How to display multiple checkboxes into textView in another activity

This code only manage to display only one checkbox's text on the textview on the another activity. I really appreciate if somebody could help me with this. P/S: I am a newbie.

This is my current code on MainActivity:

package com.example.ujianrisiko;

import android.app.Activity;
import android.content.Intent;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;

public class MainActivity extends Activity {

//protected static final String selectedItemData = null;
Button button1;
CheckBox checkBox1, checkBox2, checkBox3, checkBox4, checkBox5, checkBox6, checkBox7, checkBox8, checkBox9, checkBox10, checkBox11, checkBox12, checkBox13, checkBox14, checkBox15, checkBox16, checkBox17;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    getActionBar().setBackgroundDrawable(new ColorDrawable(Color.parseColor("#E71E67")));

    button1 = (Button) findViewById(R.id.button1);
    checkBox1 = (CheckBox) findViewById(R.id.checkBox1);
    checkBox2 = (CheckBox) findViewById(R.id.checkBox2);
    checkBox3 = (CheckBox) findViewById(R.id.checkBox3);
    checkBox4 = (CheckBox) findViewById(R.id.checkBox4);
    checkBox5 = (CheckBox) findViewById(R.id.checkBox5);
    checkBox6 = (CheckBox) findViewById(R.id.checkBox6);
    checkBox7 = (CheckBox) findViewById(R.id.checkBox7);
    checkBox8 = (CheckBox) findViewById(R.id.checkBox8);
    checkBox9 = (CheckBox) findViewById(R.id.checkBox9);
    checkBox10 = (CheckBox) findViewById(R.id.checkBox10);
    checkBox11 = (CheckBox) findViewById(R.id.checkBox11);
    checkBox12 = (CheckBox) findViewById(R.id.checkBox12);
    checkBox13 = (CheckBox) findViewById(R.id.checkBox13);
    checkBox14 = (CheckBox) findViewById(R.id.checkBox14);
    checkBox15 = (CheckBox) findViewById(R.id.checkBox15);
    checkBox16 = (CheckBox) findViewById(R.id.checkBox16);
    checkBox17 = (CheckBox) findViewById(R.id.checkBox17);


        button1.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            //Start email activity using explicit intent
            //new Intent (From where, To where);

            Intent i=new Intent(MainActivity.this,AdviceActivity.class);
            i.putExtra("selected", checkBox1.getText().toString());
            startActivity(i);

        }
    });


}

}

And here is my code another activity:

package com.example.ujianrisiko;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.CheckBox;
import android.widget.ListView;
import android.widget.TextView;

public class AdviceActivity extends Activity {

TextView textView1, textView2;


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


    textView1= (TextView) findViewById(R.id.textView1);
    textView2= (TextView) findViewById(R.id.textView2);

    //Bundle b = getIntent().getExtras();
    //String selection = b.getString("selection");
    String selecteditem=getIntent().getExtras().getString("selected");
    textView2.setText(selecteditem);

}

}