionListener) {
        mListener = (OnFragmentInteractionListener) context;
    } else {
        throw new RuntimeException(context.toString()
                + " must implement OnFragmentInteractionListener");
    }
}

@Override
public void onDetach() {
    super.onDetach();
    mListener = null;
}

@Override
public void onErrorResponse(VolleyError error) {
    dialog.hide();
    Toast.makeText(getContext(),"No se pudo Consultar "+error.toString(),Toast.LENGTH_SHORT).show();
    Log.i("ERROR",error.toString());
}

@Override
public void onResponse(JSONObject response) {

    dialog.hide();

    //    Toast.makeText(getContext(),"Mensaje: "+response,Toast.LENGTH_SHORT).show();

    Producto producto=new Producto();

    JSONArray json=response.optJSONArray("detalleProductos");
    JSONObject jsonObject=null;

    try {
        jsonObject=json.getJSONObject(0);

        producto.setNombre(jsonObject.optString("nombre"));
        producto.setDescripcion(jsonObject.optString("descripcion"));
        producto.setPeso(jsonObject.optInt("peso"));
        producto.setPrecio(jsonObject.getLong("precio"));
        producto.setUnidadesxcaja(jsonObject.getInt("unidadesxcaja"));


        producto.setDato(jsonObject.optString("img"));
    } catch (JSONException e) {
        e.printStackTrace();
    }

    nombreProducto.setText(producto.getNombre());
    descripcionProducto.setText(producto.getDescripcion());
    precioProducto.setText(producto.getPrecio()+" €");
    pesoProducto.setText(producto.getPeso()+ " gr");
    unidadesxcajaProducto.setText(producto.getUnidadesxcaja()+ "Unds/caja");


    if (producto.getImagen()!=null){
        campoImagen.setImageBitmap(producto.getImagen());
    }else{
        campoImagen.setImageResource(R.drawable.nodisponible);
    }
}

/**
 * This interface must be implemented by activities that contain this
 * fragment to allow an interaction in this fragment to be communicated
 * to the activity and potentially other fragments contained in that
 * activity.
 * <p>
 * See the Android Training lesson <a href=
 * "http://developer.android.com/training/basics/fragments/communicating.html"
 * >Communicating with Other Fragments</a> for more information.
 */
public interface OnFragmentInteractionListener {
    // TODO: Update argument type and name
    void onFragmentInteraction(Uri uri);
}

}