android - Maintain the scroll position of a listview after getting new data -

i have listview after refreshing , getting new data. goes top of listview , not last scrolled to.

i have set timer after 2 seconds, gets new data , puts listview.

any appreciated. in advance :d

here mainactivity

@override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);      listview = (listview) findviewbyid(r.id.listview);     listview.setonitemclicklistener(this);      getjson();      handler.postdelayed(runnable, 3500); }    private runnable runnable = new runnable() {     @override     public void run() {          getjson();          handler.postdelayed(this, 2000);     } };  private void showemployee(){     jsonobject jsonobject = null;     arraylist<hashmap<string,string>> list = new arraylist<hashmap<string, string>>();     try {         jsonobject = new jsonobject(json_string);         jsonarray result = jsonobject.getjsonarray(config.tag_json_array);          for(int = 0; i<result.length(); i++){             jsonobject jo = result.getjsonobject(i);             string id = jo.getstring(config.tag_id);             string name = jo.getstring(config.tag_name);              hashmap<string,string> employees = new hashmap<>();             employees.put(config.tag_id,id);             employees.put(config.tag_name,name);             list.add(employees);         }      } catch (jsonexception e) {         e.printstacktrace();     }      listadapter adapter = new simpleadapter(             mainactivity.this, list, r.layout.list_item,             new string[]{config.tag_id,config.tag_name},             new int[]{r.id.id, r.id.name});      listview.setadapter(adapter);  }   private void getjson(){     class getjson extends asynctask<void,void,string> {         @override         protected void onpreexecute() {             super.onpreexecute();         }          @override         protected void onpostexecute(string s) {             super.onpostexecute(s);             json_string = s;             showemployee();         }         @override         protected string doinbackground(void... params) {             requesthandler rh = new requesthandler();             string s = rh.sendgetrequest(config.url_get_all);             return s;         }     }     getjson gj = new getjson();     gj.execute(); } 

in oncreate() initialize adapter empty list , bind listview. make adapter , list global in class.

now whenever add data adapter call adapter.notifydatasetchanged()

this how works in fragment.