android - How to get all values from text view of custom list view -

i want values of text view list view. how can it. have list view , put array list in list view. list view custom list view. want data price text view , want show total of price . , code give error
it's code.

public class selectedproductfromshopingcartshow extends appcompatactivity {      arraylist<showproducts> arraylist = new arraylist<>();     string condition = "selecteditemsfromshoppingcart";     customadapter customadapter;     listview listview;     textview tvtotal;     int total;     private static final string tag = "selectedproductfromshop";      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_selected_product_from_shoping_cart_show);         listview = (listview) findviewbyid(r.id.listviewselecteditemsofshopingcart);         tvtotal = (textview) findviewbyid(r.id.tvtotal);          arraylist = (arraylist<showproducts>) getintent().getserializableextra("selectedlist");          customadapter = new customadapter(selectedproductfromshopingcartshow.this, r.layout.show_selected_item_of_shopingcart, condition, arraylist);         listview.setadapter(customadapter);         total = gettotal(listview);         tvtotal.settext(string.valueof(total).tostring());     }      public int gettotal(listview listview) {         int sum = 0;         (int = 0; < listview.getcount(); i++) {             log.d(tag, "gettotal: "+listview.getcount());             log.d(tag, "gettotal: "+arraylist.size());             view view = listview.getchildat(i);             textview tvprice = (textview) view.findviewbyid(r.id.tvsetpriceofseleteditem);             textview tvquantity = (textview) view.findviewbyid(r.id.tvqunatitysetofselecteditem);              int price = integer.parseint(tvprice.gettext().tostring());             int quantity = integer.parseint(tvquantity.gettext().tostring());             sum = sum + price * quantity;         }         return sum;      } } 

and it's error. don't know how can it. please me.

07-26 18:03:49.404 21155-21155/com.sizdom.sizdomstockmanager e/androidruntime: fatal exception: main                                                                                java.lang.runtimeexception: unable start activity componentinfo{com.sizdom.sizdomstockmanager/com.sizdom.sizdomstockmanager.selectedproductfromshopingcartshow}: java.lang.nullpointerexception                                                                                    @ android.app.activitythread.performlaunchactivity(activitythread.java:2204)                                                                                    @ android.app.activitythread.handlelaunchactivity(activitythread.java:2254)                                                                                    @ android.app.activitythread.access$600(activitythread.java:141)                                                                                    @ android.app.activitythread$h.handlemessage(activitythread.java:1234)                                                                                    @ android.os.handler.dispatchmessage(handler.java:99)                                                                                    @ android.os.looper.loop(looper.java:137)                                                                                    @ android.app.activitythread.main(activitythread.java:5069)                                                                                    @ java.lang.reflect.method.invokenative(native method)                                                                                    @ java.lang.reflect.method.invoke(method.java:511)                                                                                    @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:793)                                                                                    @ com.android.internal.os.zygoteinit.main(zygoteinit.java:560)                                                                                    @ dalvik.system.nativestart.main(native method)                                                                                 caused by: java.lang.nullpointerexception                                                                                    @ com.sizdom.sizdomstockmanager.selectedproductfromshopingcartshow.gettotal(selectedproductfromshopingcartshow.java:88)                                                                                    @ com.sizdom.sizdomstockmanager.selectedproductfromshopingcartshow.oncreate(selectedproductfromshopingcartshow.java:38)                                                                                    @ android.app.activity.performcreate(activity.java:5104)                                                                                    @ android.app.instrumentation.callactivityoncreate(instrumentation.java:1092)                                                                                    @ android.app.activitythread.performlaunchactivity(activitythread.java:2148)                                                                                    @ android.app.activitythread.handlelaunchactivity(activitythread.java:2254)                                                                                     @ android.app.activitythread.access$600(activitythread.java:141)                                                                                     @ android.app.activitythread$h.handlemessage(activitythread.java:1234)                                                                                     @ android.os.handler.dispatchmessage(handler.java:99)                                                                                     @ android.os.looper.loop(looper.java:137)                                                                                     @ android.app.activitythread.main(activitythread.java:5069)                                                                                     @ java.lang.reflect.method.invokenative(native method)                                                                                     @ java.lang.reflect.method.invoke(method.java:511)                                                                                     @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:793)                                                                                     @ com.android.internal.os.zygoteinit.main(zygoteinit.java:560)                                                                                     @ dalvik.system.nativestart.main(native method)  

i check out multiple sites solutions. don't find soluotion

custom adapter

public class customadapter extends arrayadapter {     private list<integer> list;     private list<showproducts> listshowproducts;     private context context;     private int resource;     private string condition;     string uri;     private static final string tag = "customadapter";     int = 0;      public customadapter(@nonnull context context, @layoutres int resource, list<showproducts> objects) {         super(context, resource, objects);         this.context = context;         this.resource = resource;         this.listshowproducts = objects;     }      @override     public int getcount() {         return super.getcount();     }      @nullable     @override     public object getitem(int position) {         return super.getitem(position);     }      @nonnull     @override     public view getview(int position, @nullable view convertview, @nonnull viewgroup parent) {          view view = layoutinflater.from(context).inflate(resource, parent, false);                final showproducts showproducts = listshowproducts.get(position);              imageview imageview = (imageview) view.findviewbyid(r.id.imageviewofselecteditem);             imageview plus = (imageview) view.findviewbyid(r.id.imageviewplus);             imageview minus = (imageview) view.findviewbyid(r.id.imageviewminus);             textview tvsetnameofseleteditem = (textview) view.findviewbyid(r.id.tvsetnameofseleteditem);             textview tvsetsizeofseleteditem = (textview) view.findviewbyid(r.id.tvsetsizeofseleteditem);             textview tvsetpriceofseleteditem = (textview) view.findviewbyid(r.id.tvsetpriceofseleteditem);             final textview tvqunatitysetofselecteditem = (textview) view.findviewbyid(r.id.tvqunatitysetofselecteditem);            tvsetnameofseleteditem.settext(showproducts.getproduct_name().tostring());             tvsetsizeofseleteditem.settext(showproducts.getsize_name());             tvsetpriceofseleteditem.settext(string.valueof(showproducts.getsize_price()).tostring());             uri = showproducts.getproduct_photo().tostring();              picasso.with(context).load(uri).into(imageview);              plus.setonclicklistener(new view.onclicklistener() {                 @override                 public void onclick(view v) {                     int a=integer.parseint(tvqunatitysetofselecteditem.gettext().tostring());                     a++;                     if (a<=showproducts.getsize_quantity())                     tvqunatitysetofselecteditem.settext(string.valueof(a).tostring());                 }             });              minus.setonclicklistener(new view.onclicklistener() {                 @override                 public void onclick(view v) {                     int a=integer.parseint(tvqunatitysetofselecteditem.gettext().tostring());                     a--;                     if (a>0)                     tvqunatitysetofselecteditem.settext(string.valueof(a).tostring());                 }             });         }         return view;     } } 

it's list view show value when value arror

i debug app

 public int gettotal(listview listview) {         int sum = 0;         (int = 0; < listview.getcount(); i++) { // i=0;             log.d(tag, "gettotal: "+listview.getcount());              log.d(tag, "gettotal: "+arraylist.size()); // arraylist=4;             view view = listview.getchildat(i); //view=null;             textview tvprice = (textview) view.findviewbyid(r.id.tvsetpriceofseleteditem);             log.d(tag, "gettotal: "+tvprice.gettext());             textview tvquantity = (textview) view.findviewbyid(r.id.tvqunatitysetofselecteditem); 

you not setting price in tvprice , quantity in tvquantity textview. null value.