android - Unable to set relativelayout to invisible when activity starts gives NullPointerException -

i have layout have switch , relativelayout contains 2 image buttons. default switch remains in off state. want when activity loads want set relative layout b invisible , if switch set in on state relativelayout should visible.

when try set invisible in oncreate giving me nullpointerexception..

how can set layout b invisible when activity starts , if switch checked layout should visible.. ? please help..

layout.xml :-

 <switch     android:layout_width="wrap_content"     android:layout_height="wrap_content"     style="@style/btnstylebeige"     android:id="@+id/switch1"     android:layout_marginright="10dp"     android:layout_aligntop="@+id/textview7"     android:layout_alignstart="@+id/button5" />  <relativelayout     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:id="@+id/relative2"     android:layout_margintop="40dp"     android:layout_below="@+id/switch1"     android:layout_alignparentstart="true"     android:layout_alignend="@+id/taskname">      <imagebutton         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:id="@+id/pickdate"         android:src="@drawable/c2"         style="@style/btnstylebeige"         android:layout_marginstart="65dp"         android:layout_alignparenttop="true"         android:layout_alignparentstart="true" />      <imagebutton         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:id="@+id/picktime"         style="@style/btnstylebeige"         android:src="@drawable/c1"         android:layout_marginend="65dp"         android:layout_alignparenttop="true"         android:layout_alignparentend="true" />  </relativelayout> 

activity :-

@override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.addtask);      getactionbar().setdisplayhomeasupenabled(true);       relativelayout2.setvisibility(view.invisible);      switch aswitch = (switch) findviewbyid(r.id.switch1);      aswitch.setoncheckedchangelistener(this);      init();      /** capture our view elements */     //pdisplaydate = (textview) findviewbyid(r.id.displaydate);     ppickdate = (imagebutton) findviewbyid(r.id.pickdate);      /** listener click event of button */     ppickdate.setonclicklistener(new view.onclicklistener() {         public void onclick(view v) {             showdialog(date_dialog_id);         }     });     /** capture our view elements */     //pdisplaytime = (textview) findviewbyid(r.id.displaytime);     ppicktime = (imagebutton) findviewbyid(r.id.picktime);       /** listener click event of button */     ppicktime.setonclicklistener(new view.onclicklistener() {         public void onclick(view v) {             showdialog(time_dialog_id);         }     });      /** current date , time */     final calendar cal = calendar.getinstance();     pyear = cal.get(calendar.year);     pmonth = cal.get(calendar.month);      pday = cal.get(calendar.day_of_month);      mhour = cal.get(calendar.hour_of_day);     mminute = cal.get(calendar.minute); } @override public void oncheckedchanged(compoundbutton buttonview, boolean ischecked) {      relativelayout2 = (relativelayout)findviewbyid(r.id.relative2);     if(ischecked) {         relativelayout2.setvisibility(view.gone);     } else {         relativelayout2.setvisibility(view.visible);     } } 

you did not created reference of relative layout.

before line..

relativelayout2.setvisibility(view.invisible); 

add 1

relativelayout relativelayout2 = (relativelayout) findviewbyid(r.id.relative2);