kline_chart 1.0.0

Flutter native candlestick chart without dependencies, high performance, smooth scrolling, supports multiple indicators

KLine Chart

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KLine Chart is a lightweight Flutter charting library for building interactive financial candlestick charts. It supports common technical indicators such as MA, EMA, BOLL, SAR, VOL, MACD, KDJ, RSI, WR, and OBV, along with smooth scrolling, zooming, long-press crosshair interaction, and detailed price/indicator overlays.

It is designed for crypto, stock, and trading-related apps that need a customizable, responsive K-line chart component.

Demo

Features

• Candlestick and time chart modes.
• Smooth horizontal scrolling and pinch-to-zoom.
• Long-press crosshair with candle detail overlay.
• Main indicators: MA, EMA, BOLL, SAR.
• Sub indicators: VOL, MACD, KDJ, RSI, WR, OBV.
• Configurable indicator periods, colors, spacing, and visible item count.
• Rendering stability for short data sets, flat price data, and zero volume data.

Installation

Add the package to your Flutter project:

dependencies:
  kline_chart: ^1.0.0

Then import it:

import 'package:kline_chart/kline_chart.dart';

Quick Start

Provide K-line data through KLineController.shared.data, then render KLineView.

import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart' show rootBundle;
import 'package:kline_chart/kline_chart.dart';

class KLinePage extends StatefulWidget {
  const KLinePage({super.key});

  @override
  State<KLinePage> createState() => _KLinePageState();
}

class _KLinePageState extends State<KLinePage> {
  @override
  void initState() {
    super.initState();
    _loadData();
  }

  Future<void> _loadData() async {
    final jsonStr = await rootBundle.loadString('assets/kline.json');
    final jsonList = json.decode(jsonStr) as List;

    KLineController.shared.data = jsonList.map((item) {
      return KLineData(
        open: double.parse(item[1] ?? '0'),
        high: double.parse(item[2] ?? '0'),
        low: double.parse(item[3] ?? '0'),
        close: double.parse(item[4] ?? '0'),
        volume: double.parse(item[5] ?? '0'),
        time: item[6] ?? 0,
      );
    }).toList();

    setState(() {});
  }

  @override
  Widget build(BuildContext context) {
    return const SizedBox(
      height: 400,
      child: KLineView(),
    );
  }
}

Indicator Configuration

KLineController.shared is the central configuration object. Update it before rebuilding KLineView.

final controller = KLineController.shared;

controller.showMainIndicators = [IndicatorType.ma];
controller.showSubIndicators = [
  IndicatorType.vol,
  IndicatorType.macd,
];

controller.volMaPeriods = [7, 14];
controller.macdPeriods = [12, 26, 9];
controller.kdjPeriods = [9, 3, 3];
controller.rsiPeriods = [6, 12, 24];
controller.wrPeriods = [7, 14];
controller.bollPeriod = 21;
controller.bollBandwidth = 2;
controller.sarStart = 0.02;
controller.sarIncrement = 0.02;
controller.sarMax = 0.2;
controller.sarColor = Colors.orange;

Available indicator types:

Area	Indicators
Main chart	ma, ema, boll, sar
Sub chart	vol, macd, kdj, rsi, wr, obv

Chart Configuration

final controller = KLineController.shared;

controller.itemCount = 30;
controller.minCount = 7;
controller.maxCount = 39;
controller.spacing = 2.0;
controller.showTimeChart = false;

controller.klineMargin = const EdgeInsets.all(0);
controller.subIndicatorHeight = 50.0;
controller.indicatorSpacing = 10.0;
controller.indicatorColors = [
  Colors.orange,
  Colors.purple,
  Colors.blue,
];
controller.sarColor = Colors.orange;

For detailed style properties and examples, see Style API.

Data Model

Each candle is represented by KLineData.

KLineData(
  open: 100.0,
  high: 110.0,
  low: 95.0,
  close: 105.0,
  volume: 12345.0,
  time: 1710000000000,
);

The time value is expected to be a Unix timestamp in milliseconds.

Example

The repository includes a runnable example app under example/.

cd example
flutter run

Roadmap

• Improved responsive behavior across screen sizes.
• Continued performance optimization.