samples/web/gallery/lib/demo/shrine/shrine_page.dart

// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'package:flutter_web/material.dart';

import 'shrine_theme.dart';
import 'shrine_types.dart';

enum ShrineAction { sortByPrice, sortByProduct, emptyCart }

class ShrinePage extends StatefulWidget {
  const ShrinePage(
      {Key key,
      @required this.scaffoldKey,
      @required this.body,
      this.floatingActionButton,
      this.products,
      this.shoppingCart})
      : assert(body != null),
        assert(scaffoldKey != null),
        super(key: key);

  final GlobalKey<ScaffoldState> scaffoldKey;
  final Widget body;
  final Widget floatingActionButton;
  final List<Product> products;
  final Map<Product, Order> shoppingCart;

  @override
  ShrinePageState createState() => ShrinePageState();
}

/// Defines the Scaffold, AppBar, etc that the demo pages have in common.
class ShrinePageState extends State<ShrinePage> {
  double _appBarElevation = 0.0;

  bool _handleScrollNotification(ScrollNotification notification) {
    final double elevation =
        notification.metrics.extentBefore <= 0.0 ? 0.0 : 1.0;
    if (elevation != _appBarElevation) {
      setState(() {
        _appBarElevation = elevation;
      });
    }
    return false;
  }

  void _showShoppingCart() {
    showModalBottomSheet<void>(
        context: context,
        builder: (BuildContext context) {
          if (widget.shoppingCart.isEmpty) {
            return const Padding(
                padding: EdgeInsets.all(24.0),
                child: Text('The shopping cart is empty'));
          }
          return ListView(
            padding: kMaterialListPadding,
            children: widget.shoppingCart.values.map((Order order) {
              return ListTile(
                  title: Text(order.product.name),
                  leading: Text('${order.quantity}'),
                  subtitle: Text(order.product.vendor.name));
            }).toList(),
          );
        });
  }

  void _sortByPrice() {
    widget.products.sort((Product a, Product b) => a.price.compareTo(b.price));
  }

  void _sortByProduct() {
    widget.products.sort((Product a, Product b) => a.name.compareTo(b.name));
  }

  void _emptyCart() {
    widget.shoppingCart.clear();
    widget.scaffoldKey.currentState
        .showSnackBar(const SnackBar(content: Text('Shopping cart is empty')));
  }

  @override
  Widget build(BuildContext context) {
    final ShrineTheme theme = ShrineTheme.of(context);
    return Scaffold(
        key: widget.scaffoldKey,
        appBar: AppBar(
            elevation: _appBarElevation,
            backgroundColor: theme.appBarBackgroundColor,
            iconTheme: Theme.of(context).iconTheme,
            brightness: Brightness.light,
            flexibleSpace: Container(
                decoration: BoxDecoration(
                    border:
                        Border(bottom: BorderSide(color: theme.dividerColor)))),
            title:
                Text('SHRINE', style: ShrineTheme.of(context).appBarTitleStyle),
            centerTitle: true,
            actions: <Widget>[
              IconButton(
                  icon: const Icon(Icons.shopping_cart),
                  tooltip: 'Shopping cart',
                  onPressed: _showShoppingCart),
              PopupMenuButton<ShrineAction>(
                  itemBuilder: (BuildContext context) =>
                      <PopupMenuItem<ShrineAction>>[
                        const PopupMenuItem<ShrineAction>(
                            value: ShrineAction.sortByPrice,
                            child: Text('Sort by price')),
                        const PopupMenuItem<ShrineAction>(
                            value: ShrineAction.sortByProduct,
                            child: Text('Sort by product')),
                        const PopupMenuItem<ShrineAction>(
                            value: ShrineAction.emptyCart,
                            child: Text('Empty shopping cart'))
                      ],
                  onSelected: (ShrineAction action) {
                    switch (action) {
                      case ShrineAction.sortByPrice:
                        setState(_sortByPrice);
                        break;
                      case ShrineAction.sortByProduct:
                        setState(_sortByProduct);
                        break;
                      case ShrineAction.emptyCart:
                        setState(_emptyCart);
                        break;
                    }
                  })
            ]),
        floatingActionButton: widget.floatingActionButton,
        body: NotificationListener<ScrollNotification>(
            onNotification: _handleScrollNotification, child: widget.body));
  }
}