ChartView for Xamarin.Android: CategoricalAxis

When RadCartesianChartView visualizes CategoricalSeries, it needs an axis that can represent the different categories. The CategoricalAxis extends the base CartesianAxis class and is used to displays a range of categories. Categories are built depending on the Category value of each CategoricalDataPoint present in the owning CategoricalSeries chart series. The axis is divided into discrete slots and each data point is visualized in the slot corresponding to its categorical value.

The CategoricalAxis extends the base CartesianAxis class and is used to displays a range of categories. Categories are built depending on the Category value of each CategoricalDataPoint present in the owning CategoricalSeries chart series. The axis is divided into discrete slots and each data point is visualized in the slot corresponding to its categorical value.

Example

You can read from the Getting Started page how to define the MonthResult type and declare the initData() method.

After you create the method for initialization of sample data, you can create a RadCartesianChartView with LineSeries by adding the following code to the onCreate() method of your Activity.

InitData();

RadCartesianChartView chartView = new RadCartesianChartView(this);

LineSeries lineSeries = new LineSeries();
lineSeries.CategoryBinding = new MonthResultDataBinding ("Month");
lineSeries.ValueBinding = new MonthResultDataBinding ("Result");
lineSeries.Data = (Java.Lang.IIterable)this.monthResults;

chartView.Series.Add(lineSeries);

CategoricalAxis horizontalAxis = new CategoricalAxis();
chartView.HorizontalAxis = horizontalAxis;

LinearAxis verticalAxis = new LinearAxis();
chartView.VerticalAxis = verticalAxis;

ViewGroup rootView = (ViewGroup)FindViewById(Resource.Id.container);
rootView.AddView(chartView);

Here's the result:

Features

Plot Mode

The CategoricalAxis allows you to define how exactly the axis will be plotted on the viewport of the chart through its PlotMode property. The possible values are:

• AxisPlotMode.BetweenTicks: Points are plotted in the middle of the range, defined between each two ticks.
• AxisPlotMode.OnTicks: Points are plotted over each tick.
• AxisPlotMode.OnTicksPadded: Points are plotted over each tick with half a step padding applied on both ends of the axis.

Gap Length

Defines the distance (in logical units) between two adjacent categories. Default value is 0.3. For example if you have BarSeries, you can decrease the space between the bars from the different categories by setting the GapLength property to a value lower than 0.3.

Major Tick Interval

MajorTickInterval property defines the step at which major ticks are generated. The default and also minimum value is 1. This property also affects axis labels as they are generated on a per major tick basis. For example, if you don't want to display all ticks, but instead only half of them (display the first, third, fifth, etc. ticks), you should set the major tick interval to 2:

horizontalAxis.MajorTickInterval = 2;