Creating an extract value function on a Spark NumericStepper control in Flex 4

The following example shows how you can set a display format function and extract value function on a Spark NumericStepper control in Flex 4 by setting the displayFormatFunction and extractValueFunction properties.

Full code after the jump.

To use the following code, you must have Flash Player 10 and a Flex Gumbo SDK installed in your Flex Builder 3. For more information on downloading and installing the Gumbo SDK into Flex Builder 3, see “Using the beta Gumbo SDK in Flex Builder 3″. To download the latest build of the Flex 4 SDK, see http://opensource.adobe.com/wiki/display/flexsdk/Download+Flex+4.

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/06/01/creating-an-extract-value-function-on-a-spark-numericstepper-control-in-flex-4/ -->
<s:Application name="Spark_NumericStepper_extractValueFunction_test"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        xmlns:mx="library://ns.adobe.com/flex/halo">

    <fx:Script>
        <![CDATA[
            private function displayFmtFunc(value:Number):String {
                return value + "mm";
            }

            private function extractValueFunc(value:String):Number {
                return parseInt(value);
            }
        ]]>
    </fx:Script>

    <s:NumericStepper id="numericStepper"
            minimum="0"
            maximum="100"
            displayFormatFunction="displayFmtFunc"
            extractValueFunction="extractValueFunc"
            horizontalCenter="0"
            verticalCenter="0" />

</s:Application>

View source is enabled in the following example.

Due to popular demand, here is the “same” example in a more ActionScript friendly format:

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/06/01/creating-an-extract-value-function-on-a-spark-numericstepper-control-in-flex-4/ -->
<s:Application name="Spark_NumericStepper_extractValueFunction_test"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        xmlns:mx="library://ns.adobe.com/flex/halo"
        initialize="init();">

    <fx:Script>
        <![CDATA[
            import spark.components.NumericStepper;

            private var numericStepper:NumericStepper;

            private function init():void {
                numericStepper = new NumericStepper();
                numericStepper.minimum = 0;
                numericStepper.maximum = 100;
                numericStepper.displayFormatFunction = displayFmtFunc;
                numericStepper.extractValueFunction = extractValueFunc;
                numericStepper.horizontalCenter = 0;
                numericStepper.verticalCenter = 0;
                addElement(numericStepper);
            }

            private function displayFmtFunc(value:Number):String {
                return value + "mm";
            }

            private function extractValueFunc(value:String):Number {
                return parseInt(value);
            }
        ]]>
    </fx:Script>

</s:Application>

This entry is based on a beta version of the Flex Gumbo SDK and therefore is very likely to change as development of the Flex SDK continues. The API can (and will) change causing examples to possibly not compile in newer versions of the Flex Gumbo SDK.

Tagged as: displayFormatFunction, extractValueFunction, Gumbo