update

lib/pages/discount/discount_list_row.dart

@@ -5,15 +5,14 @@ import 'package:fcs/pages/discount/discount_editor.dart';
 import 'package:fcs/pages/main/util.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
-import 'package:flutter_icons/flutter_icons.dart';
 import 'package:intl/intl.dart';
 
 typedef OnSelect(Discount discount);
 
 class DiscountListRow extends StatelessWidget {
-  final OnSelect onSelect;
-  final Discount discount;
-  DiscountListRow({Key key, this.discount, this.onSelect}) : super(key: key);
+  final OnSelect? onSelect;
+  final Discount? discount;
+  DiscountListRow({Key? key, this.discount, this.onSelect}) : super(key: key);
 
   final DateFormat dateFormat = new DateFormat("dd MMM yyyy");
 
@@ -21,8 +20,8 @@ class DiscountListRow extends StatelessWidget {
   Widget build(BuildContext context) {
     return InkWell(
       onTap: () {
-        if (onSelect != null) {
-          onSelect(discount);
+        if (onSelect != null && discount != null) {
+        onSelect!(discount!);
         }
       },
       child: Container(
@@ -49,7 +48,7 @@ class DiscountListRow extends StatelessWidget {
                           Padding(
                             padding: const EdgeInsets.only(left: 8.0),
                             child: new Text(
-                              discount.code ?? "",
+                              discount?.code ?? "",
                               style: new TextStyle(
                                   fontSize: 15.0, color: Colors.black),
                             ),
@@ -57,7 +56,7 @@ class DiscountListRow extends StatelessWidget {
                           Padding(
                             padding: const EdgeInsets.only(left: 10.0, top: 10),
                             child: new Text(
-                              discount.customerName ?? "",
+                              discount?.customerName ?? "",
                               style: new TextStyle(
                                   fontSize: 15.0, color: Colors.grey),
                             ),
@@ -73,14 +72,14 @@ class DiscountListRow extends StatelessWidget {
               children: <Widget>[
                 Padding(
                   padding: const EdgeInsets.all(0),
-                  child: Text(discount.status),
+                  child: Text(discount?.status ?? ''),
                 ),
                 Padding(
                   padding: const EdgeInsets.only(left: 8.0, top: 5, bottom: 5),
                   child: Row(
                     children: <Widget>[
                       new Text(
-                        "${discount.amount.toStringAsFixed(2) ?? ''}",
+                        "${discount?.amount.toStringAsFixed(2) ?? ''}",
                         style:
                             new TextStyle(fontSize: 15.0, color: Colors.grey),
                       ),