112 lines
3.4 KiB
Markdown
112 lines
3.4 KiB
Markdown
# Flutter Circular Chart
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A library for creating animated circular chart widgets with Flutter, inspired by [Zero to One with Flutter](https://medium.com/dartlang/zero-to-one-with-flutter-43b13fd7b354).
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## Overview
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Create easily animated pie charts and radial charts by providing them with data objects they can plot into charts and animate between.
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Check the examples folder for the source code for the above screenshots.
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## Contents:
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- [Installation](#installation)
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- [Getting Started](#getting-started)
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- [Details](#details)
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- [Chart data entries](#chart-data-entries)
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## Installation
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__Note:__ This is a WIP early implementation, use at your own risk. You can install it by including this git repository in your package dependencies:
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```
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dependencies:
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flutter_circular_chart:
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git:
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url: git://github.com/xqwzts/flutter_circular_chart.git
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```
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## Getting Started
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Import the package:
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```dart
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import 'package:flutter_circular_chart/flutter_circular_chart.dart';
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```
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Create a [GlobalKey](https://docs.flutter.io/flutter/widgets/GlobalKey-class.html) to be able to access the chart and update its data:
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```dart
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final GlobalKey<AnimatedCircularChartState> _chartKey = new GlobalKey<AnimatedCircularChartState>();
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```
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Create chart data entry objects:
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```dart
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List<CircularStackEntry> data = <CircularStackEntry>[
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new CircularStackEntry(
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<CircularSegmentEntry>[
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new CircularSegmentEntry(500.0, Colors.red[200], rankKey: 'Q1'),
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new CircularSegmentEntry(1000.0, Colors.green[200], rankKey: 'Q2'),
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new CircularSegmentEntry(2000.0, Colors.blue[200], rankKey: 'Q3'),
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new CircularSegmentEntry(1000.0, Colors.yellow[200], rankKey: 'Q4'),
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],
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rankKey: 'Quarterly Profits',
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),
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];
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```
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Create an `AnimatedCircularChart`, passing it the `_chartKey` and initial `data`:
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```dart
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@override
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Widget build(BuildContext context) {
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return new AnimatedCircularChart(
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key: _chartKey,
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size: const Size(300.0, 300.0),
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initialChartData: data,
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chartType: CircularChartType.Pie,
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);
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}
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```
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Call `updateData` to animate the chart:
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```dart
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void _cycleSamples() {
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List<CircularStackEntry> nextData = <CircularStackEntry>[
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new CircularStackEntry(
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<CircularSegmentEntry>[
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new CircularSegmentEntry(1500.0, Colors.red[200], rankKey: 'Q1'),
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new CircularSegmentEntry(750.0, Colors.green[200], rankKey: 'Q2'),
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new CircularSegmentEntry(2000.0, Colors.blue[200], rankKey: 'Q3'),
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new CircularSegmentEntry(1000.0, Colors.yellow[200], rankKey: 'Q4'),
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],
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rankKey: 'Quarterly Profits',
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),
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];
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setState(() {
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_chartKey.currentState.updateData(nextData);
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});
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}
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```
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## Details
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### Chart data entries:
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Charts expect a list of `CircularStackEntry` objects containing the data they need to be drawn.
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Each `CircularStackEntry` corresponds to a complete circle in the chart. For radial charts that is one of the rings, for pie charts it is the whole pie.
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Radial charts with multiple `CircularStackEntry`s will display them as concentric circles.
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Each `CircularStackEntry` is composed of multiple `CircularSegmentEntry`s containing the value of a data point. In radial charts a segment corresponds to an arc segment of the current ring, for pie charts it is an individual slice.
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