android - activity A B C and startActivityForResult method -

i have 3 activities a, b , c.

a main activity. call b , c when button pressed

i have in

      @suppresswarnings("unchecked")     @override     protected void onactivityresult(int requestcode, int resultcode, intent data)     {         super.onactivityresult(requestcode, resultcode, data);  //      fragment fragment = getsupportfragmentmanager().findfragmentbyid(r.id.pager);         if(data!=null)         {             if(null!=data.getserializableextra("result"))             {                 m_calpage.updatelistview((arraylist<listtype>) data.getserializableextra("result"));             }         }         } 

b , c related onactivityresult (call rel)

  @suppresswarnings("unchecked") @override public void onactivityresult(int requestcode, int resultcode, intent data) {             if (requestcode == 1)      {         if(resultcode == -1)         {                        updatelistview((arraylist<listtype>) data.getserializableextra("result"));         }         if(resultcode==0)         {                    }     }  } 

when event occurred on b activity (e.g after press save button send data mainactivity a) rel called, , in turn onactivityresult in gets called.

now if fire event on c send data update listview in a, lose data once put in intent, not drawn on screen.

my updatelistview methods written this

public void updatelistview(arraylist<jevents>lv)     {         m_eventadapter.clear();         m_eventlst=lv;         m_eventadapter=new jlistadapter(m_context, r.id.lvevent, lv, gesturelistener);               m_lvevent.setadapter(m_eventadapter);            } 

i have 2 little issues

1. i can't call m_eventadapter.notifydatasetchanged() redraw listview, never works me, that's why have reset adapter display items. know why ?

2. please me resolve onactivityresult explained above retrieve data sent both activities b , c