Android Post values from Recyclerview Checkbox to database

I'm working on an employee attendance attendance applicaion, for that I'm listing employee namelist from my MySQL database to android RecyclerView. Everything is working fine. But what I actually wanted is, I want to update my attendance table with the CheckBox values, my table contains 3 columns id,emp_id,emp_attn, If the checkbox is checked for an employee, the app should post it as checked ! So how can i identify each checkbox in my recyclerview,

MyAdapter.java

import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;

import java.util.List;

/**
 * Created by Akshay N Shaju on 10/20/2017.
 */

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder>{

    private List<Listitems> listitemses;
    private Context context;

    public MyAdapter(List<Listitems> listitemses, Context context) {
        this.listitemses = listitemses;
        this.context = context;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.list_item, parent, false);
        return new ViewHolder(v);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {

        final Listitems listitem = listitemses.get(position);
        holder.CbHead.setText(listitem.getHead());
        holder.textViewDesc.setText(listitem.getDesc());

        holder.CbHead.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(context,listitem.getHead(), Toast.LENGTH_LONG).show();
            }
        });
 }

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

    public  class ViewHolder extends RecyclerView.ViewHolder {
        public CheckBox CbHead;
        public TextView textViewDesc;
        public LinearLayout linearLayout;

        public ViewHolder(View itemView) {
            super(itemView);

            CbHead = (CheckBox) itemView.findViewById(R.id.CbHead);
            textViewDesc = (TextView) itemView.findViewById(R.id.textViewDisc);
            linearLayout = (LinearLayout) itemView.findViewById(R.id.LinearLyout1);
        }
    }

}

MainActivity.java

import android.app.ProgressDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.widget.Toast;

import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;

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

import java.lang.ref.ReferenceQueue;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    private static final String URL_DATA = "http://ift.tt/2grPvnP";
    private RecyclerView recyclerView;
    private RecyclerView.Adapter adapter;
    private List<Listitems> listitemses;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        listitemses = new ArrayList<>();

        loadRecyclerViewData();
        }
        private void loadRecyclerViewData(){
            final ProgressDialog progressDialog = new ProgressDialog(this);
            progressDialog.setMessage("Loading Data");
            progressDialog.show();

            StringRequest stringRequest = new StringRequest(Request.Method.GET,
                    URL_DATA,
                    new Response.Listener<String>() {
                        @Override
                        public void onResponse(String response) {
                            progressDialog.dismiss();
                            try {
                                JSONObject jsonObject = new JSONObject(response);
                                JSONArray array = jsonObject.getJSONArray("employee");
                                for(int i=0; i<array.length(); i++){
                                    JSONObject o = array.getJSONObject(i);
                                    Listitems item = new Listitems(
                                    o.getString("name"),
                                    o.getString("id"),
                                    o.getString("image")
                                            );
                                    listitemses.add(item);
                                }
                                adapter =  new MyAdapter(listitemses,getApplicationContext());
                                recyclerView.setAdapter(adapter);

                            } catch (JSONException e) {
                                e.printStackTrace();
                            }
                        }
                    },
                    new Response.ErrorListener() {
                        @Override
                        public void onErrorResponse(VolleyError error) {
                            progressDialog.dismiss();
                            Toast.makeText(getApplicationContext(),"error",Toast.LENGTH_SHORT).show();
                        }
                    });
            RequestQueue requestQueue = Volley.newRequestQueue(this);
            requestQueue.add(stringRequest);
        }
    }

Here in my adapter I tried an onClick Listner, which toast the employee name when checked and it worked ! but how can I get all the checkbox status and post it to my database table when save button clicked.