android - Not adding items to list with SharedPreferences? -

i'm trying make app can add item list using edittext , listview. has remember added list because there multiple activities, i'm using sharedpreferences. first time activity opened crashed because looked 1 of sharedpreferences files wasn't there, added

if (newquestion == null) {         return;     } 

but never adds list.

my full code activity:

package com.example.dogwise;  import android.content.intent; import android.support.v7.app.appcompatactivity; import android.os.bundle; import android.view.view; import java.util.arraylist; import java.util.arrays; import java.util.list; import android.widget.arrayadapter; import android.widget.listview; import android.widget.adapterview; import android.content.sharedpreferences;  public class questions extends appcompatactivity {     listview listview;     string[] listelements = new string[]{             "how food should feed dog?",             "how teach dog sit?"     };      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_questions);          listview = (listview) findviewbyid(r.id.questionslist);          final list<string> listelementsarraylist = new arraylist<string>(arrays.aslist(listelements));         final arrayadapter<string> adapter = new arrayadapter<string>                 (questions.this, android.r.layout.simple_list_item_1, listelementsarraylist);         listview.setadapter(adapter);         adapter.notifydatasetchanged();          sharedpreferences pref = getapplicationcontext().getsharedpreferences("mypref", mode_private);         string newquestion=pref.getstring("key_question", null);          if (newquestion == null) {             return;         }          listelementsarraylist.add(newquestion);         adapter.notifydatasetchanged();          bundle newquestion = getintent().getextras();         if (newquestion == null) {             return;         }         final string questionname = newquestion.getstring("questionname");          listelementsarraylist.add(questionname);         adapter.notifydatasetchanged();          sharedpreferences.editor editor = getsharedpreferences("mypref", mode_private).edit();         editor.putstring("key_question", questionname);          editor.apply();          listview.setonitemclicklistener(new adapterview.onitemclicklistener() {             public void onitemclick(adapterview<?> parent, view view,                                     int position, long id) {                 if (position == 0) {                     intent myintent = new intent(view.getcontext(), question_1.class);                     startactivityforresult(myintent, 0);                 }                  if (position == 1) {                     intent myintent = new intent(view.getcontext(), question_2.class);                     startactivityforresult(myintent, 0 );                 }                  if (position == 2) {                     intent myintent = new intent(view.getcontext(), question_asked.class);                     myintent.putextra("questiontitle", questionname);                     startactivityforresult(myintent, 0);                 }             }         });     }      ;      public void backhomeonclick(view view) {         intent b = new intent(this, homescreen.class);         startactivity(b);     }      public void askaquestiononclick(view view) {         intent = new intent(this, askaquestion.class);         startactivity(i);     }      ; } 

you publishing data intent using key= "questiontitle" trying retrieve using key= "questionname".