可扩展ListView不在运行时更新

Question

我正在使用AsyncTask建立网址连接并向fatsecret api发送请求。 api返回一个JSON对象，我使用onPostExecute()传递给populateList（JSONArray ja）。在populateList（）方法中，我试着解析JSON数据，以便在可扩展的列表视图中可见。但是，当我致电listAdapter.notifyDataSetChanged()时，我的列表视图未更新。任何帮助都将非常感谢。我的代码如下：

 public void populateList(JSONArray ja){
     try{
        for(int i=0; i<ja.length(); i++){
            JSONObject realObj = ja.getJSONObject(i);

            foodDatas.add(realObj.getString("food_description"));
            listAdapter.notifyDataSetChanged();

            listDataHeader.add(realObj.getString("food_name"));
            listAdapter.notifyDataSetChanged();

            foodDatas.add(realObj.getString("food_type"));
            listAdapter.notifyDataSetChanged();

            listDataChild.put(listDataHeader.get(i),foodDatas);
            listAdapter.notifyDataSetChanged();
        }
    }catch (Exception exception) {
        Log.e("FatSecret Error", exception.toString());
        exception.printStackTrace();
    }
}

编辑：

这是正在使用的自定义listAdapter。

    public class ExpandableListAdapter extends BaseExpandableListAdapter {

private Context _context;
private List<String> _listDataHeader; // header titles
// child data in format of header title, child title
private HashMap<String, List<String>> _listDataChild;

public ExpandableListAdapter(Context context, List<String> listDataHeader,
                             HashMap<String, List<String>> listChildData) {
    this._context = context;
    this._listDataHeader = listDataHeader;
    this._listDataChild = listChildData;
}

@Override
public Object getChild(int groupPosition, int childPosititon) {
    return this._listDataChild.get(this._listDataHeader.get(groupPosition))
            .get(childPosititon);
}

@Override
public long getChildId(int groupPosition, int childPosition) {
    return childPosition;
}

@Override
public View getChildView(int groupPosition, final int childPosition,
                         boolean isLastChild, View convertView, ViewGroup parent) {

    final String childText = (String) getChild(groupPosition, childPosition);

    if (convertView == null) {
        LayoutInflater infalInflater = (LayoutInflater) this._context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = infalInflater.inflate(R.layout.list_item, null);
    }

    TextView txtListChild = (TextView) convertView
            .findViewById(R.id.lblListItem);

    txtListChild.setText(childText);
    return convertView;
}

@Override
public int getChildrenCount(int groupPosition) {
    return this._listDataChild.get(this._listDataHeader.get(groupPosition))
            .size();
}

@Override
public Object getGroup(int groupPosition) {
    return this._listDataHeader.get(groupPosition);
}

@Override
public int getGroupCount() {
    return this._listDataHeader.size();
}

@Override
public long getGroupId(int groupPosition) {
    return groupPosition;
}

@Override
public View getGroupView(int groupPosition, boolean isExpanded,
                         View convertView, ViewGroup parent) {
    String headerTitle = (String) getGroup(groupPosition);
    if (convertView == null) {
        LayoutInflater infalInflater = (LayoutInflater) this._context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = infalInflater.inflate(R.layout.list_group, null);
    }

    TextView lblListHeader = (TextView) convertView
            .findViewById(R.id.lblListHeader);
    lblListHeader.setTypeface(null, Typeface.BOLD);
    lblListHeader.setText(headerTitle);

    return convertView;
}

@Override
public boolean hasStableIds() {
    return false;
}

@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
    return true;
  }
}