An empty chart is displayed when the chart contains only one data point with the bar renderer

In order to display a data point, the bar renderer must calculate the width and height of the bar using the x and y axis data range, respectively. When there is only one data point (0, 10) in the data source, the data range of the x-axis is [0,0] and y-axis is [10,10]. With both data ranges being 0, an empty chart will be displayed. You can display a bar for the single data point chart in the following ways:

1. By explicitly set the data range for both x and y axis using the following methods:
   • IlvChart.getXAxis()
   • lvChart.getYAxis(int index)
   • IlvAxis.setDataRange(int min, int max)
   • IlvAxis.setDataRange(IlvDataInterval range)
   Note that the data point must be within the given data range.
2. By setting your own data range policy to the chart.
    

   chart.setDataRangePolicy (new IlvDefaultDataRangePolicy (){
      public IlvDataInterval computeDataRange(IlvChart chart,
           IlvAxis axis, IlvDataInterval retRange) {
        if( retRange != null && retRange.getLength() == 0 )
           // return your own data interval that contains the data point.
        else
          return super.computeDataRange( chart, axis, retRange );
      } 
   }