Expandable ListView Get correct position of parent

Question

i need to get the position of an groupView by clicking on a button in the child.

some kind of:

 Parent
  -child
  -child
  -child <-Button witch onCLickListener in ExpandableBaseAdapter class
Parent
  -child
  -child
  _...

i've been searhing for hourse to solve my problem, but i dont get it. How should i get the number/name of the Parent in the action that is done in the onClicklistener?

Heres is the method in the BaseAdapter (extends BaseExpandableListAdapter)

 @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 inflater =(LayoutInflater)this._context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView=inflater.inflate(R.layout.list_item, null);
        Button save = (Button)convertView.findViewById(R.id.Button_item_hinzufuegen);
        save.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //get the groupPosition

            }
        });