LineChart data tip won't display with single data point? - apache-flex

Question

In Flex 3, I have a line chart.
My data provider for the line chart contains only one item.
When I draw the line chart, it plots the point. But it doesn't show the data tip.
It works if more than one item is present in dataprovider.
How can I make a data tip visible for line chart with dataprovider containing a single data item?

Answer 1

Use PlotSeries instead of LineSeries when you only have one point. You will get a nice round point with its dataTip. How to do it exactly depends on how your data is built - if the data doesn't change after being assigned to the dataProvider, you can choose which type of series to use at that moment.

Answer 2

try the following code,
in actionscript,
lineSeries.setStyle("itemRenderer", new ClassFactory(mx.charts.renderers.CircleItemRenderer));
in mxml,
<mx:LineSeries yField="Y" itemRenderer="mx.charts.renderers.CircleItemRenderer" xField="X" dataProvider="{lineDataProvider}">

Answer 3

There is a workaround to show the datatip. We need to add ROLL_OVER and ROLL_OUT mouse event listeners to the line series which has single datapoint.
<?xml version="1.0"?>
<!-- Simple example to demonstrate the LineChart and AreaChart controls. -->
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx">
<fx:Script>
<![CDATA[
import mx.charts.HitData;
import mx.charts.renderers.*;
import mx.charts.series.items.LineSeriesItem;
import mx.collections.ArrayCollection;
[Bindable]
private var expensesAC:ArrayCollection = new ArrayCollection( [
{ Month: "Jan", Profit: 2000 } ]);
private function lineseriesRollOverHandler(event:MouseEvent):void
{
linechart.showAllDataTips = true;
}
private function lineserieRollOutHandler(event:MouseEvent):void
{
linechart.showAllDataTips = false;
}
private function dataTipFunction(hitData:HitData):String
{
if(hitData && hitData.item)
{
var s:String = "";
if(hitData.element is LineSeries)
{
if(expensesAC.length <=1)
hitData.x = 56;
var lsi:LineSeriesItem = hitData.chartItem as LineSeriesItem;
if(lsi == null)
return "";
s += "<b>" + (hitData.element as LineSeries).displayName + "</b><br />";
s += lsi.xValue + "<br />";
s += lsi.yNumber;
}
return s;
}
return "";
}
]]>
</fx:Script>
<fx:Declarations>
</fx:Declarations>
<mx:Panel width="100%" height="100%" layout="horizontal" title="Single point LineChart Example">
<mx:LineChart id="linechart" width="45%" height="100%" dataProvider="{expensesAC}"
paddingLeft="5" paddingRight="5" showDataTips="true" dataTipFunction="dataTipFunction">
<mx:horizontalAxis>
<mx:CategoryAxis categoryField="Month"/>
</mx:horizontalAxis>
<mx:series>
<mx:LineSeries displayName="Profit" form="curve"
itemRenderer="mx.charts.renderers.CircleItemRenderer"
legendMarkerRenderer="mx.charts.renderers.BoxItemRenderer"
rollOut="lineserieRollOutHandler(event)"
rollOver="lineseriesRollOverHandler(event)" yField="Profit"/>
</mx:series>
</mx:LineChart>
<mx:Legend dataProvider="{linechart}"/>
</mx:Panel>
</s:Application>