gistfile1.txt

import 'dart:math';

/// Timeseries chart example
import 'package:charts_flutter/flutter.dart' as charts;
import 'package:charts_flutter/flutter.dart';
import 'package:flutter/material.dart';
import 'package:flutter/scheduler.dart';

const String FIRST_SEL = 'FIRST';

final data_a = [
  new TimeSeriesSales(new DateTime(2017, 9, 1), 5),
  new TimeSeriesSales(new DateTime(2017, 9, 4), 7),
  new TimeSeriesSales(new DateTime(2017, 9, 6), 9),
  new TimeSeriesSales(new DateTime(2017, 9, 8), 10),
];

class SimpleTimeSeriesChart extends StatefulWidget {
  final List<charts.Series> seriesList;
  SimpleTimeSeriesChart(this.seriesList, {this.animate});
  final bool animate;

  /// Creates a [TimeSeriesChart] with sample data and no transition.
  factory SimpleTimeSeriesChart.withSampleData() {
    return new SimpleTimeSeriesChart(
      _createSampleData(),
      // Disable animations for image tests.
      animate: false,

    );
  }

  /// Create one series with sample hard coded data.
  static List<charts.Series<TimeSeriesSales, int>> _createSampleData() {

    return [
      charts.Series<TimeSeriesSales, int>(
        id: 'sales_a',
        domainFn: (TimeSeriesSales sales, _) => sales.time,
        measureFn: (TimeSeriesSales sales, _) => sales.sales,
        data: data_a,
      ),
    ];

  }

  SimpleTimeSeriesChartState createState() => SimpleTimeSeriesChartState();

}

class SimpleTimeSeriesChartState extends State<SimpleTimeSeriesChart> {


   _onSliderChange(Point<int> point, dynamic domain, String roleId,
    charts.SliderListenerDragState dragState) {
      void rebuild(_) {
        // @NOTE commenting out the following line makes it work
        setState(() { });
      }
      SchedulerBinding.instance.addPostFrameCallback(rebuild);
    }

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding:EdgeInsets.all(10.0),
      child: SizedBox(
        height:300.0,
        child: charts.LineChart(
          widget.seriesList,
          animate: widget.animate,
          defaultInteractions: false,
          // Optionally pass in a [DateTimeFactory] used by the chart. The factory
          // should create the same type of [DateTime] as the data provided. If none
          // specified, the default creates local date time.
          // @NOTE commenting out the following line makes it work
//          defaultRenderer: charts.LineRendererConfig(includePoints: true),
          behaviors: [
            charts.Slider(
              initialDomainValue:data_a.first.time,
              onChangeCallback: _onSliderChange,
              snapToDatum: true,
              style:SliderStyle(handleSize:const Rectangle(0,0,8,25)),
              roleId:FIRST_SEL
            ),
          ],
        ),
      ),
    );
  }


}

/// Sample time series data type.
class TimeSeriesSales {
  final DateTime _time;
  final int sales;

  int get time {
    return _time.day;
  }

  TimeSeriesSales(this._time, this.sales);
}