android - how to disable button in listview -

i new android development , having hard time wrapping head around android listviews. pretty went through entire google search , tried every "possible" solution, without getting listview, having hard time solving problem.

i want disable particular button when click complete_btn in listview item.

right now, complete_btn.setonclicklistener in else {} part giving me null pointer exception (it's fine in if(converview == null) part). if remove code, works fine, commenting out in listener not work.

i want disable button if yes clicked in alert dialog pops when button pressed! please me this??

public view getview(final int position, view convertview, final viewgroup parent) {      view itemview;     if (convertview == null) {         itemview = layoutinflater.inflate(r.layout.activity_selected_delivery_item, parent, false);              final deliveryltem deliveryltemposition = epiceriedelivery.selecteddeliveryitem.get(position);              icon = (imageview) itemview.findviewbyid(r.id.selected_delivery_img);             name = (textview) itemview.findviewbyid(r.id.selected_item_name);             phone_tx = (textview) itemview.findviewbyid(r.id.selected_item_phone);             complete_btn = (button) itemview.findviewbyid(r.id.selected_complete_btn);              if(deliveryltemposition.order_taken_str.equals("2")){                 complete_btn.setenabled(false);             }             phone_tx.settext(deliveryltemposition.recipient_phonenum);          complete_btn.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view v) {                 ((listview) parent).performitemclick(v, position , 0);                 try{                     order_seq = deliveryltemposition.order_seq;                     position_sms = position;                     deliveryltem deliveryltemposition1 = epiceriedelivery.selecteddeliveryitem.get(position);                     string name = deliveryltemposition1.recipient_name;                     string phone = deliveryltemposition1.recipient_phonenum;                     alertdialog dialog = createdialogbox_finish(name, phone, position);                     dialog.show();                 }catch (exception e){                  }             }         });         return itemview;     }else{         itemview = convertview;         if(epiceriedelivery.selecteddeliveryitem.size() != 0){             final deliveryltem deliveryltemposition = epiceriedelivery.selecteddeliveryitem.get(position);               name = (textview) itemview.findviewbyid(r.id.selected_item_name);             phone_tx = (textview) itemview.findviewbyid(r.id.selected_item_phone);             complete_btn = (button) itemview.findviewbyid(r.id.selected_complete_btn);              if(deliveryltemposition.order_taken_str.equals("2")){                 complete_btn.setenabled(false);             }               complete_btn.setonclicklistener(new view.onclicklistener() {                 @override                 public void onclick(view v) {                     ((listview) parent).performitemclick(v, position , 0);                     try{                         order_seq = deliveryltemposition.order_seq;                         position_sms = position;                         deliveryltem deliveryltemposition1 = epiceriedelivery.selecteddeliveryitem.get(position);                         string name = deliveryltemposition1.recipient_name;                         string phone = deliveryltemposition1.recipient_phonenum;                         buttons.add(complete_btn);                         alertdialog dialog = createdialogbox_finish(name, phone, position);                         dialog.show();                     }catch (exception e){                      }                 }             });         }         return convertview;     }}    private alertdialog createdialogbox_finish(string name, string phone, int position1){      final string name_str = name;     final string phone_str = phone;     courier_id = selectedactivity2.courier_id;     int button_pos = position1;     final string message_finish = "message_content";     buttons.get(0).setenabled(false);     buttons.clear();      alertdialog.builder builder = new alertdialog.builder(getcontext());     builder.setmessage("배송을 완료하셨습니까?");     builder.setpositivebutton("yes", new dialoginterface.onclicklistener() {         @override         public void onclick(dialoginterface dialog, int which) {             try{                 smsmanager smsmanager = smsmanager.getdefault();                 if (message_finish.length() > 60) {                     arraylist<string> contents = smsmanager.dividemessage(message_finish);                     for(int j = 0; j<contents.size(); j++){                         smsmanager.sendtextmessage(phone_str, null, contents.get(j), null, null);                     }                 } else {                                       smsmanager.sendtextmessage(phone_str, null, message_finish, null, null);                 }              }catch (exception e){             }         }     });      builder.setnegativebutton("no", new dialoginterface.onclicklistener() {         @override         public void onclick(dialoginterface dialog, int which) {         }     });     alertdialog dialog = builder.create();     return dialog; } 

add

button button = dialog.getbutton(alertdialog.button_positive); button.setenabled(false); 

inside

builder.setpositivebutton("yes", new dialoginterface.onclicklistener() {           } 

method :

builder.setpositivebutton("yes", new dialoginterface.onclicklistener() {         @override         public void onclick(dialoginterface dialog, int which) {              button button = dialog.getbutton(alertdialog.button_positive);             button.setenabled(false);              try{                 smsmanager smsmanager = smsmanager.getdefault();                 if (message_finish.length() > 60) {                     arraylist<string> contents = smsmanager.dividemessage(message_finish);                     for(int j = 0; j<contents.size(); j++){                         smsmanager.sendtextmessage(phone_str, null, contents.get(j), null, null);                     }                 } else {                                       smsmanager.sendtextmessage(phone_str, null, message_finish, null, null);                 }              }catch (exception e){             }         }     });