Flex: How to add horizontal axes to a chart?

Question

I have a dynamically created chart and I need to add a horizontal and vertical axis in a script. I can't put the chart into MXML because I'm dynamically changing the chart type, deleting and creating a new chart. Therefore, the variable that I use to create the chart, an instance of chartBase, doesn't have either a horizontalAxis or verticalAxis. How do I assign to them if they don't exist? Should I be using a different type? The graphs I want to use are line, bar, and HLOC and/or candlestick.

Answer 1

I think you'll get better results by instantiating your chart as a proper type.

For example, in a component I have a skeleton lineChart setup in the mxml...

<mx:LineChart id="lineChart" dataProvider="{chartData}" dataTipFunction="dataTipFunction"
 width="100%"
 height="100%"
 showDataTips="true"
 />

... but you could create it as a variable and add it to the container. Then for the axis I determine the type I want and create and apply them, here's some code I use for the horizontal axis...

// Setup new horizontal axis.
switch (hAxisFieldsComboBox.selectedItem.dataType)
{
 case "Date":
  var hDtAxis:DateTimeAxis = new DateTimeAxis();
  hDtAxis.title = hAxisFieldsComboBox.selectedItem.label;
  hDtAxis.dataUnits = "days";
  hDtAxis.dataInterval = 1;
  hDtAxis.parseFunction = dateParser;
  lineChart.horizontalAxis = hDtAxis;
  break;
 case "Time":
  var hTAxis:DateTimeAxis = new DateTimeAxis();
  hTAxis.title = hAxisFieldsComboBox.selectedItem.label;
  hTAxis.dataInterval = 1;
  hTAxis.parseFunction = timeParser;
  lineChart.horizontalAxis = hTAxis;
  break;
 case "Number":
  var hLAxis:LinearAxis = new LinearAxis();
  hLAxis.title = hAxisFieldsComboBox.selectedItem.label;
  hLAxis.interval = 1;
  hLAxis.minimum = 0;
  lineChart.horizontalAxis = hLAxis;
  break;
 default:
  var hCatAxis:CategoryAxis = new CategoryAxis();
  hCatAxis.title = hAxisFieldsComboBox.selectedItem.label;
  hCatAxis.dataProvider = schemaUtil.aggregateAndSortCasesAC(chartData, vAxisFieldsComboBox.selectedItem.data, [hAxisFieldsComboBox.selectedItem.data]);
  hCatAxis.categoryField = hAxisFieldsComboBox.selectedItem.data;
  lineChart.horizontalAxis = hCatAxis;
}

Hope that helps.