How to show checkbox only when getView( ) is called

Hello i'm developing simple todo list app..and I ran into this problem I want to show checkbox Dynamically but since i created it in my xml with following attributes...it is automatically shown and <CheckBox android:visibility="gone" android:layout_marginLeft="5dp" android:layout_marginTop="0dp" android:layout_width="353dp" android:layout_height="wrap_content" android:id="@+id/checkBox" android:checked="false" /> when i played with it,i figured out that listView's first row is being shown

i tried to change the visibility of checkbox but i think it is the issue with list view..

static class ViewHolder{
    TextView textView;

    ViewHolder(View v){
        textView = (TextView) v.findViewById(R.id.textView);
    }
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View row= convertView;
    ViewHolder holder = null;CheckBox checkBox;
    if(row == null){//1st time
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        row = inflater.inflate(R.layout.single_row,parent,false);
        holder = new ViewHolder(row);
        row.setTag(holder);
    }
   else{//recycling
        holder = (ViewHolder) row.getTag();
    }
    MainActivity.Task singleTask=  list.get(position);
    holder.textView.setText(singleTask.getNote());

        checkBox = (CheckBox) row.findViewById(R.id.checkBox);
    //if(position >=0)
      //  checkBox.setVisibility(View.VISIBLE);

    return row;
}

this is my arrayAdapter class... please help me with this...thanks in advance!!