Setting a roll over open delay on a Spark DropDownList control in Flex 4

The following example shows how you can set a roll over open delay on a Spark DropDownList control in Flex 4 by extending the DropDownList control, accessing the protected DropDownController object and setting the rollOverOpenDelay property.

The following example(s) require Flash Player 10 and the Adobe Flex 4 SDK. To download the Adobe Flash Builder 4 trial, see www.adobe.com/products/flex/. To download the latest nightly build of the Flex 4 SDK, see 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/2010/02/03/setting-a-roll-over-open-delay-on-a-spark-dropdownlist-control-in-flex-4/ -->
<s:Application name="Spark_DropDownList_dropDownController_rollOverOpenDelay_test"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        xmlns:mx="library://ns.adobe.com/flex/mx"
        xmlns:local="*">
    <s:layout>
        <s:VerticalLayout horizontalAlign="center" paddingTop="20" />
    </s:layout>
    <s:controlBarContent>
        <mx:Form>
            <mx:FormItem label="rollOverOpenDelay:" direction="horizontal">
                <s:HSlider id="sl"
                        minimum="100" maximum="1500"
                        value="200"
                        change="init();" />
                <s:Label text="{sl.value} ms" />
            </mx:FormItem>
        </mx:Form>
    </s:controlBarContent>
 
    <fx:Script>
        <![CDATA[
            import spark.components.supportClasses.DropDownController;
 
            private function init():void {
                var con:DropDownController = dropper.controller;
                con.rollOverOpenDelay = sl.value;
            }
        ]]>
    </fx:Script>
 
    <local:MyDropDownList id="dropper"
            prompt="Roll over to open..."
            width="200"
            creationComplete="init();">
        <local:dataProvider>
            <s:ArrayList source="[Red,Orange,Yellow,Green,Blue,Purple]" />
        </local:dataProvider>
    </local:MyDropDownList>
 
</s:Application>

And the custom DropDownList, MyDropDownList.as, is as follows:

/** http://blog.flexexamples.com/2010/02/03/setting-a-roll-over-open-delay-on-a-spark-dropdownlist-control-in-flex-4/ */
package {
    import spark.components.DropDownList;
    import spark.components.supportClasses.DropDownController;
 
    public class MyDropDownList extends DropDownList {
        public function MyDropDownList() {
            super();
        }
 
        public function get controller():DropDownController {
            return super.dropDownController;
        }
 
        public function set controller(value:DropDownController):void {
            super.dropDownController = value;
        }
    }
}

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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.

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