How to get text on selected checkbox from listview in android

I am working on android example, when i click on checkbox then it gets the textviews value of first item(Position) in listview every time. so but i want to get value of selected (position) checkbox textview value. how to solve it please help .i am a fresher.Thanks in advances.

Some Code In BaseAdapter class

 public View getView(int position, View convertView, ViewGroup parent)
{
    ViewItem viewItem = null;
    if(convertView == null)
    {
        viewItem = new ViewItem();
        LayoutInflater layoutInfiater = (LayoutInflater)this.context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
        //LayoutInflater layoutInfiater = LayoutInflater.from(context);
        convertView = layoutInfiater.inflate(R.layout.list_adapter_view, null);

        viewItem.txtTitle = (TextView)convertView.findViewById(R.id.inactivelistview);
       // viewItem.txtDescription = (TextView)convertView.findViewById(R.id.adapter_text_description);
        convertView.setTag(viewItem);
    }
    else
    {
        viewItem = (ViewItem) convertView.getTag();
    }

    viewItem.txtTitle.setText(valueList.get(position).username);
   // viewItem.txtDescription.setText(valueList.get(position).cources_description);

    return convertView;
}

Some Code in activity

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

    listCollege = (ListView)findViewById(R.id.listCollege);
    proCollageList = (ProgressBar)findViewById(R.id.proCollageList);

    checkbox = (CheckBox)findViewById(R.id.checkbox_me);

    button  =(Button)findViewById(R.id.button1);
    new GetHttpResponse(this).execute();
}


public void onCheckboxClicked(View view) {

    boolean checked = ((CheckBox) view).isChecked();

    switch(view.getId()) {
        case R.id.checkbox_me:
            if (checked) {

                username = (TextView)findViewById(R.id.inactivelistview);

                Username =username.getText().toString();
                System.out.println("print username_=== "+Username);
                AlertDialog.Builder alertbox = new AlertDialog.Builder(this);

                alertbox.setMessage("Do you want activate "+Username+"?");

                alertbox.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                      public void onClick(DialogInterface arg0, int arg1) {
                        Toast.makeText(getApplicationContext(), Username+" acivated", Toast.LENGTH_SHORT).show();
                    }

                });

                alertbox.setNegativeButton("No", new DialogInterface.OnClickListener() {

                    public void onClick(DialogInterface arg0, int arg1) {
                        Toast.makeText(getApplicationContext(), "'No' button clicked", Toast.LENGTH_SHORT).show();
                    }
                });
               alertbox.show();
            } else
                break;
    }

I am getting textviews value of first item(Position) in listview every time. Please help me how to solve.help me update my code Thank you so much.......