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.

The following example(s) require Flash Player 10 and the Adobe Flex 4 SDK. To download the Adobe Flash Builder 4 trial, see http://www.adobe.com/products/flex/. To download the latest nightly build of the Flex 4 SDK, see http://opensource.adobe.com/wiki/display/flexsdk/Download+Flex+4.
For more information on getting started with Flex 4 and Flash Builder 4, see the official Adobe Flex Team blog.

<?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:

<?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 4 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 4 SDK.

Tagged as: displayFormatFunction, extractValueFunction, Gumbo