Android Listview - Null Pointer Exception -

when trying display items on listview showing nullpointerexception. in think got null either position or convertview , textview id , linearlayout id both correct. below lines got exception in code.

viewitem.ll.setbackgroundcolor(rainbow[position]); viewitem.time.settext(timevalueslist.get(position).getelapsetime().replace(" minutes", "")); 

here mycode :

       class timerlistadapter extends baseadapter{          layoutinflater li;         context ct;         public timerlistadapter(context c){             this.ct=c;         }         @override         public int getcount() {             // todo auto-generated method stub             return timevalueslist.size();         }          @override         public object getitem(int position) {             // todo auto-generated method stub             return position;         }          @override         public long getitemid(int position) {             // todo auto-generated method stub             return position;         }          @override         public view getview(final int position, view convertview, viewgroup arg2) {             li=(layoutinflater)ct.getsystemservice(layout_inflater_service);             final viewitem viewitem;             if (convertview == null) {               viewitem = new viewitem();               convertview=li.inflate(r.layout.salontimer_listitem, null);               viewitem.time=(textview)convertview.findviewbyid(r.id.elapse_time);               viewitem.ll=(linearlayout)convertview.findviewbyid(r.id.llayout);               viewitem.playnpause=(imageview)convertview.findviewbyid(r.id.play_pause_time);               viewitem.addtime=(imageview)convertview.findviewbyid(r.id.add_time);               viewitem.deletetime=(imageview)convertview.findviewbyid(r.id.delete_time);               viewitem.sharetime=(imageview)convertview.findviewbyid(r.id.share_time);             }else{                 viewitem = (viewitem) convertview.gettag();             }             int[] rainbow = context.getresources().getintarray(r.array.rainbow);             viewitem.ll.setbackgroundcolor(rainbow[position]);             viewitem.time.settext(timevalueslist.get(position).getelapsetime().replace(" minutes", ""));             viewitem.playnpause.setonclicklistener(new onclicklistener() {                  @override                 public void onclick(view v) {                     settime(viewitem.time,viewitem.time.gettag().tostring(),integer.parseint(timevalueslist.get(position).getelapsetime().replace(" minutes", ""))*60*1000);                 }             });             viewitem.addtime.setonclicklistener(new onclicklistener() {                  @override                 public void onclick(view v) {                  }             });             viewitem.deletetime.setonclicklistener(new onclicklistener() {                  @override                 public void onclick(view v) {                     sdb.deletesalontime(timevalueslist.get(position).getid());                     timevalueslist.remove(position);                     tadapter.notifydatasetchanged();                 }             });             viewitem.sharetime.setonclicklistener(new onclicklistener() {                  @override                 public void onclick(view v) {                  }             });              return convertview;         }         protected void settime(final textview tv, string tag,int time) {              if (tv.gettag().tostring().equals(tag)) {                  countdowntimer ct = new countdowntimer(time, 1000)                    { //the timer runs 30 seconds in case                      public void ontick(long millisuntilfinished){                          int seconds = (int) ((millisuntilfinished) / 1000) % 60 ;                          int minutes = (int) (((millisuntilfinished ) / (1000*60)) % 60);                           string min = integer.tostring(minutes);                          string sec = integer.tostring(seconds);                          tv.settext(min+":"+sec);                      }                      @override                     public void onfinish() {                       }                   }.start();                 }         }      } 

if convertview not null, retreive viewitem tag. have never set tag before.

to fix add line @ end if (convertview == null) block:

convertview.settag(viewitem);