blob: 35a79cae52e616b209ca18e5f8d97467d1954964 [file] [log] [blame]
// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Snapshot from http://www.nasdaq.com/screening/company-list.aspx
// Fetched 2/23/2014.
// "Symbol","Name","LastSale","MarketCap","IPOyear","Sector","industry","Summary Quote",
// Data in stock_data.json
import 'dart:convert';
import 'dart:math' as math;
import 'package:flutter/foundation.dart';
import 'package:http/http.dart' as http;
final math.Random _rng = math.Random();
class Stock {
Stock(this.symbol, this.name, this.lastSale, this.marketCap, this.percentChange);
Stock.fromFields(List<String> fields) {
// FIXME: This class should only have static data, not lastSale, etc.
// "Symbol","Name","LastSale","MarketCap","IPOyear","Sector","industry","Summary Quote",
lastSale = 0.0;
try {
lastSale = double.parse(fields[2]);
} catch (_) { }
symbol = fields[0];
name = fields[1];
marketCap = fields[4];
percentChange = (_rng.nextDouble() * 20) - 10;
}
String symbol;
String name;
double lastSale;
String marketCap;
double percentChange;
}
class StockData extends ChangeNotifier {
StockData() {
if (actuallyFetchData) {
_httpClient = http.Client();
_fetchNextChunk();
}
}
final List<String> _symbols = <String>[];
final Map<String, Stock> _stocks = <String, Stock>{};
List<String> get allSymbols => _symbols;
Stock operator [](String symbol) => _stocks[symbol];
bool get loading => _httpClient != null;
void add(List<dynamic> data) {
for (final List<dynamic> fields in data.cast<List<dynamic>>()) {
final Stock stock = Stock.fromFields(fields.cast<String>());
_symbols.add(stock.symbol);
_stocks[stock.symbol] = stock;
}
_symbols.sort();
notifyListeners();
}
static const int _chunkCount = 30;
int _nextChunk = 0;
String _urlToFetch(int chunk) {
return 'https://domokit.github.io/examples/stocks/data/stock_data_$chunk.json';
}
http.Client _httpClient;
static bool actuallyFetchData = true;
void _fetchNextChunk() {
_httpClient.get(_urlToFetch(_nextChunk++)).then<void>((http.Response response) {
final String json = response.body;
if (json == null) {
debugPrint('Failed to load stock data chunk ${_nextChunk - 1}');
_end();
return;
}
const JsonDecoder decoder = JsonDecoder();
add(decoder.convert(json) as List<dynamic>);
if (_nextChunk < _chunkCount) {
_fetchNextChunk();
} else {
_end();
}
});
}
void _end() {
_httpClient?.close();
_httpClient = null;
}
}