android - how to load listview depending upon spinner data? -

here code.

mainactivity.java

protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_callplan);     // lv = getlistview();      city = (spinner) findviewbyid(r.id.city_spinner);      peoplelist = new arraylist<hashmap<string, string>>();      citylist = new arraylist<city>();      city.setonitemselectedlistener(this);      new getcity().execute();  }  private void populatespinner() {      // txtcategory.settext("");      (int = 0; < citylist.size(); i++) {         cities.add(citylist.get(i).getname());     }      // creating adapter spinner     arrayadapter<string> spinneradapter = new arrayadapter<string>(this,             android.r.layout.simple_spinner_item, cities);      // drop down layout style - list view radio button     spinneradapter             .setdropdownviewresource(android.r.layout.simple_spinner_dropdown_item);      // attaching data adapter spinner     city.setadapter(spinneradapter);  }  public void onitemselected(adapterview<?> parent, view view, int position,         long id) {     // todo auto-generated method stub      // new getcategories().execute();     spinner city1 = (spinner) parent;      if (city1.getid() == r.id.city_spinner) {          cityselected = cities.get(position);          toast.maketext(getapplicationcontext(), cityselected,                 toast.length_long).show();          new getdoctorsdetails().execute();      } else {         toast.maketext(getapplicationcontext(),                 "please select city dropdown box", toast.length_long)                 .show();     } } 

asynctask spinner data database..

private class getcity extends asynctask<void, void, void> {      @override     protected void onpreexecute() {         super.onpreexecute();         pdialog = new progressdialog(callplanactivity.this);         pdialog.setmessage("fetching cities..");         pdialog.setcancelable(false);         pdialog.show();      }      @override     protected void doinbackground(void... arg0) {         servicehandler jsonparser = new servicehandler();         string json = jsonparser.makeservicecall(url_city,                 servicehandler.get);          log.e("response: ", "> " + json);          if (json != null) {             try {                 jsonobject jsonobj = new jsonobject(json);                 if (jsonobj != null) {                     jsonarray categories = jsonobj                             .getjsonarray("doctors_details");                      (int = 0; < categories.length(); i++) {                         jsonobject catobj = (jsonobject) categories.get(i);                         city cat = new city(catobj.getstring("city"));                         citylist.add(cat);                     }                 }              } catch (jsonexception e) {                 e.printstacktrace();             }          } else {             log.e("json data", "didn't receive data server!");         }          return null;     }      @override     protected void onpostexecute(void result) {         super.onpostexecute(result);         if (pdialog.isshowing())             pdialog.dismiss();         populatespinner();     }  } 

and asynctask load listview items database based on value selected in spinner.

class getdoctorsdetails extends asynctask<string, string, jsonobject> {      jsonobject jsonobject;      @override     protected void onpreexecute() {         super.onpreexecute();      }      @override     protected jsonobject doinbackground(string... params) {         // todo auto-generated method stub          string city_name = cityselected.tostring();         list<namevaluepair> params1 = new arraylist<namevaluepair>();         params1.add(new basicnamevaluepair("city", city_name));          jsonobject = jparser.makehttprequest(url_doctors, "post", params1);         return jsonobject;      }      @override     protected void onpostexecute(jsonobject json) {         if (json != null) {             try {                 doctors_info = json.getjsonarray(tag_docdetails);                  (int = 0; < doctors_info.length(); i++) {                     jsonobject c = doctors_info.getjsonobject(i);                      string doc_name = c.getstring(tag_doc_name);                     string qualification = c.getstring(tag_doc_quali);                      hashmap<string, string> map = new hashmap<string, string>();                      map.put(tag_doc_name, doc_name);                     map.put(tag_doc_quali, qualification);                      peoplelist.add(map);                  }             } catch (jsonexception e) {                 e.printstacktrace();             }              runonuithread(new runnable() {                  @override                 public void run() {                     // todo auto-generated method stub                     listview = (listview) findviewbyid(r.id.listview);                     // pass results listviewadapter.java                     adapter = new listviewadapter(callplanactivity.this,                             peoplelist);                     // set adapter listview                     listview.setadapter(adapter);                      adapter.notifydatasetchanged();                     listview.notify();                  }               });         }          pdialog.dismiss();      }  } 

now spinner data loaded correctly , listview data loaded correctly problem when select different value spinner data in listview appended instead of updating. value both spinner data appended in 1 listview. want display different data each selection on spinner value.

thanks in advance.

in onpostexecute() method of getdoctorsdetails async task never clear peoplelist array before appending new results in it. whole onpostexecute() method executed on ui thread, there's no need of runonuithread.

what i'd first move listview = (listview) findviewbyid(r.id.listview); oncreate() method avoid searching on every spinner change.

instead of using peoplelist local array why don't add items directly adapter? start onpostexecute() adapter.clear(). add items directly adapter adapter.add() (note - depending on how you've implemented adapter might need little changes add()). lastly adapter.notifydatasetchanged() once , you're done.

also removing need of peoplelist code more readable.