android - Whole listview gets duplicated -

i've listview shows values web service. fine when loads listview. when click on item open new fragment (which shows details of item) , same listview, items doubles everytime. example, if have (in original) 5 items in total. when fragment, total count 10, 15 , on. means app adding items again , again. searched solution , did general solution adapter.notifydatasetchanged() still gets duplicated. if can show me problem, grateful.

public class customlistadapter extends arrayadapter<model> {        private context mcontext;      int resource;      private arraylist<model> mlistdata = new arraylist<model>();            public customlistadapter(context mcontext, int resource, arraylist<model> mlistdata) {          super(mcontext, resource, mlistdata);          this.resource = resource;          this.mcontext = mcontext;          this.mlistdata = mlistdata;      }        public void setlistdata(arraylist<model> mlistdata) {          this.mlistdata = mlistdata;          notifydatasetchanged();      }        @override      public int getcount() {          return super.getcount();      }        @override      public view getview(final int position, view convertview, final viewgroup parent) {          view v = convertview;          final viewholder holder;          if (v == null) {              holder = new viewholder();                layoutinflater inflater = ((activity) mcontext).getlayoutinflater();                v = inflater.inflate(resource, parent, false);                holder.custname = (textview) v.findviewbyid(r.id.cust_name);              holder.date = (textview) v.findviewbyid(r.id.date);              holder.staffname = (textview) v.findviewbyid(r.id.staff_name);              holder.time = (textview) v.findviewbyid(r.id.time);              holder.service = (textview) v.findviewbyid(r.id.service);              holder.refid = (textview) v.findviewbyid(r.id.refid);                  v.settag(holder);          } else {              holder = (viewholder) v.gettag();          }                  final model item = mlistdata.get(position);            holder.custname.settext(item.getcustname());          holder.date.settext(item.getdate());          holder.staffname.settext(item.getstaffname());          holder.time.settext(item.gettime());          holder.service.settext(item.getservice());          holder.refid.settext(item.getrefid());              return v;      }        class viewholder {            textview custname, date, staffname, time, service, refid;      }  }

public class listfrag extends fragment{        private swipemenulistview listview;      private customlistadapter adapter;      private cshowprogress cshowprogress;      private sqlitehandler db;      private string uid, bookingid;      private arraylist<model> arraylist = new arraylist<>();      private static final string booked_list = "http://192.168.220.13/android/showbookinglist";        @nullable      @override      public view oncreateview(layoutinflater inflater, @nullable viewgroup container, @nullable bundle savedinstancestate) {          return inflater.inflate(r.layout.listfrag, container, false);      }        @override      public void onviewcreated(view view, @nullable bundle savedinstancestate) {          super.onviewcreated(view, savedinstancestate);            listview = (swipemenulistview)view.findviewbyid(r.id.list);          db = new sqlitehandler(getactivity());          cshowprogress = cshowprogress.getinstance();                          fetchdetails();            adapter = new customlistadapter(getactivity(), r.layout.listitem, arraylist);          listview.setadapter(adapter);                        listview.setonitemclicklistener(new adapterview.onitemclicklistener() {              @override              public void onitemclick(adapterview<?> adapterview, view view, int i, long l) {                    string = arraylist.get(i).getcustname();                  string b = arraylist.get(i).getstaffname();                  string c = arraylist.get(i).getservice();                  string d = arraylist.get(i).getdate();                  string e = arraylist.get(i).gettime();                  string f = arraylist.get(i).getrefid();                  string g = arraylist.get(i).getemail();                  string h = arraylist.get(i).getservprice();                  string j = arraylist.get(i).getspeclprice();                  string k = arraylist.get(i).getstatus();                      db.adddetails(a, b, c, d, e, f, g, h, j, k);                    detailsview details = new detailsview();                  ((bookings)getactivity()).replacefragment(details);              }          });                 }        private void fetchdetails() {            cshowprogress.showprogress(getactivity());            stringrequest stringrequest = new stringrequest(request.method.post, booked_list,                  new response.listener<string>() {                      @override                      public void onresponse(string response) {                          cshowprogress.hideprogress();                            try {                              jsonarray jsonarray = new jsonarray(response);                              for(int i=0; i<jsonarray.length(); i++){                                  jsonobject obj = jsonarray.getjsonobject(i);                                  model model = new model();                                  model.setcustname(obj.getstring("customername"));                                  model.setdate(obj.getstring("staffdate"));                                  model.setstaffname(obj.getstring("staffname")+"(staff)");                                  model.settime(obj.getstring("stafftime"));                                  model.setservice(obj.getstring("servicename"));                                  model.setrefid(obj.getstring("booking_referenceid"));                                  model.setemail(obj.getstring("customeremail"));                                  model.setservprice(obj.getstring("serviceprice"));                                  model.setspeclprice(obj.getstring("specialprice"));                                  model.setstatus(obj.getstring("status"));                                  model.setbookid(obj.getstring("bookingid"));                                    arraylist.add(model);                              }                                adapter.notifydatasetchanged();                                      } catch (jsonexception e) {                              // json error                              e.printstacktrace();                              toast.maketext(getactivity(), "json error: " + e.getmessage(), toast.length_long).show();                          }                      }                  }, new response.errorlistener() {              @override              public void onerrorresponse(volleyerror error) {                  toast.maketext(getactivity(), "volleyerror" + error.tostring(), toast.length_long).show();              }          }) {              @override              protected map<string, string> getparams() {                  map<string, string> params = new hashmap<string, string>();                    params.put("spaid", "145");                  return params;              }            };            requestqueue requestqueue = volley.newrequestqueue(getactivity());          requestqueue.add(stringrequest);      }            }

try change as.. b'coz adding elements in created list.. have clear it.

 private void fetchdetails() {  if(arraylist!=null )arraylist.clear(); // line          cshowprogress.showprogress(getactivity());