Problem with ExpandableListView refreshing

Question

Hi, I have problem with ExpandableListView refreshing. Everything is ok until I click on the list after calling onDataChanged(). I call this method in another class.

public class OnlineVisitorsView extends ExpandableListActivity{
MyAdapter adapter;

//SINGLETON
private static OnlineVisitorsView ourInstance;

public static OnlineVisitorsView getInstance() {
    return ourInstance;
}
//END SINGLETON

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    ourInstance = this;

    adapter = new MyAdapter(this.getBaseContext());
    setListAdapter(adapter);
}

public void onDataChanged(){
    adapter.getData();

}
}

class MyAdapter extends SimpleExpandableListAdapter{

static List<List<Map<String, Object>>> childData = new ArrayList<List<Map<String, Object>>>();
static List<Map<String, String>> groupData = new ArrayList<Map<String, String>>();

public MyAdapter (Context context)
{
  super(context,groupData,
          R.layout.grouprow,
          new String[] {"state"},
          new int[] { R.id.groupname },
          childData,
          0,
            null,
            new int[] {}
            );
   getData();

 }

OnlineVisitorsView ovv = OnlineVisitorsView.getInstance();

LayoutInflater layoutInflater = (LayoutInflater) ovv.getSystemService(Context.LAYOUT_INFLATER_SERVICE);


public void getData(){


    Map<String, String> onlineClients = new HashMap<String, String>();
    onlineClients.put("state", "Online");

    Map<String, String> invitedClients = new HashMap<String, String>();
    invitedClients.put("state", "Invited");

    Map<String, String> onChatClients = new HashMap<String, String>();
    onChatClients.put("state", "On chat");

    Map<String, String> closedClients = new HashMap<String, String>();
    closedClients.put("state", "Closed");

    Map<String, String> offlineClients = new HashMap<String, String>();
    offlineClients.put("state", "Offline");

    groupData.add(onlineClients);
    groupData.add(invitedClients);
    groupData.add(closedClients);
    groupData.add(offlineClients);

    List<Map<String, Object>> childrenOnline = new ArrayList<Map<String, Object>>();
    List<Map<String, Object>> childrenInvited = new ArrayList<Map<String, Object>>();
    List<Map<String, Object>> childrenOnChat = new ArrayList<Map<String, Object>>();
    List<Map<String, Object>> childrenClosed = new ArrayList<Map<String, Object>>();
    List<Map<String, Object>> childrenOffline = new ArrayList<Map<String, Object>>();

    Iterator<Client> iterator = OnlineVisitorsDataHandler.clientsList.iterator();
    while (iterator.hasNext()){

       Client client = iterator.next();

       //Online
       if (client.getState().equals("IWCS1001S")){
          Map<String, Object> currentChildMap = new HashMap<String, Object>();

          currentChildMap.put("host", client.getHost());
          currentChildMap.put("country", client.getCountry());
          currentChildMap.put("pageURL", client.getPageURL());

          int clientFlagInt = client.getFlag();
          currentChildMap.put("flag", ovv.getResources().getDrawable(clientFlagInt));

          int clientBrowserInt = client.getBrowser();
          currentChildMap.put("browser", ovv.getResources().getDrawable(clientBrowserInt));

          String keyWords = client.getKeyWords();
          int clientRefererInt = client.getRefererIcon();

          if (!keyWords.equals("")){
             currentChildMap.put("keyWords", keyWords);
             currentChildMap.put("refererIcon", ovv.getResources().getDrawable(clientRefererInt));

          }

          childrenOnline.add(currentChildMap);
       }

       //Invited
       if (client.getState().equals("IWCS1003S")){
          Map<String, Object> currentChildMap = new HashMap<String, Object>();

          currentChildMap.put("host", client.getHost());
          currentChildMap.put("country", client.getCountry());
          currentChildMap.put("pageURL", client.getPageURL());

          int clientFlagInt = client.getFlag();
          currentChildMap.put("flag", ovv.getResources().getDrawable(clientFlagInt));

          int clientBrowserInt = client.getBrowser();
          currentChildMap.put("browser", ovv.getResources().getDrawable(clientBrowserInt));

          String keyWords = client.getKeyWords();
          int clientRefererInt = client.getRefererIcon();

          if (!keyWords.equals("")){
             currentChildMap.put("keyWords", keyWords);
             currentChildMap.put("refererIcon", ovv.getResources().getDrawable(clientRefererInt));

          }

          childrenInvited.add(currentChildMap);
       }

       //OnChat
       if (client.getState().equals("IWCS1006S")){
          Map<String, Object> currentChildMap = new HashMap<String, Object>();

          currentChildMap.put("host", client.getHost());
          currentChildMap.put("country", client.getCountry());
          currentChildMap.put("pageURL", client.getPageURL());
       //   currentChildMap.put("keyWords", client.getReferer());

          childrenInvited.add(currentChildMap);
       }

       //Closed
       if (client.getState().equals("IWCS1007S")){
          Map<String, Object> currentChildMap = new HashMap<String, Object>();

          currentChildMap.put("host", client.getHost());
          currentChildMap.put("country", client.getCountry());
          currentChildMap.put("pageURL", client.getPageURL());
       //   currentChildMap.put("keyWords", client.getReferer());

          childrenClosed.add(currentChildMap);
       }

       if (client.getState().equals("IWCS1009S")){
          Map<String, Object> currentChildMap = new HashMap<String, Object>();

          currentChildMap.put("host", client.getHost());
          currentChildMap.put("country", client.getCountry());
          currentChildMap.put("pageURL", client.getPageURL());

          int clientFlagInt = client.getFlag();
          currentChildMap.put("flag", ovv.getResources().getDrawable(clientFlagInt));

          int clientBrowserInt = client.getBrowser();
          currentChildMap.put("browser", ovv.getResources().getDrawable(clientBrowserInt));

          String keyWords = client.getKeyWords();
          int clientRefererInt = client.getRefererIcon();

          if (!keyWords.equals("")){
             currentChildMap.put("keyWords", keyWords);
             currentChildMap.put("refererIcon", ovv.getResources().getDrawable(clientRefererInt));

          }

          childrenOffline.add(currentChildMap);
       }

    }

     childData.add(childrenOnline);
     childData.add(childrenInvited);
     childData.add(childrenClosed);
     childData.add(childrenOffline);

}


public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
     final View v = super.getChildView(groupPosition, childPosition, isLastChild, convertView, parent);

     // Populate your custom view here
     ((TextView)v.findViewById(R.id.hostname)).setText( (String) ((Map<String,Object>)getChild(groupPosition, childPosition)).get("host") );
     ((TextView)v.findViewById(R.id.country)).setText( (String) ((Map<String,Object>)getChild(groupPosition, childPosition)).get("country") );
     ((TextView)v.findViewById(R.id.pageURL)).setText( (String) ((Map<String,Object>)getChild(groupPosition, childPosition)).get("pageURL") );
     ((TextView)v.findViewById(R.id.keyWords)).setText( (String) ((Map<String,Object>)getChild(groupPosition, childPosition)).get("keyWords") );
     ((ImageView)v.findViewById(R.id.countryFlag)).setImageDrawable( (Drawable) ((Map<String,Object>)getChild(groupPosition, childPosition)).get("flag") );
     ((ImageView)v.findViewById(R.id.browserIcon)).setImageDrawable( (Drawable) ((Map<String,Object>)getChild(groupPosition, childPosition)).get("browser") );
     ((ImageView)v.findViewById(R.id.refererIcon)).setImageDrawable( (Drawable) ((Map<String,Object>)getChild(groupPosition, childPosition)).get("refererIcon") );

     return v;
}

public View newChildView(boolean isLastChild, ViewGroup parent) {
      return layoutInflater.inflate(R.layout.childrow, null, false);
}   
}

Excetion

Thread [<1> main] (Suspended (exception IllegalStateException))   
ExpandableListView(ListView).layoutChildren() line: 1662   
AbsListView$CheckForTap.run() line: 1884   
ViewRoot(Handler).handleCallback(Message) line: 587   
ViewRoot(Handler).dispatchMessage(Message) line: 92   
Looper.loop() line: 123   
ActivityThread.main(String[]) line: 4627   
Method.invokeNative(Object, Object[], Class, Class[], Class, int, boolean) line: not available [native method]   
Method.invoke(Object, Object...) line: 521   
ZygoteInit$MethodAndArgsCaller.run() line: 868   
ZygoteInit.main(String[]) line: 626   
NativeStart.main(String[]) line: not available [native method]

Can anybody help me?