🚀 2단계 InheritedWidget 사용하기

lib/cart_screen.dart

@@ -4,6 +4,7 @@ import 'models/payment.dart';
 import 'models/product.dart';
 import 'models/shop.dart';
 import 'utils/formatter.dart';
+import 'widgets/cart_item_counter.dart';
 import 'widgets/payment_info.dart';
 import 'widgets/shop_info.dart';
 

lib/widgets/cart_item.dart

@@ -78,6 +78,15 @@ class CartItem extends StatelessWidget {
               ),
             ],
           ),
+          Row(
+            mainAxisAlignment: MainAxisAlignment.end,
+            children: [
+              CartItemCounter(),
+              SizedBox(
+                width: 20,
+              ),
+            ],
+          ),
           SizedBox(
             height: 20,
           ),

lib/widgets/cart_item_counter.dart

@@ -0,0 +1,32 @@
+import 'package:flutter/material.dart';
+
+class CartItemCounter extends StatelessWidget {
+  const CartItemCounter({Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      decoration: BoxDecoration(
+        border: Border.all(
+          color: Colors.grey.withOpacity(0.4),
+        ),
+        borderRadius: BorderRadius.circular(6),
+      ),
+      child: Wrap(
+        crossAxisAlignment: WrapCrossAlignment.center,
+        children: [
+          IconButton(
+            icon: Icon(Icons.remove),
+            disabledColor: Colors.grey,
+            onPressed: () {},
+          ),
+          Text('1'),
+          IconButton(
+            icon: Icon(Icons.add),
+            onPressed: () {},
+          ),
+        ],
+      ),
+    );
+  }
+}

lib/widgets/counter.dart

@@ -0,0 +1,23 @@
+import 'package:flutter/material.dart';
+
+class Counter extends InheritedWidget {
+  const Counter({
+    Key? key,
+    required this.value,
+    required Widget child,
+  }) : super(key: key, child: child);
+
+  final int value;
+
+  static Counter of(BuildContext context) {
+    final Counter? result =
+        context.dependOnInheritedWidgetOfExactType<Counter>();
+    assert(result != null, 'No Counter found in context');
+    return result!;
+  }
+
+  @override
+  bool updateShouldNotify(Counter old) {
+    return old.value != value;
+  }
+}