Android Application closing unexpectedly while tabbed fragments swipe -

i have fragment activity contains 3 fragments 1) dayfragment 2) weekfragment 3) monthfragment when swipe first fragment application getting closed , giving exception android.support.v4.app.fragmentmanagerimpl.movetostate(fragmentmanager.java:953)

repeatremainderfragmentactivity.java fragment activity

public class repeatremainderfragmentactivity extends fragmentactivity implements         actionbar.tablistener {      private viewpager viewpager;     private tabspageradapter madapter;     private actionbar actionbar;     // tab titles     private string[] tabs = { "day", "week", "month" };      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_repeat_fragment);          // initilization         viewpager = (viewpager) findviewbyid(r.id.pager);         actionbar = getactionbar();         madapter = new tabspageradapter(getsupportfragmentmanager());          viewpager.setadapter(madapter);         actionbar.sethomebuttonenabled(true);         actionbar.setnavigationmode(actionbar.navigation_mode_tabs);                  // adding tabs         (string tab_name : tabs) {             actionbar.addtab(actionbar.newtab().settext(tab_name)                     .settablistener(this));         }          /**          * on swiping viewpager make respective tab selected          * */         viewpager.setonpagechangelistener(new viewpager.onpagechangelistener() {              @override             public void onpageselected(int position) {                 // on changing page                 // make respected tab selected                 actionbar.setselectednavigationitem(position);             }              @override             public void onpagescrolled(int arg0, float arg1, int arg2) {             }              @override             public void onpagescrollstatechanged(int arg0) {             }         });     }      @override     public void ontabreselected(tab tab, fragmenttransaction ft) {     }      @override     public void ontabselected(tab tab, fragmenttransaction ft) {         // on tab selected         // show respected fragment view         viewpager.setcurrentitem(tab.getposition());     }      @override     public void ontabunselected(tab tab, fragmenttransaction ft) {     }  } 

dayfragment.java

public class dayfragment extends fragment implements onclicklistener, onitemselectedlistener{      private view rootview;      @override     public view oncreateview(layoutinflater inflater, viewgroup container,             bundle savedinstancestate) {          rootview = inflater.inflate(r.layout.fragment_day, container, false);          initializeui();         setlisteners();         setcurrentdate();         dayrepeatspinner();          return rootview;     }      private void setcurrentdate() {         // todo auto-generated method stub              calendar c = calendar.getinstance();             simpledateformat df = new simpledateformat("dd/mm/yyyy");             string formatteddate = df.format(c.gettime());             day_startson_tv.settext(formatteddate);     }     .     .     . 

weekfragment.java

public class weekfragment extends fragment implements onclicklistener, onitemselectedlistener{      private view rootview;     @override     public view oncreateview(layoutinflater inflater, viewgroup container,             bundle savedinstancestate) {          rootview = inflater.inflate(r.layout.fragment_week, container, false);          initializeui();         setlisteners();         setcurrentdate();         weekrepeatspinner();          return rootview;     }      private void setcurrentdate() {         // todo auto-generated method stub              calendar c = calendar.getinstance();             simpledateformat df = new simpledateformat("dd/mm/yyyy");             string formatteddate = df.format(c.gettime());             week_startson_tv.settext(formatteddate);      }      private void setlisteners() {         // todo auto-generated method stub         week_startson_rl.setonclicklistener(this);         week_repeatevery_rl.setonclicklistener(this);         week_ends_rl.setonclicklistener(this);         weekspinner.setonitemselectedlistener(this);         sun_tv.setonclicklistener(this);         mon_tv.setonclicklistener(this);         tue_tv.setonclicklistener(this);         wed_tv.setonclicklistener(this);         thu_tv.setonclicklistener(this);         fri_tv.setonclicklistener(this);         sat_tv.setonclicklistener(this);     }      .     .     . 

monthfragment.java

public class monthfragment extends fragment implements onclicklistener, onitemselectedlistener{      private view rootview;      @override     public view oncreateview(layoutinflater inflater, viewgroup container,             bundle savedinstancestate) {          rootview = inflater.inflate(r.layout.fragment_month, container, false);          initializeui();         setlisteners();         setcurrentdate();         monthrepeatspinner();          return rootview;     }      private void setcurrentdate() {         // todo auto-generated method stub              calendar c = calendar.getinstance();             simpledateformat df = new simpledateformat("dd/mm/yyyy");             string formatteddate = df.format(c.gettime());             month_startson_tv.settext(formatteddate);// showing exception inthis line      }      private void setlisteners() {         // todo auto-generated method stub         month_startson_rl.setonclicklistener(this);         month_repeatevery_rl.setonclicklistener(this);         month_repearby_rl.setonclicklistener(this);         month_ends_rl.setonclicklistener(this);         monthspinner.setonitemselectedlistener(this);     }  private void initializeui() {   // todo auto-generated method stub     month_startson_rl = (relativelayout) rootview.findviewbyid(r.id.month_starton_relativelayout);     month_repeatevery_rl = (relativelayout) rootview.findviewbyid(r.id.month_repeat_relativelayout);     month_repearby_rl = (relativelayout) rootview.findviewbyid(r.id.month_repeatby_relativelayout);     month_ends_rl = (relativelayout) rootview.findviewbyid(r.id.month_ends_relativelayout);      monthspinner = (spinner) rootview.findviewbyid(r.id.month_spinner);  } 

following logcat

04-29 02:27:14.366: e/androidruntime(1499): fatal exception: main 04-29 02:27:14.366: e/androidruntime(1499): process: com.ielts.notes, pid: 1499 04-29 02:27:14.366: e/androidruntime(1499): java.lang.nullpointerexception 04-29 02:27:14.366: e/androidruntime(1499):     @ com.ielts.notes.tabswipe.monthfragment.setcurrentdate(monthfragment.java:54) 04-29 02:27:14.366: e/androidruntime(1499):     @ com.ielts.notes.tabswipe.monthfragment.oncreateview(monthfragment.java:42) 04-29 02:27:14.366: e/androidruntime(1499):     @ android.support.v4.app.fragment.performcreateview(fragment.java:1786) 04-29 02:27:14.366: e/androidruntime(1499):     @ android.support.v4.app.fragmentmanagerimpl.movetostate(fragmentmanager.java:953) 04-29 02:27:14.366: e/androidruntime(1499):     @ android.support.v4.app.fragmentmanagerimpl.movetostate(fragmentmanager.java:1136) 04-29 02:27:14.366: e/androidruntime(1499):     @ android.support.v4.app.backstackrecord.run(backstackrecord.java:739) 04-29 02:27:14.366: e/androidruntime(1499):     @ android.support.v4.app.fragmentmanagerimpl.execpendingactions(fragmentmanager.java:1499) 04-29 02:27:14.366: e/androidruntime(1499):     @ android.support.v4.app.fragmentmanagerimpl.executependingtransactions(fragmentmanager.java:488) 04-29 02:27:14.366: e/androidruntime(1499):     @ android.support.v4.app.fragmentpageradapter.finishupdate(fragmentpageradapter.java:141) 04-29 02:27:14.366: e/androidruntime(1499):     @ android.support.v4.view.viewpager.populate(viewpager.java:1073) 04-29 02:27:14.366: e/androidruntime(1499):     @ android.support.v4.view.viewpager.populate(viewpager.java:919) 04-29 02:27:14.366: e/androidruntime(1499):     @ android.support.v4.view.viewpager$3.run(viewpager.java:249) 04-29 02:27:14.366: e/androidruntime(1499):     @ android.view.choreographer$callbackrecord.run(choreographer.java:761) 04-29 02:27:14.366: e/androidruntime(1499):     @ android.view.choreographer.docallbacks(choreographer.java:574) 04-29 02:27:14.366: e/androidruntime(1499):     @ android.view.choreographer.doframe(choreographer.java:543) 04-29 02:27:14.366: e/androidruntime(1499):     @ android.view.choreographer$framedisplayeventreceiver.run(choreographer.java:747) 04-29 02:27:14.366: e/androidruntime(1499):     @ android.os.handler.handlecallback(handler.java:733) 04-29 02:27:14.366: e/androidruntime(1499):     @ android.os.handler.dispatchmessage(handler.java:95) 04-29 02:27:14.366: e/androidruntime(1499):     @ android.os.looper.loop(looper.java:136) 04-29 02:27:14.366: e/androidruntime(1499):     @ android.app.activitythread.main(activitythread.java:5017) 04-29 02:27:14.366: e/androidruntime(1499):     @ java.lang.reflect.method.invokenative(native method) 04-29 02:27:14.366: e/androidruntime(1499):     @ java.lang.reflect.method.invoke(method.java:515) 04-29 02:27:14.366: e/androidruntime(1499):     @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:779) 04-29 02:27:14.366: e/androidruntime(1499):     @ com.android.internal.os.zygoteinit.main(zygoteinit.java:595) 04-29 02:27:14.366: e/androidruntime(1499):     @ dalvik.system.nativestart.main(native method) 

where month_startson_tv defined? think error like

textview month_startson_tv = (textview)findviewbyid(r.id.month_startson_tv); 

is missing, because error message null element, , when textview not defined null , can't set text. use everywhere, should initialize @ top private view rootview; private textview month_startson_tv;