android expandlistview group imageview报错的解决办法

在expandListView的group中如果包含imageview发现，报错。提示无法将imageview转换成TextView.查看源码发现，SimpleExpandableListAdapter中有如下方法：

private void bindView(View view, Map<String, ?> data, String[] from, int[] to) {
        int len = to.length;
 
        for (int i = 0; i < len; i++) {
            TextView v = (TextView)view.findViewById(to[i]);
            if (v != null) {
                v.setText((String)data.get(from[i]));
            }
        }
    }

public class MyExpandableListAdapter extends BaseExpandableListAdapter{
        private void bindView(View view, Map<String, ?> data, String[] from, int[] to) {
                int len = to.length;
                boolean isBound = false;
                for (int i = 0; i < len; i++) {
                   final View v = view.findViewById(to[i]);
                 if (v!=null) {
                final Object _data = data.get(from[i]);
                String text = _data == null ? "" : data.toString();
                if (text == null) {
                    text = "";
                }
                          if (mViewBinder != null) {//如果Binder不为空,使用Binder进行处理
                                        isBound = mViewBinder.setViewValue(v, data.get(from[i]), text);
                                }
                                if (!isBound) {//如果Binder跳过,使用原来的方法进行处理
                                        TextView _v = (TextView)v;
                                        _v.setText((String)data.get(from[i]));
                                }                               
                        }
                }
        }
}

  @Override
	        public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
	        	  ItemViewHolder holder = null;
		           if(convertView == null){
		        	   holder=new ItemViewHolder();
		        	   convertView = inflater.inflate(R.layout.down_exam_vitem, null); 
		        	   holder.itemImg = (ImageView)convertView.findViewById(R.id.exam_vitem_img);
		        	   convertView.setTag(holder);
		           }else{
						holder = (ItemViewHolder)convertView.getTag();
		           }
		           itemView = (RelativeLayout)convertView;
		           return itemView;
	        }