add packages, receiving & processing

lib/pages/discount/discount_list.dart

@@ -4,6 +4,7 @@ import 'package:fcs/pages/discount/model/discount_model.dart';
 import 'package:fcs/pages/main/util.dart';
 import 'package:fcs/pages/widgets/bottom_up_page_route.dart';
 import 'package:fcs/pages/widgets/progress.dart';
+import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
 
@@ -29,7 +30,7 @@ class _DiscountListState extends State<DiscountList> {
             AppTranslations.of(context).text("discount.title"),
           ),
           leading: new IconButton(
-            icon: new Icon(Icons.close),
+            icon: new Icon(CupertinoIcons.back),
             onPressed: () => Navigator.of(context).pop(),
           ),
           backgroundColor: primaryColor,