android - Getting null pointer exception on interface -

i wanna pass arraylist on class class extends listfragments.but whenever call getting null pointer exception.

async class

public class searchjobasync extends asynctask<string, string, string> {     private string response;     context c;     searchmodel data;     arraylist<searchmodel> values;     getarraylist list;       public interface getarraylist {         public void getlist(arraylist<searchmodel> data);      }      public searchjobasync(context c, arraylist<searchmodel> values, getarraylist list) {         this.c = c;         this.values = values;         this.list = list;     }      public searchjobasync(context c) {         this.c = c;     }      @override     protected void onpreexecute() {         super.onpreexecute ();         commonfunctions.showprogress (c, "please wait...", true);      }      @override     protected void onpostexecute(string s) {         values = new arraylist<searchmodel> ();          super.onpostexecute (s);         if (!s.trim ().contains ("table")) {             crouton.maketext ((android.app.activity) c, "nothing found", style.info).show ();         } else {             try {                  jsonobject jsonobject = new jsonobject (s);                 jsonobject newdataset = jsonobject.getjsonobject ("newdataset");                 if (newdataset.get ("table") instanceof jsonobject) {                     jsonobject table = newdataset.getjsonobject ("table");                     data = new searchmodel (table.getstring ("job_category"), table.getstring ("min_exp"), table.getstring ("max_exp"), table.getstring ("posted_on"), table.getstring ("candidate_counts"), table.getstring ("applications"), table.getstring ("no_of_pos"), table.getstring ("job_desc"), table.getstring ("job_type"), table.getstring ("job_hours"), table.getstring ("job_status"), table.getstring ("job_exp_date"), table.getstring ("address"), table.getstring ("gender_name"), table.getstring ("religion_name"), table.getstring ("exp_summary"), table.getstring ("ijob_request_id"), table.getstring ("requestor_name"));                     values.add (data);                 } else if (newdataset.get ("table") instanceof jsonarray) {                     jsonarray tablearray = newdataset.getjsonarray ("table");                      (int = 0; < tablearray.length (); i++) {                         jsonobject table = tablearray.getjsonobject (i);                         data = new searchmodel (table.getstring ("job_category"), table.getstring ("min_exp"), table.getstring ("max_exp"), table.getstring ("posted_on"), table.getstring ("candidate_counts"), table.getstring ("applications"), table.getstring ("no_of_pos"), table.getstring ("job_desc"), table.getstring ("job_type"), table.getstring ("job_hours"), table.getstring ("job_status"), table.getstring ("job_exp_date"), table.getstring ("address"), table.getstring ("gender_name"), table.getstring ("religion_name"), table.getstring ("exp_summary"), table.getstring ("ijob_request_id"), table.getstring ("requestor_name"));                         values.add (data);                      }                  }                 if (values.size () > 0) {                     list.getlist (values);                 }              } catch (jsonexception e) {                 e.printstacktrace ();             }         }           commonfunctions.showprogress (c, "", false);         intent = new intent (c, searchjoblistactivity.class);         c.startactivity (i);     }      @override     protected string doinbackground(string... s) {         response = httprequest.post ("https://beta135.hamarisuraksha.com/web/webservice/hsjobservice.asmx/findjobforvendor").send ("vendor_ientity_code=" + "34588a34-e969-4723-84fe-e5409b66a5b7" + "&job_code=" + "&job_category=1" + "&exp_years_from=0" + "&exp_months_from=0" + "&exp_years_to=0" + "&exp_months_to=0").body ();         response = response.replaceall ("<[^>]*>", "").replaceall ("\n", "");         log.e ("search jobs", "" + response);         return response;     }   } 

listfragment class

public class searchjoblist extends listfragment implements searchjobasync.getarraylist {     private view view;     private listview lvsearchjobs;     private arraylist<searchmodel> data;     searchjobcustomlist customlist;     searchjobasync searchjobasync;     private context c;      @override     public view oncreateview(layoutinflater inflater, viewgroup container, bundle savedinstancestate) {         view = inflater.inflate (r.layout.search_job_lists, container, false);         return view;     }      @override     public void onactivitycreated(bundle savedinstancestate) {         super.onactivitycreated (savedinstancestate);         c = getactivity ();         lvsearchjobs = (listview) getactivity ().findviewbyid (android.r.id.list);         data = new arraylist<searchmodel> ();         searchjobasync.execute ();         searchjobasync = new searchjobasync (c, data, this);       }      @override     public void getlist(arraylist<searchmodel> data) {         customlist = new searchjobcustomlist (c, data);         setlistadapter (customlist);     } } 

i m getting error on lines said logcat

list.getlist (values); 

and

public class searchjobasync extends asynctask<string, string, string> 

logcat

06-26 13:03:46.256  31713-31713/com.jobs_on_call_fragments e/androidruntime﹕ fatal exception: main     java.lang.nullpointerexception             @ com.jobs_on_call_fragments.asynctasks.searchjobasync.onpostexecute(searchjobasync.java:83)             @ com.jobs_on_call_fragments.asynctasks.searchjobasync.onpostexecute(searchjobasync.java:25)             @ android.os.asynctask.finish(asynctask.java:631)             @ android.os.asynctask.access$600(asynctask.java:177)             @ android.os.asynctask$internalhandler.handlemessage(asynctask.java:644)             @ android.os.handler.dispatchmessage(handler.java:99)             @ android.os.looper.loop(looper.java:213)             @ android.app.activitythread.main(activitythread.java:4787)             @ java.lang.reflect.method.invokenative(native method)             @ java.lang.reflect.method.invoke(method.java:511)             @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:789)             @ com.android.internal.os.zygoteinit.main(zygoteinit.java:556)             @ dalvik.system.nativestart.main(native method) 

other activity uses async

public class searchjobsfragment extends fragment implements view.onclicklistener {      private view view;     private spinner spcategory;     private button btsearch;     private spinner sptoyrs;     private spinner spfrommonths;     private spinner spfromyrs;     private spinner sptomonths;     private edittext etjobcode;     private string[] yrsarray, montharray, professionarray;     private arrayadapter<string> toyrs, tomonths, profession;     private context c;      @override     public view oncreateview(layoutinflater inflater, viewgroup container, bundle savedinstancestate) {         view = inflater.inflate (r.layout.search_jobs_frag, container, false);         return view;     }      private void initialize() {          c = getactivity ();         spcategory = (spinner) getactivity ().findviewbyid (r.id.sp_category);         btsearch = (button) getactivity ().findviewbyid (r.id.bt_search);         sptoyrs = (spinner) getactivity ().findviewbyid (r.id.sp_to_yrs);         spfrommonths = (spinner) getactivity ().findviewbyid (r.id.sp_from_months);         spfromyrs = (spinner) getactivity ().findviewbyid (r.id.sp_from_yrs);         sptomonths = (spinner) getactivity ().findviewbyid (r.id.sp_to_months);         etjobcode = (edittext) getactivity ().findviewbyid (r.id.et_job_code);         btsearch.setonclicklistener (this);     }      @override     public void onactivitycreated(bundle savedinstancestate) {         super.onactivitycreated (savedinstancestate);         initialize ();         spinnersetup ();     }      private void spinnersetup() {          //for to/from yrs          yrsarray = getresources ().getstringarray (r.array.experience_yrss);         toyrs = new arrayadapter<string> (c, r.layout.spinner_textview, yrsarray);         toyrs.setdropdownviewresource (android.r.layout.simple_list_item_single_choice);         sptoyrs.setadapter (toyrs);         spfromyrs.setadapter (toyrs);           // to/from months         montharray = getresources ().getstringarray (r.array.experience_months);         tomonths = new arrayadapter<string> (c, r.layout.spinner_textview, montharray);         tomonths.setdropdownviewresource (android.r.layout.simple_list_item_single_choice);         sptomonths.setadapter (tomonths);         spfrommonths.setadapter (tomonths);           //for category          professionarray = getresources ().getstringarray (r.array.profession);         arrays.sort (professionarray, 1, professionarray.length);         profession = new arrayadapter<string> (c, r.layout.spinner_textview, professionarray);         profession.setdropdownviewresource (android.r.layout.simple_list_item_single_choice);         spcategory.setadapter (profession);       }      @override     public void onclick(view view) {         searchjobasync searchjobasync = new searchjobasync (c);         searchjobasync.execute ();     } } 

problem:

implements searchjobasync.getarraylist 

you trying call interface on different class not static, thats why compiler having trouble find it

solution:

make getarraylist static interface

static interface getarraylist {         public void getlist(arraylist<searchmodel> data);      } 

edit:

if called other activity call null pointer check

sample:

if (values.size () > 0) {             if(list != null)                 list.getlist (values);             }