Bar Chart

In depth guide to the Bar Chart Widget.

A Bar Chart is the most common visual representation of numeric data as Vertical or Horizontal Bars.

To draw a Bar Chart, we will use the BarChart widget. Let's use the widget to draw a simple bar chart with only one Bar.

Code Sample

...
import 'package:chart_it/chart_it.dart';

class TestBarCharts extends StatefulWidget {
  const TestBarCharts({Key? key}) : super(key: key);

  @override
  State<TestBarCharts> createState() => _TestBarChartsState();
}

class _TestBarChartsState extends State<TestBarCharts> {
  @override
  Widget build(BuildContext context) {
    return BarChart(
      data: BarSeries(
        barData: <BarGroup>[
          SimpleBar(
            xValue: 1,
            yValue: BarData(yValue: 27),
          ),
        ],
      ),
    );
  }
}

Result

Before moving forward, let's understand the above example code.

The widget BarChart requires a mandatory field data of type BarSeries. This is a series class that ensures that any data provided to this series should be represented as a BarChart.

The BarSeries requires barData which is a List of BarGroup. You can see that we have provided a class SimpleBar which extends a BarGroup. BarGroups define how your data will be represented as Bars on the chart. We will go into further details for BarGroup later.

Finally, our SimpleBar takes a yValue of class BarData which also requires a yValue which is a numeric value, representing the data value for this SimpleBar. You may have some questions about the structuring complexity of these data classes for the widget, just to draw a simple bar. But it will be clear behind this approach in later sections.