title: Save focus on expanded group in ExpandableListView
body: <p>I have ExpandableListview inside NavigationDrawer. When group is expanded I collapse the previous expanded group, but when group is collapsed expanded group loses the focus (position of ExpandableListview goes down). Here's the code:</p>
  
  <pre><code>@Override
  public boolean onGroupClick(ExpandableListView expandableListView, View view, int i, long l) {
  
      if (mListView.isGroupExpanded(i)) {
          mListView.collapseGroupWithAnimation(i);
      } else {
  
          mListView.expandGroupWithAnimation(i);
          if(i!=lastExpandedGroupPosition )
              mListView.collapseGroupWithAnimation(lastExpandedGroupPosition);
  
          lastExpandedGroupPosition = i;
      }
  
       return true;
  }
  </code></pre>