Added shopping cart and sorting to Shrine (#4616)

examples/flutter_gallery/lib/demo/shrine/shrine_home.dart

@@ -15,7 +15,8 @@ import 'shrine_types.dart';
 
 const double unitSize = kToolBarHeight;
 
-Map<Product, Order> shoppingCart = <Product, Order>{};
+final List<Product> _products = new List<Product>.from(allProducts());
+final Map<Product, Order> _shoppingCart = <Product, Order>{};
 
 /// Displays the Vendor's name and avatar.
 class VendorItem extends StatelessWidget {
@@ -63,7 +64,7 @@ abstract class PriceItem extends StatelessWidget {
 
   Widget buildItem(BuildContext context, TextStyle style, EdgeInsets padding) {
     BoxDecoration decoration;
-    if (shoppingCart[product] != null)
+    if (_shoppingCart[product] != null)
       decoration = new BoxDecoration(backgroundColor: const Color(0xFFFFE0E0));
 
     return new Container(
@@ -259,18 +260,16 @@ class ShrineHome extends StatefulWidget {
 }
 
 class _ShrineHomeState extends State<ShrineHome> {
-  final List<Product> _products = allProducts();
+  static final GlobalKey<ScaffoldState> scaffoldKey = new GlobalKey<ScaffoldState>(debugLabel: 'Order page');
 
   void handleCompletedOrder(Order completedOrder) {
     assert(completedOrder.product != null);
-    if (completedOrder.inCart && completedOrder.quantity > 0)
-      shoppingCart[completedOrder.product] = completedOrder;
-    else
-      shoppingCart[completedOrder.product] = null;
+    if (completedOrder.quantity == 0)
+      _shoppingCart.remove(completedOrder.product);
   }
 
   void showOrderPage(Product product) {
-    final Order order = shoppingCart[product] ?? new Order(product: product);
+    final Order order = _shoppingCart[product] ?? new Order(product: product);
     final Completer<Order> completer = new Completer<Order>();
     final Key productKey = new ObjectKey(product);
     final Set<Key> mostValuableKeys = new HashSet<Key>();
@@ -282,7 +281,8 @@ class _ShrineHomeState extends State<ShrineHome> {
       builder: (BuildContext context) {
         return new OrderPage(
           order: order,
-          products: _products
+          products: _products,
+          shoppingCart: _shoppingCart
         );
       }
     ));
@@ -293,6 +293,9 @@ class _ShrineHomeState extends State<ShrineHome> {
   Widget build(BuildContext context) {
     final Product featured = _products.firstWhere((Product product) => product.featureDescription != null);
     return new ShrinePage(
+      scaffoldKey: scaffoldKey,
+      products: _products,
+      shoppingCart: _shoppingCart,
       body: new ScrollableViewport(
         child: new RepaintBoundary(
           child: new Column(

examples/flutter_gallery/lib/demo/shrine/shrine_order.dart

@@ -118,13 +118,15 @@ class OrderItem extends StatelessWidget {
 }
 
 class OrderPage extends StatefulWidget {
-  OrderPage({ Key key, this.order, this.products }) : super(key: key) {
+  OrderPage({ Key key, this.order, this.products, this.shoppingCart }) : super(key: key) {
     assert(order != null);
     assert(products != null && products.length > 0);
+    assert(shoppingCart != null);
   }
 
   final Order order;
   final List<Product> products;
+  final Map<Product, Order> shoppingCart;
 
   @override
   _OrderPageState createState() => new _OrderPageState();
@@ -134,7 +136,7 @@ class OrderPage extends StatefulWidget {
 /// arranged in two columns. Enables the user to specify a quantity and add an
 /// order to the shopping cart.
 class _OrderPageState extends State<OrderPage> {
-  final GlobalKey<ScaffoldState> scaffoldKey = new GlobalKey<ScaffoldState>(debugLabel: 'Order Page');
+  static final GlobalKey<ScaffoldState> scaffoldKey = new GlobalKey<ScaffoldState>(debugLabel: 'Order page');
 
   Order get currentOrder => ShrineOrderRoute.of(context).order;
 
@@ -146,6 +148,7 @@ class _OrderPageState extends State<OrderPage> {
     Order newOrder = currentOrder.copyWith(quantity: quantity, inCart: inCart);
     if (currentOrder != newOrder) {
       setState(() {
+        config.shoppingCart[newOrder.product] = newOrder;
         currentOrder = newOrder;
       });
     }
@@ -159,12 +162,15 @@ class _OrderPageState extends State<OrderPage> {
   Widget build(BuildContext context) {
     return new ShrinePage(
       scaffoldKey: scaffoldKey,
+      products: config.products,
+      shoppingCart: config.shoppingCart,
       floatingActionButton: new FloatingActionButton(
         onPressed: () {
           updateOrder(inCart: true);
           final int n = currentOrder.quantity;
+          final String item = currentOrder.product.name;
           showSnackBarMessage(
-            'There ${ n == 1 ? "is one item" : "are $n items" } in the shopping cart.'
+            'There ${ n == 1 ? "is one $item item" : "are $n $item items" } in the shopping cart.'
           );
         },
         backgroundColor: const Color(0xFF16F0F0),

examples/flutter_gallery/lib/demo/shrine/shrine_page.dart

@@ -5,6 +5,7 @@
 import 'package:flutter/material.dart';
 
 import 'shrine_theme.dart';
+import 'shrine_types.dart';
 
 enum ShrineAction {
   sortByPrice,
@@ -13,11 +14,23 @@ enum ShrineAction {
 }
 
 class ShrinePage extends StatefulWidget {
-  ShrinePage({ Key key, this.scaffoldKey, this.body, this.floatingActionButton }) : super(key: key);
+  ShrinePage({
+    Key key,
+    this.scaffoldKey,
+    this.body,
+    this.floatingActionButton,
+    this.products,
+    this.shoppingCart
+  }) : super(key: key) {
+    assert(body != null);
+    assert(scaffoldKey != null);
+  }
 
-  final Key scaffoldKey;
+  final GlobalKey<ScaffoldState> scaffoldKey;
   final Widget body;
   final Widget floatingActionButton;
+  final List<Product> products;
+  final Map<Product, Order> shoppingCart;
 
   @override
   ShrinePageState createState() => new ShrinePageState();
@@ -37,6 +50,37 @@ class ShrinePageState extends State<ShrinePage> {
     return false;
   }
 
+  void _showShoppingCart() {
+    showModalBottomSheet/*<Null>*/(context: context, builder: (BuildContext context) {
+      if (config.shoppingCart.isEmpty) {
+        return new Padding(
+          padding: const EdgeInsets.all(24.0),
+          child: new Text('The shopping cart is empty')
+        );
+      }
+      return new MaterialList(children: config.shoppingCart.values.map((Order order) {
+        return new ListItem(
+          title: new Text(order.product.name),
+          leading: new Text('${order.quantity}'),
+          subtitle: new Text(order.product.vendor.name)
+        );
+      }).toList());
+    });
+  }
+
+  void _sortByPrice() {
+    config.products.sort((Product a, Product b) => a.price.compareTo(b.price));
+  }
+
+  void _sortByProduct() {
+    config.products.sort((Product a, Product b) => a.name.compareTo(b.name));
+  }
+
+  void _emptyCart() {
+    config.shoppingCart.clear();
+    config.scaffoldKey.currentState.showSnackBar(new SnackBar(content: new Text('Shopping cart is empty')));
+  }
+
   @override
   Widget build(BuildContext context) {
     return new Scaffold(
@@ -59,7 +103,7 @@ class ShrinePageState extends State<ShrinePage> {
             icon: Icons.shopping_cart,
             tooltip: 'Shopping cart',
             onPressed: () {
-              // TODO(hansmuller): implement the action.
+              _showShoppingCart();
             }
           ),
           new PopupMenuButton<ShrineAction>(
@@ -80,13 +124,13 @@ class ShrinePageState extends State<ShrinePage> {
             onSelected: (ShrineAction action) {
               switch (action) {
                 case ShrineAction.sortByPrice:
-                  // TODO(hansmuller): implement the action.
+                  setState(_sortByPrice);
                   break;
                 case ShrineAction.sortByProduct:
-                  // TODO(hansmuller): implement the action.
+                  setState(_sortByProduct);
                   break;
                 case ShrineAction.emptyCart:
-                  // TODO(hansmuller): implement the action.
+                  setState(_emptyCart);
                   break;
               }
             }