Android :: How To Refresh Updated Contacts In List View Using Base Adapter?

Currently I am working on IM, and I am facing problem during implementations. I am implementing this messenger using XMPP client and using smack API for implementing all features like contacts list, online offline status, and chat also. Prblem which I am facing:

Its my list view where I am showing contacts list
public class ContactsList extends ListActivity implements OnClickListener{
@Override protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ContactsManager manager = new ContactsManager(this); setListAdapter(manager);
} public class ContactsManager extends BaseAdapter{
private LayoutInflater mInflater; private Bitmap mainListIcons[];
private static ContactsInfo contactsInfo; public ContactsManager(Context context) {
mInflater = LayoutInflater.from(context); mainListIcons= new Bitmap[3];
mainListIcons[0] = BitmapFactory.decodeResource (context.getResources(), R.drawable.online);
mainListIcons[1] = BitmapFactory.decodeResource (context.getResources(), R.drawable.offline);
} @Override public int getCount() { return Global.contacts.size();//
contacts is vector where I am saving my contacts
} public Object getItem(int position) { return position;
} public long getItemId(int position) { return position;
} public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder; if (convertView == null) {
convertView = mInflater.inflate (R.layout.main_settings_lists_icon_text, null);
holder = new ViewHolder(); holder.mainListDisplayText = (TextView) convertView.findViewById(R.id.main_settings_lists_text);
holder.mainListDisplayIcon = (ImageView) convertView.findViewById(R.id.main_settings_lists_icon);
convertView.setTag(holder);}else{ holder = (ViewHolder) convertView.getTag();
} contactsInfo = (ContactsInfo)Global.contacts.elementAt (position);
String username = contactsInfo.getUsername(); String status = contactsInfo.getUserstatus();
if(status.equalsIgnoreCase("unavailable")) { older.mainListDisplayIcon.setImageBitmap(mainListIcons[1]);
}else{ holder.mainListDisplayIcon.setImageBitmap(mainListIcons[0]);
} holder.mainListDisplayText.setText(username); return convertView;
} static class ViewHolder { TextView mainListDisplayText;
ImageView mainListDisplayIcon;}
public class ContactsHandler implements RosterListener {
@Override public void entriesAdded(Collection<String> c) {
for(String s:c) { Log.i("ADDED Contacts",s);
} } @Override public void presenceChanged(Presence p) {
Log.i("PRESENCE",p.getFrom()); Log.i("IS Available",""+p.isAvailable());
Log.i("UserStatus",""+p.getStatus()); if(p.getFrom().contains("@") && p.isAvailable())
{ ChatManager chatmanager = Connection.getVopConnection getXMPPConnection().getChatManager();
Chat newChat = chatmanager.createChat("gulfam@imran-mehmood", new ChatHandler());
} } }