Add randomly generated radials example

example/animated_random_radial_chart_example.dart

@@ -0,0 +1,75 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_circular_chart/flutter_circular_chart.dart';
+import 'dart:math' as Math;
+
+import 'color_palette.dart';
+
+void main() {
+  runApp(new MaterialApp(
+    home: new RandomizedRadialChartExample(),
+  ));
+}
+
+class RandomizedRadialChartExample extends StatefulWidget {
+  @override
+  _RandomizedRadialChartExampleState createState() =>
+      new _RandomizedRadialChartExampleState();
+}
+
+class _RandomizedRadialChartExampleState
+    extends State<RandomizedRadialChartExample> {
+  final GlobalKey<AnimatedCircularChartState> _chartKey =
+      new GlobalKey<AnimatedCircularChartState>();
+  final _chartSize = const Size(300.0, 300.0);
+  final Math.Random random = new Math.Random();
+  List<CircularStackEntry> data;
+
+  @override
+  void initState() {
+    data = _generateRandomData();
+  }
+
+  double value = 50.0;
+
+  void _randomize() {
+    setState(() {
+      data = _generateRandomData();
+      _chartKey.currentState.updateData(data);
+    });
+  }
+
+  List<CircularStackEntry> _generateRandomData() {
+    int stackCount = random.nextInt(10);
+    List<CircularStackEntry> data = new List.generate(stackCount, (i) {
+      int segCount = random.nextInt(10);
+      List<CircularSegmentEntry> segments =  new List.generate(segCount, (j) {
+        Color randomColor = ColorPalette.primary.random(random);
+        return new CircularSegmentEntry(random.nextDouble(), randomColor);
+      });
+      return new CircularStackEntry(segments);
+    });
+
+    return data;
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return new Scaffold(
+      appBar: new AppBar(
+        title: const Text('Randomized radial data'),
+      ),
+      body: new Center(
+        child: new AnimatedCircularChart(
+          key: _chartKey,
+          size: _chartSize,
+          initialChartData: data,
+          chartType: CircularChartType.Radial,
+        ),
+      ),
+      floatingActionButton: new FloatingActionButton(
+        onPressed: _randomize,
+        child: const Icon(Icons.refresh),
+      ),
+    );
+  }
+}

example/color_palette.dart

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+import 'dart:math';
+
+import 'package:flutter/material.dart';
+
+class ColorPalette {
+  static final ColorPalette primary = new ColorPalette(<Color>[
+    Colors.blue[400],
+    Colors.blue[200],
+    Colors.red[400],
+    Colors.red[200],
+    Colors.green[400],
+    Colors.green[200],
+    Colors.yellow[400],
+    Colors.yellow[200],
+    Colors.purple[400],
+    Colors.purple[200],
+    Colors.orange[400],
+    Colors.orange[200],
+    Colors.teal[400],
+    Colors.teal[200],
+    Colors.black,
+  ]);
+
+  ColorPalette(List<Color> colors) : _colors = colors {
+    assert(colors.isNotEmpty);
+  }
+
+  final List<Color> _colors;
+
+  Color operator [](int index) => _colors[index % length];
+
+  int get length => _colors.length;
+
+  Color random(Random random) => this[random.nextInt(length)];
+}