@Override
 public View getGroupView(
     int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
   if (convertView == null) {
     convertView = layoutInflater.inflate(R.layout.category_expandble_list, parent, false);
   }
   TagsCategory category = (TagsCategory) getGroup(groupPosition);
   TextView tagsCategoryName = (TextView) convertView.findViewById(R.id.elementsCategoryName);
   tagsCategoryName.setText(category.getName());
   return convertView;
 }