gistfile1.java

@Override
public T getChild(int groupPosition, int childPosition) {		
        T value=mapList.get(getMapGroup(groupPosition)).get(childPosition);
	return value;
}

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

//Este metodo es de nosotros
protected T getMapGroup(int position){
        T value=mapList.keySet().toArray()[position];		
	return value; 
}