title: How to make a flutter chart line chart?
body: <p><a href="https://i.stack.imgur.com/t99s4.jpg" rel="nofollow noreferrer">this is my current graph look's like but i want to make tickProviderSpec as the average line
  </a></p>
  <p>This is what i have done. Is that possible to make a white line at the Center of line chart. Currently, Im using StaticNumericTickProviderSpec to draw the average line. I only need one average line in my line chart. Any idea to do this?</p>
  <pre><code>import 'package:charts_flutter/flutter.dart';
  import 'package:flutter/cupertino.dart';
  import 'package:charts_flutter/flutter.dart' as charts;
  class WeightTracker_time_series_chart extends StatelessWidget {
    final List&lt;charts.Series&gt; seriesList;
    final bool animate;
    WeightTracker_time_series_chart(this.seriesList, {this.animate});
  
    factory WeightTracker_time_series_chart.withSampleData() {
      return new WeightTracker_time_series_chart(
        _createSampleData(),
        animate: false,
      );
    }
    List getdata =[&quot;1&quot;,&quot;2&quot;,&quot;3&quot;];
  
    @override
    Widget build(BuildContext context) {
  
      return new charts.LineChart(seriesList,
  
          animate: animate,
          defaultRenderer: new charts.LineRendererConfig( includeArea: true,
            includePoints: true,
            includeLine: true,
            stacked: true,),
          layoutConfig: charts.LayoutConfig(
              leftMarginSpec: charts.MarginSpec.fixedPixel(60),
              topMarginSpec: charts.MarginSpec.fixedPixel(10),
              rightMarginSpec: charts.MarginSpec.fixedPixel(0),
              bottomMarginSpec: charts.MarginSpec.fixedPixel(20)
          ),
          flipVerticalAxis: false,
          defaultInteractions: false,
          behaviors: [new charts.PanAndZoomBehavior()],
          domainAxis: new charts.NumericAxisSpec(
            viewport: new charts.NumericExtents(20, 120),
              renderSpec: charts.GridlineRendererSpec(
                  lineStyle: charts.LineStyleSpec(
                    color: charts.MaterialPalette.white,
                    thickness: 1,
                  )
              ),
  
              tickProviderSpec: new charts.StaticNumericTickProviderSpec(
                // Create the ticks to be used the domain axis.
                  _createTickSpec(),
              )),
          selectionModels: [
            new charts.SelectionModelConfig(
                changedListener: (SelectionModel model) {
                  print( model.selectedSeries[0].measureFn(
                      model.selectedDatum[0].index));
                  }
            )
          ],
  
          primaryMeasureAxis: new charts.NumericAxisSpec(
              renderSpec:
              charts.GridlineRendererSpec(
                  labelOffsetFromAxisPx: 20,
  
                  labelAnchor: charts.TickLabelAnchor.before,
                  lineStyle: charts.LineStyleSpec(
                    color: charts.MaterialPalette.white,
                    thickness: 2,
                  )
              ),
              tickProviderSpec: new charts.StaticNumericTickProviderSpec(
  
                // Create the ticks to be used the domain axis.
                &lt;charts.TickSpec&lt;num&gt;&gt;[
  
  
                  new charts.TickSpec(50, label: '80 ', style: charts.TextStyleSpec(fontSize: 14)),
  
                ],
              )
  
          ),
          
    }
  
    List&lt;charts.TickSpec&lt;num&gt;&gt; _createTickSpec() {
      List&lt;charts.TickSpec&lt;num&gt;&gt; _tickProvidSpecs = new List&lt;charts.TickSpec&lt;num&gt;&gt;();
      double d = 0;
      double day= 0;
     for(int i = 0; i&lt; getdata.length ; i++) {
  
        _tickProvidSpecs.add(new charts.TickSpec(d,label: '$day%', style: charts.TextStyleSpec(fontSize: 14)));
        d +=20;
        day+=1;
      }
  
     return _tickProvidSpecs;
    }
  
  
    static List&lt;charts.Series&lt;day_kg, int&gt;&gt; _createSampleData() {
      final myFakeDesktopData = [
        new day_kg(0, 70),
        new day_kg(20, 85),
        new day_kg(40, 80),
  
      ];
  
      return [
        new charts.Series&lt;day_kg, int&gt;(
          id: 'weight',
          fillColorFn: (_, __) =&gt; charts.MaterialPalette.white,
          colorFn: (_, __) =&gt; charts.MaterialPalette.red.shadeDefault,
          domainFn: (day_kg data, _) =&gt; data.date,
          measureFn: (day_kg data, _) =&gt; data.kg,
  
          domainLowerBoundFn: (day_kg data, _) =&gt; data.domainLower,
  
          measureLowerBoundFn: (day_kg data, _) =&gt; data.measureLower,
          strokeWidthPxFn: (_, __) =&gt; 4,
          data: myFakeDesktopData,
        ),
  
  
      ];
    }
  
  }
  
  class day_kg {
    final int date;
    final int kg;
  
    final int domainUpper = 100;
    final int domainLower = 0;
  
    final int measureUpper = 100;
    final int measureLower = 0;
  
    day_kg(this.date, this.kg);
  }
  
  </code></pre>