java - ListView getting populated with the same data twice? -

i have list view displays data based on text change.however same data displayed twice.for example if list contains single 'apple' list contain 2 apple's. i.e. same entry twice.

this code :-

 private void showdocno(string response) {     parseadvopen pao = new parseadvopen(response);     pao.parsejson();     list<map<string, string>> dn_info = new arraylist<map<string, string>>();     map<string, string> dn_map;     int counts = parseadvopen.adv_no.length;     (int = 0; < counts; ++i) {         dn_map = new hashmap<>();         dn_map.put("doc_no", parseadvopen.adv_no[i]);         dn_map.put("date", parseadvopen.date[i]);         dn_map.put("cust_name", parseadvopen.cust_name[i]);         dn_map.put("cust_number", parseadvopen.cust_number[i]);         dn_map.put("item_count", parseadvopen.item_count[i]);         dn_map.put("total", parseadvopen.sum_total[i]);         dn_map.put("paid", parseadvopen.paid[i]);         dn_info.add(dn_map);     }      dnadapter = new simpleadapter(getactivity().getapplicationcontext(), dn_info, r.layout.list_docno, new string[]{"doc_no", "cust_name", "cust_number"}, new int[]{r.id.textviewdn, r.id.customer_name, r.id.customer_mobile});     doc_list.setadapter(dnadapter);     log.d("dninfo", dn_info.tostring());      inputsearch.addtextchangedlistener(new textwatcher() {         @override         public void beforetextchanged(charsequence s, int start, int count, int after) {              doc_list.setvisibility(view.invisible);             advopen_list.setvisibility(view.visible);             searchlayout.setvisibility(view.gone);          }          @override         public void ontextchanged(charsequence s, int start, int before, int count) {              doc_list.setvisibility(view.visible);         }          @override         public void aftertextchanged(editable s) {             if (s.length() == 0) {                 doc_list.setvisibility(view.invisible);             } else {                 dnadapter.getfilter().filter(s);                 doc_list.setvisibility(view.visible);              }          }     });      doc_list.setonitemclicklistener(new adapterview.onitemclicklistener() {         @override         public void onitemclick(adapterview<?> parent, view view, int position, long id) {             map docselected = (map) dnadapter.getitem(position);             string doc_number = (string) docselected.get("doc_no");             string date = (string) docselected.get("date");             string customername = (string) docselected.get("cust_name");             string mobileno = (string) docselected.get("cust_number");             string icount = (string) docselected.get("item_count");             string total = (string) docselected.get("total");             string paid = (string) docselected.get("paid");               log.d("document selected", doc_number + " " + customername + " " + mobileno + " " + date);             advopen_list.setvisibility(view.gone);             doc_list.setvisibility(view.gone);             searchlayout.setvisibility(view.visible);             tv_docno.settext(doc_number);             tv_date.settext(date);             tv_name.settext(customername);             tv_mobile.settext(mobileno);             tv_itemcount.settext(icount);             tv_tot.settext(total);             tv_paid.settext(paid);           }     });   } 

this method gets called on response of volley request mysql database.

any or suggestion appreciated.thank you.