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 Container(
      padding: const EdgeInsets.all(20.0),
      child: Column(
        children: <Widget>[
          Row(
            children: <Widget>[
              Text(
                '${stock.symbol}',
                style: Theme.of(context).textTheme.display2
              ),
              arrow,
            ],
            mainAxisAlignment: MainAxisAlignment.spaceBetween
          ),
          Text('Last Sale', style: headings),
          Text('$lastSale ($changeInPrice)'),
          Container(
            height: 8.0
          ),
          Text('Market Cap', style: headings),
          Text('${stock.marketCap}'),
          Container(
            height: 8.0
          ),
          RichText(
            text: TextSpan(
              style: DefaultTextStyle.of(context).style.merge(const TextStyle(fontSize: 8.0)),
              text: 'Prices may be delayed by ',
              children: const <TextSpan>[
                TextSpan(text: 'several', style: TextStyle(fontStyle: FontStyle.italic)),
                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 AnimatedBuilder(
      animation: stocks,
      builder: (BuildContext context, Widget child) {
        final Stock stock = stocks[symbol];
        return Scaffold(
          appBar: AppBar(
            title: Text(stock?.name ?? symbol)
          ),
          body: SingleChildScrollView(
            child: Container(
              margin: const EdgeInsets.all(20.0),
              child: Card(
                child: AnimatedCrossFade(
                  duration: const Duration(milliseconds: 300),
                  firstChild: const Padding(
                    padding: EdgeInsets.all(20.0),
                    child: Center(child: CircularProgressIndicator()),
                  ),
                  secondChild: stock != null
                    ? _StockSymbolView(
                      stock: stock,
                      arrow: Hero(
                        tag: stock,
                        child: StockArrow(percentChange: stock.percentChange),
                      ),
                    ) : Padding(
                        padding: const EdgeInsets.all(20.0),
                        child: Center(child: 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 Container(
      padding: const EdgeInsets.all(10.0),
      decoration: const BoxDecoration(
        border: Border(top: BorderSide(color: Colors.black26))
      ),
      child: _StockSymbolView(
        stock: stock,
        arrow: StockArrow(percentChange: stock.percentChange)
      )
   );
  }
}