flutter/examples/stocks/lib/stock_symbol_viewer.dart

// Copyright 2015 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/material.dart';

import 'stock_arrow.dart';
import 'stock_data.dart';

class _StockSymbolView extends StatelessWidget {
  const _StockSymbolView({ this.stock, this.arrow });

  final Stock stock;
  final Widget arrow;

  @override
  Widget build(BuildContext context) {
    assert(stock != null);
    final String lastSale = "\$${stock.lastSale.toStringAsFixed(2)}";
    String changeInPrice = "${stock.percentChange.toStringAsFixed(2)}%";
    if (stock.percentChange > 0)
      changeInPrice = "+" + changeInPrice;

    final TextStyle headings = Theme.of(context).textTheme.body2;
    return new Container(
      padding: const EdgeInsets.all(20.0),
      child: new Column(
        children: <Widget>[
          new Row(
            children: <Widget>[
              new Text(
                '${stock.symbol}',
                style: Theme.of(context).textTheme.display2
              ),
              arrow,
            ],
            mainAxisAlignment: MainAxisAlignment.spaceBetween
          ),
          new Text('Last Sale', style: headings),
          new Text('$lastSale ($changeInPrice)'),
          new Container(
            height: 8.0
          ),
          new Text('Market Cap', style: headings),
          new Text('${stock.marketCap}'),
          new Container(
            height: 8.0
          ),
          new RichText(
            text: new TextSpan(
              style: DefaultTextStyle.of(context).style.merge(const TextStyle(fontSize: 8.0)),
              text: 'Prices may be delayed by ',
              children: <TextSpan>[
                const TextSpan(text: 'several', style: const TextStyle(fontStyle: FontStyle.italic)),
                const TextSpan(text: ' years.'),
              ]
            )
          ),
        ],
        mainAxisSize: MainAxisSize.min
      )
    );
  }
}

class StockSymbolPage extends StatelessWidget {
  const StockSymbolPage({ this.symbol, this.stocks });

  final String symbol;
  final StockData stocks;

  @override
  Widget build(BuildContext context) {
    return new AnimatedBuilder(
      animation: stocks,
      builder: (BuildContext context, Widget child) {
        final Stock stock = stocks[symbol];
        return new Scaffold(
          appBar: new AppBar(
            title: new Text(stock?.name ?? symbol)
          ),
          body: new SingleChildScrollView(
            child: new Container(
              margin: const EdgeInsets.all(20.0),
              child: new Card(
                child: new AnimatedCrossFade(
                  duration: const Duration(milliseconds: 300),
                  firstChild: const Padding(
                    padding: const EdgeInsets.all(20.0),
                    child: const Center(child: const CircularProgressIndicator()),
                  ),
                  secondChild: stock != null
                    ? new _StockSymbolView(
                      stock: stock,
                      arrow: new Hero(
                        tag: stock,
                        child: new StockArrow(percentChange: stock.percentChange),
                      ),
                    ) : new Padding(
                        padding: const EdgeInsets.all(20.0),
                        child: new Center(child: new Text('$symbol not found')),
                    ),
                  crossFadeState: stock == null && stocks.loading ? CrossFadeState.showFirst : CrossFadeState.showSecond,
                ),
              )
            )
          )
        );
      },
    );
  }
}

class StockSymbolBottomSheet extends StatelessWidget {
  const StockSymbolBottomSheet({ this.stock });

  final Stock stock;

  @override
  Widget build(BuildContext context) {
    return new Container(
      padding: const EdgeInsets.all(10.0),
      decoration: const BoxDecoration(
        border: const Border(top: const BorderSide(color: Colors.black26))
      ),
      child: new _StockSymbolView(
        stock: stock,
        arrow: new StockArrow(percentChange: stock.percentChange)
      )
   );
  }
}