candlesticks 1.1.1 candlesticks: ^1.1.1 copied to clipboard
A flutter candlesticks chart for android, ios and the web; It contains optimized animations, indicators (soon) and socket connection ability.
import 'dart:convert';
import 'package:example/repository.dart';
import 'package:flutter/material.dart';
import 'package:candlesticks/candlesticks.dart';
import 'package:web_socket_channel/web_socket_channel.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'candleSticks',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
List<Candle> candles = [];
WebSocketChannel? _channel;
String interval = "1m";
void binanceFetch(String interval) {
fetchCandles(symbol: "BTCUSDT", interval: interval).then(
(value) => setState(
() {
this.interval = interval;
candles = value;
},
),
);
if (_channel != null) _channel!.sink.close();
_channel = WebSocketChannel.connect(
Uri.parse('wss://stream.binance.com:9443/ws'),
);
_channel!.sink.add(
jsonEncode(
{
"method": "SUBSCRIBE",
"params": ["btcusdt@kline_" + interval],
"id": 1
},
),
);
}
@override
void initState() {
binanceFetch("1m");
super.initState();
}
@override
void dispose() {
if (_channel != null) _channel!.sink.close();
super.dispose();
}
void updateCandlesFromSnapshot(AsyncSnapshot<Object?> snapshot) {
if (snapshot.data != null) {
final data = jsonDecode(snapshot.data as String) as Map<String, dynamic>;
if (data.containsKey("k") == true &&
candles[0].date.millisecondsSinceEpoch == data["k"]["t"]) {
candles[0] = Candle(
date: candles[0].date,
high: double.parse(data["k"]["h"]),
low: double.parse(data["k"]["l"]),
open: double.parse(data["k"]["o"]),
close: double.parse(data["k"]["c"]),
volume: double.parse(data["k"]["v"]));
} else if (data.containsKey("k") == true &&
data["k"]["t"] - candles[0].date.millisecondsSinceEpoch ==
candles[0].date.millisecondsSinceEpoch -
candles[1].date.millisecondsSinceEpoch) {
candles.insert(
0,
Candle(
date: DateTime.fromMillisecondsSinceEpoch(data["k"]["t"]),
high: double.parse(data["k"]["h"]),
low: double.parse(data["k"]["l"]),
open: double.parse(data["k"]["o"]),
close: double.parse(data["k"]["c"]),
volume: double.parse(data["k"]["v"])));
}
}
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("candleSticks"),
),
body: Center(
child: AspectRatio(
aspectRatio: 1.2,
child: StreamBuilder(
stream: _channel == null ? null : _channel!.stream,
builder: (context, snapshot) {
updateCandlesFromSnapshot(snapshot);
return Candlesticks(
onIntervalChange: (String value) async {
binanceFetch(value);
},
candles: candles,
interval: interval,
);
},
),
),
),
);
}
}