Expand all children in expandable list view

You can expand it in getGroupView in your custom adapter:

@Override
public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
    View v = super.getGroupView(groupPosition, isExpanded, convertView, parent);
    ExpandableListView mExpandableListView = (ExpandableListView) parent;
    mExpandableListView.expandGroup(groupPosition);
    return v;
}

Gluck!