避免将null作为视图根(需要在膨胀的布局根元素上解析布局参数)

为根工作室传递null会给我这样的警告:

避免将null作为视图根(需要在膨胀布局的根元素上解析布局参数)

它在getGroupView中显示一个空值。请帮助。

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) {
super();
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;
}


}