Flex Examples » VGroup (Spark) http://blog.flexexamples.com Just a bunch of Adobe Flex Examples Wed, 26 Jan 2011 18:09:51 +0000 en hourly 1 Auto scrolling the contents of a VGroup container in Flex 4 http://blog.flexexamples.com/2009/11/02/auto-scrolling-the-contents-of-a-vgroup-container-in-flex-4/ http://blog.flexexamples.com/2009/11/02/auto-scrolling-the-contents-of-a-vgroup-container-in-flex-4/#comments Mon, 02 Nov 2009 23:50:34 +0000 Peter deHaan http://blog.flexexamples.com/?p=2136 The following example shows how you can tab through a series of Spark TextInput controls in Flex 4 and auto-scroll the VGroup container so that the currently focused text field has focus by using the fractionOfElementInView() method, getScrollPositionDeltaToElement() method, and verticalScrollPosition property.

Full code after the jump.

And a big thanks to The following example shows how you can tab through a series of Spark TextInput controls in Flex 4 and auto-scroll the VGroup container so that the currently focused text field has focus by using the fractionOfElementInView() method, getScrollPositionDeltaToElement() method, and verticalScrollPosition property.

Full code after the jump.

And a big thanks to Hans Muller for explaining this all to me.

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/2009/11/02/auto-scrolling-the-contents-of-a-vgroup-container-in-flex-4/ -->
<s:Application name="Spark_VerticalLayout_getScrollPositionDeltaToElement_test"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark">
 
    <fx:Script>
        <![CDATA[
            import mx.core.IVisualElement;
            import spark.layouts.VerticalLayout;
 
            protected function textinput_focusInHandler(evt:FocusEvent):void {
                var idx:int = vg.getElementIndex(evt.currentTarget as IVisualElement);
                var lay:VerticalLayout = vg.layout as VerticalLayout;
                if (lay.fractionOfElementInView(idx) < 1) {
                    lay.verticalScrollPosition += lay.getScrollPositionDeltaToElement(idx).y;
                }
            }
        ]]>
    </fx:Script>
 
    <s:Scroller id="scrllr"
            focusEnabled="false"
            hasFocusableChildren="true"
            height="100"
            horizontalCenter="0" verticalCenter="0">
        <s:VGroup id="vg"
                paddingLeft="10" paddingRight="10" paddingTop="10" paddingBottom="10">
            <s:TextInput text="One" focusIn="textinput_focusInHandler(event);" />
            <s:TextInput text="Two" focusIn="textinput_focusInHandler(event);" />
            <s:TextInput text="Three" focusIn="textinput_focusInHandler(event);" />
            <s:TextInput text="Four" focusIn="textinput_focusInHandler(event);" />
            <s:TextInput text="Five" focusIn="textinput_focusInHandler(event);" />
            <s:TextInput text="Six" focusIn="textinput_focusInHandler(event);" />
            <s:TextInput text="Seven" focusIn="textinput_focusInHandler(event);" />
            <s:TextInput text="Eight" focusIn="textinput_focusInHandler(event);" />
            <s:TextInput text="Nine" focusIn="textinput_focusInHandler(event);" />
        </s:VGroup>
    </s:Scroller>
 
</s:Application>

If you wanted to add a little scrolling animation (’cause who DOESN’T love animation!?), you could use an Animate with a SimpleMotionPath, as seen in the following example:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/11/02/auto-scrolling-the-contents-of-a-vgroup-container-in-flex-4/ -->
<s:Application name="Spark_VerticalLayout_getScrollPositionDeltaToElement_test"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark">
 
    <fx:Script>
        <![CDATA[
            import mx.core.IVisualElement;
            import spark.layouts.VerticalLayout;
 
            protected function textinput_focusInHandler(evt:FocusEvent):void {
                var idx:int = vg.getElementIndex(evt.currentTarget as IVisualElement);
                var lay:VerticalLayout = vg.layout as VerticalLayout;
                if (lay.fractionOfElementInView(idx) < 1) {
                    pth.valueBy = lay.getScrollPositionDeltaToElement(idx).y;
                    anim.play([lay]);
                }
            }
        ]]>
    </fx:Script>
 
    <fx:Declarations>
        <s:Animate id="anim" duration="500">
            <s:motionPaths>
                <s:SimpleMotionPath id="pth" property="verticalScrollPosition" />
            </s:motionPaths>
        </s:Animate>
    </fx:Declarations>
 
    <s:Scroller id="scrllr"
            focusEnabled="false"
            hasFocusableChildren="true"
            height="100"
            horizontalCenter="0" verticalCenter="0">
        <s:VGroup id="vg"
                paddingLeft="10" paddingRight="10" paddingTop="10" paddingBottom="10">
            <s:TextInput text="One" focusIn="textinput_focusInHandler(event);" />
            <s:TextInput text="Two" focusIn="textinput_focusInHandler(event);" />
            <s:TextInput text="Three" focusIn="textinput_focusInHandler(event);" />
            <s:TextInput text="Four" focusIn="textinput_focusInHandler(event);" />
            <s:TextInput text="Five" focusIn="textinput_focusInHandler(event);" />
            <s:TextInput text="Six" focusIn="textinput_focusInHandler(event);" />
            <s:TextInput text="Seven" focusIn="textinput_focusInHandler(event);" />
            <s:TextInput text="Eight" focusIn="textinput_focusInHandler(event);" />
            <s:TextInput text="Nine" focusIn="textinput_focusInHandler(event);" />
        </s:VGroup>
    </s:Scroller>
 
</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.

 
]]> http://blog.flexexamples.com/2009/11/02/auto-scrolling-the-contents-of-a-vgroup-container-in-flex-4/feed/ 9 Determining how much of an item is visible in a scrolling VGroup container in Flex 4 http://blog.flexexamples.com/2009/10/31/determining-how-much-of-an-item-is-visible-in-a-scrolling-vgroup-container-in-flex-4/ http://blog.flexexamples.com/2009/10/31/determining-how-much-of-an-item-is-visible-in-a-scrolling-vgroup-container-in-flex-4/#comments Sat, 31 Oct 2009 14:45:06 +0000 Peter deHaan http://blog.flexexamples.com/?p=2122 In a previous example, “Determining the first and last visible item in a scrolling VGroup container in Flex 4″, we saw how you could determine the first and last item in a Spark VGroup container’s view by using the firstIndexInView and lastIndexInView properties on the VGroup container’s layout property.

The following example shows how [...]]]> In a previous example, “Determining the first and last visible item in a scrolling VGroup container in Flex 4″, we saw how you could determine the first and last item in a Spark VGroup container’s view by using the firstIndexInView and lastIndexInView properties on the VGroup container’s layout property.

The following example shows how you can determine how much of an item is visible in a scrolling VGroup container in Flex 4 by using the fractionOfElementInView() method.

Full code after the jump.

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/2009/10/31/determining-how-much-of-an-item-is-visible-in-a-scrolling-vgroup-container-in-flex-4/ -->
<s:Application name="Spark_VGroup_layout_fractionOfElementInView_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[
            import spark.layouts.VerticalLayout;
 
            private function init():void {
                scrllr.verticalScrollBar.addEventListener("valueCommit", scrllrVSB_change);
                scrllrVSB_change(null);
            }
 
            private function scrllrVSB_change(evt:Event):void {
                var vLay:VerticalLayout = vgr.layout as VerticalLayout;
                var fIndex:int = vLay.firstIndexInView;
                var fObj:Object = vgr.getElementAt(fIndex);
                var lIndex:int = vLay.lastIndexInView;
                var lObj:Object = vgr.getElementAt(lIndex);
 
                lbl1.text = vLay.fractionOfElementInView(fIndex).toFixed(2) + " (" + fObj.label + ")";
                lbl2.text = vLay.fractionOfElementInView(lIndex).toFixed(2) + " (" + lObj.label + ")";
            }
        ]]>
    </fx:Script>
 
    <s:Panel title="Spark Panel"
            horizontalCenter="0" verticalCenter="0">
        <s:Scroller id="scrllr"
                width="300" height="100"
                creationComplete="init();">
            <s:VGroup id="vgr"
                    paddingLeft="5" paddingRight="5" paddingTop="5" paddingBottom="5">
                <s:Button id="ch1" label="One" width="100%" />
                <s:Button id="ch2" label="Two" width="100%" />
                <s:Button id="ch3" label="Three" width="100%" />
                <s:Button id="ch4" label="Four" width="100%" />
                <s:Button id="ch5" label="Five" width="100%" />
                <s:Button id="ch6" label="Six" width="100%" />
                <s:Button id="ch7" label="Seven" width="100%" />
                <s:Button id="ch8" label="Eight" width="100%" />
                <s:Button id="ch9" label="Nine" width="100%" />
            </s:VGroup>
        </s:Scroller>
        <s:controlBarContent>
            <mx:Form styleName="plain" backgroundAlpha="0.0">
                <mx:FormItem label="firstIndexInView:">
                    <s:Label id="lbl1" />
                </mx:FormItem>
                <mx:FormItem label="lastIndexInView:">
                    <s:Label id="lbl2" />
                </mx:FormItem>
            </mx:Form>
        </s:controlBarContent>
    </s:Panel>
 
</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.

 
]]> http://blog.flexexamples.com/2009/10/31/determining-how-much-of-an-item-is-visible-in-a-scrolling-vgroup-container-in-flex-4/feed/ 2 Determining the first and last visible item in a scrolling VGroup container in Flex 4 http://blog.flexexamples.com/2009/10/30/determining-the-first-and-last-visible-item-in-a-scrolling-vgroup-container-in-flex-4/ http://blog.flexexamples.com/2009/10/30/determining-the-first-and-last-visible-item-in-a-scrolling-vgroup-container-in-flex-4/#comments Fri, 30 Oct 2009 14:29:57 +0000 Peter deHaan http://blog.flexexamples.com/?p=2119 The following example shows how you can determine the first and last item in a Spark VGroup container’s view by using the firstIndexInView and lastIndexInView properties on the VGroup container’s layout property.

Full code after the jump.

<?xml version="1.0" encoding="utf-8"?> <!-- http://blog.flexexamples.com/2009/10/30/determining-the-first-and-last-visible-item-in-a-scrolling-vgroup-container-in-flex-4/ --> <s:Application name="Spark_VGroup_firstIndexInView_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[ import spark.layouts.VerticalLayout;   [...]]]> The following example shows how you can determine the first and last item in a Spark VGroup container’s view by using the firstIndexInView and lastIndexInView properties on the VGroup container’s layout property.

Full code after the jump.

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/2009/10/30/determining-the-first-and-last-visible-item-in-a-scrolling-vgroup-container-in-flex-4/ -->
<s:Application name="Spark_VGroup_firstIndexInView_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[
            import spark.layouts.VerticalLayout;
 
            private function init():void {
                scrllr.verticalScrollBar.addEventListener("valueCommit", scrllrVSB_change);
                scrllrVSB_change(null);
            }
 
            private function scrllrVSB_change(evt:Event):void {
                var fIndex:int = VerticalLayout(vgr.layout).firstIndexInView;
                var fObj:Object = vgr.getElementAt(fIndex);
                var lIndex:int = VerticalLayout(vgr.layout).lastIndexInView;
                var lObj:Object = vgr.getElementAt(lIndex);
 
                lbl1.text = fIndex.toString() + " (" + fObj.label + ")";
                lbl2.text = lIndex.toString() + " (" + lObj.label + ")";
            }
        ]]>
    </fx:Script>
 
    <s:Panel title="Spark Panel"
            horizontalCenter="0" verticalCenter="0">
        <s:Scroller id="scrllr"
                width="300" height="100"
                creationComplete="init();">
            <s:VGroup id="vgr"
                    paddingLeft="5" paddingRight="5" paddingTop="5" paddingBottom="5">
                <s:Button id="ch1" label="One" width="100%" />
                <s:Button id="ch2" label="Two" width="100%" />
                <s:Button id="ch3" label="Three" width="100%" />
                <s:Button id="ch4" label="Four" width="100%" />
                <s:Button id="ch5" label="Five" width="100%" />
                <s:Button id="ch6" label="Six" width="100%" />
                <s:Button id="ch7" label="Seven" width="100%" />
                <s:Button id="ch8" label="Eight" width="100%" />
                <s:Button id="ch9" label="Nine" width="100%" />
            </s:VGroup>
        </s:Scroller>
        <s:controlBarContent>
            <mx:Form styleName="plain" backgroundAlpha="0.0">
                <mx:FormItem label="firstIndexInView:">
                    <s:Label id="lbl1" />
                </mx:FormItem>
                <mx:FormItem label="lastIndexInView:">
                    <s:Label id="lbl2" />
                </mx:FormItem>
            </mx:Form>
        </s:controlBarContent>
    </s:Panel>
 
</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.

 
]]> http://blog.flexexamples.com/2009/10/30/determining-the-first-and-last-visible-item-in-a-scrolling-vgroup-container-in-flex-4/feed/ 4 Toggling variable row heights on a Spark VGroup container in Flex 4 http://blog.flexexamples.com/2009/10/02/toggling-variable-row-heights-on-a-spark-vgroup-container-in-flex-4/ http://blog.flexexamples.com/2009/10/02/toggling-variable-row-heights-on-a-spark-vgroup-container-in-flex-4/#comments Fri, 02 Oct 2009 15:26:00 +0000 Peter deHaan http://blog.flexexamples.com/?p=1961 The following example shows how you can toggle variable item/row heights on a Spark VGroup container in Flex 4 by setting the Boolean variableRowHeight property.

Full code after the jump.

<?xml version="1.0" encoding="utf-8"?> <!-- http://blog.flexexamples.com/2009/10/02/toggling-variable-row-heights-on-a-spark-vgroup-container-in-flex-4/ --> <s:Application name="Spark_VGroup_variableRowHeight_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"> <s:controlBarContent> <s:CheckBox id="chckBx" label="variableRowHeight" selected="true" /> </s:controlBarContent>   <s:VGroup id="vGr" variableRowHeight="{chckBx.selected}" width="200" horizontalCenter="0" [...]]]> The following example shows how you can toggle variable item/row heights on a Spark VGroup container in Flex 4 by setting the Boolean variableRowHeight property.

Full code after the jump.

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/2009/10/02/toggling-variable-row-heights-on-a-spark-vgroup-container-in-flex-4/ -->
<s:Application name="Spark_VGroup_variableRowHeight_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">
    <s:controlBarContent>
        <s:CheckBox id="chckBx" label="variableRowHeight" selected="true" />
    </s:controlBarContent>
 
    <s:VGroup id="vGr"
            variableRowHeight="{chckBx.selected}"
            width="200"
            horizontalCenter="0" verticalCenter="0">
        <s:Border id="brdr1"
                backgroundColor="red"
                width="100%" height="30">
            <s:Label text="{brdr1.width}x{brdr1.height}"
                    horizontalCenter="0" verticalCenter="0" />
        </s:Border>
        <s:Border id="brdr2"
                backgroundColor="haloOrange"
                width="100%" height="60">
            <s:Label text="{brdr2.width}x{brdr2.height}"
                    horizontalCenter="0" verticalCenter="0" />
        </s:Border>
        <s:Border id="brdr3"
                backgroundColor="yellow"
                width="100%" height="20">
            <s:Label text="{brdr3.width}x{brdr3.height}"
                    horizontalCenter="0" verticalCenter="0" />
        </s:Border>
        <s:Border id="brdr4"
                backgroundColor="haloGreen"
                width="100%" height="90">
            <s:Label text="{brdr4.width}x{brdr4.height}"
                    horizontalCenter="0" verticalCenter="0" />
        </s:Border>
        <s:Border id="brdr5"
                backgroundColor="haloBlue"
                width="100%" height="40">
            <s:Label text="{brdr5.width}x{brdr5.height}"
                    horizontalCenter="0" verticalCenter="0" />
        </s:Border>
    </s:VGroup>
 
</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.

 
]]> http://blog.flexexamples.com/2009/10/02/toggling-variable-row-heights-on-a-spark-vgroup-container-in-flex-4/feed/ 1 Setting the requested row count on a Spark VGroup container in Flex 4 http://blog.flexexamples.com/2009/09/10/setting-the-requested-row-count-on-a-spark-vgroup-container-in-flex-4/ http://blog.flexexamples.com/2009/09/10/setting-the-requested-row-count-on-a-spark-vgroup-container-in-flex-4/#comments Fri, 11 Sep 2009 06:59:56 +0000 Peter deHaan http://blog.flexexamples.com/?p=1955 The following example shows how you can set the requested row count on a Spark VGroup container in Flex 4 by setting the requestedRowCount property.

Full code after the jump.

<?xml version="1.0" encoding="utf-8"?> <!-- http://blog.flexexamples.com/2009/09/10/setting-the-requested-row-count-on-a-spark-vgroup-container-in-flex-4/ --> <s:Application name="Spark_VGroup_requestedRowCount_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"> <s:controlBarContent> <mx:Form> <mx:FormItem label="requestedRowCount:"> <s:HSlider id="sldr" minimum="0" maximum="7" value="{vGr.numElements}" /> </mx:FormItem> </mx:Form> </s:controlBarContent> [...]]]> The following example shows how you can set the requested row count on a Spark VGroup container in Flex 4 by setting the requestedRowCount property.

Full code after the jump.

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/2009/09/10/setting-the-requested-row-count-on-a-spark-vgroup-container-in-flex-4/ -->
<s:Application name="Spark_VGroup_requestedRowCount_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">
    <s:controlBarContent>
        <mx:Form>
            <mx:FormItem label="requestedRowCount:">
                <s:HSlider id="sldr"
                        minimum="0"
                        maximum="7"
                        value="{vGr.numElements}" />
            </mx:FormItem>
        </mx:Form>
    </s:controlBarContent>
 
    <s:Panel id="pnl"
            title="rowCount={vGr.rowCount}"
            width="250"
            horizontalCenter="0" verticalCenter="0">
        <s:VGroup id="vGr"
                requestedRowCount="{sldr.value}"
                clipAndEnableScrolling="true"
                width="100%">
            <s:Border backgroundColor="red" width="100%" height="30" />
            <s:Border backgroundColor="haloOrange" width="100%" height="30" />
            <s:Border backgroundColor="yellow" width="100%" height="30" />
            <s:Border backgroundColor="haloGreen" width="100%" height="30" />
            <s:Border backgroundColor="haloBlue" width="100%" height="30" />
        </s:VGroup>
        <s:controlBarContent>
            <mx:Form styleName="plain" backgroundAlpha="0.0">
                <mx:FormItem label="firstIndexInView:">
                    <s:Label text="{vGr.firstIndexInView}" />
                </mx:FormItem>
                <mx:FormItem label="lastIndexInView:">
                    <s:Label text="{vGr.lastIndexInView}" />
                </mx:FormItem>
            </mx:Form>
        </s:controlBarContent>
    </s:Panel>
 
</s:Application>

You can also set the requestedRowCount property using ActionScript, as seen in the following example:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/09/10/setting-the-requested-row-count-on-a-spark-vgroup-container-in-flex-4/ -->
<s:Application name="Spark_VGroup_requestedRowCount_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">
    <s:controlBarContent>
        <mx:Form>
            <mx:FormItem label="requestedRowCount:">
                <s:HSlider id="sldr"
                        minimum="0"
                        maximum="7"
                        value="{vGr.numElements}"
                        change="sldr_change(event);"/>
            </mx:FormItem>
        </mx:Form>
    </s:controlBarContent>
 
    <fx:Script>
        <![CDATA[
            protected function sldr_change(evt:Event):void {
                vGr.requestedRowCount = sldr.value;
            }
        ]]>
    </fx:Script>
 
    <s:Panel id="pnl"
            title="rowCount={vGr.rowCount}"
            width="250"
            horizontalCenter="0" verticalCenter="0">
        <s:VGroup id="vGr"
                clipAndEnableScrolling="true"
                width="100%">
            <s:Border backgroundColor="red" width="100%" height="30" />
            <s:Border backgroundColor="haloOrange" width="100%" height="30" />
            <s:Border backgroundColor="yellow" width="100%" height="30" />
            <s:Border backgroundColor="haloGreen" width="100%" height="30" />
            <s:Border backgroundColor="haloBlue" width="100%" height="30" />
        </s:VGroup>
        <s:controlBarContent>
            <mx:Form styleName="plain" backgroundAlpha="0.0">
                <mx:FormItem label="firstIndexInView:">
                    <s:Label text="{vGr.firstIndexInView}" />
                </mx:FormItem>
                <mx:FormItem label="lastIndexInView:">
                    <s:Label text="{vGr.lastIndexInView}" />
                </mx:FormItem>
            </mx:Form>
        </s:controlBarContent>
    </s:Panel>
 
</s:Application>

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/2009/09/10/setting-the-requested-row-count-on-a-spark-vgroup-container-in-flex-4/ -->
<s:Application name="Spark_VGroup_requestedRowCount_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 mx.containers.Form;
            import mx.containers.FormItem;
            import mx.core.FlexGlobals;
 
            import spark.components.Border;
            import spark.components.HSlider;
            import spark.components.Label;
            import spark.components.Panel;
            import spark.components.VGroup;
 
            protected var pnl:Panel;
            protected var sldr:HSlider;
            protected var vGr:VGroup;
            protected var firstIndexLabel:Label;
            protected var lastIndexLabel:Label;
 
            private function init():void {
                sldr = new HSlider();
                sldr.minimum = 0;
                sldr.maximum = 7;
                sldr.addEventListener(Event.CHANGE, sldr_change);
 
                var formItem:FormItem = new FormItem();
                formItem.label = "requestedRowCount:";
                formItem.addElement(sldr);
 
                var form1:Form = new Form();
                form1.addElement(formItem);
 
                Application(FlexGlobals.topLevelApplication).controlBarContent = [form1];
 
                var brdr1:Border = new Border();
                brdr1.setStyle("backgroundColor", "red");
                brdr1.percentWidth = 100;
                brdr1.height = 30;
 
                var brdr2:Border = new Border();
                brdr2.setStyle("backgroundColor", "haloOrange");
                brdr2.percentWidth = 100;
                brdr2.height = 30;
 
                var brdr3:Border = new Border();
                brdr3.setStyle("backgroundColor", "yellow");
                brdr3.percentWidth = 100;
                brdr3.height = 30;
 
                var brdr4:Border = new Border();
                brdr4.setStyle("backgroundColor", "haloGreen");
                brdr4.percentWidth = 100;
                brdr4.height = 30;
 
                var brdr5:Border = new Border();
                brdr5.setStyle("backgroundColor", "haloBlue");
                brdr5.percentWidth = 100;
                brdr5.height = 30;
 
                vGr = new VGroup();
                vGr.clipAndEnableScrolling = true;
                vGr.percentWidth = 100;
                vGr.addElement(brdr1);
                vGr.addElement(brdr2);
                vGr.addElement(brdr3);
                vGr.addElement(brdr4);
                vGr.addElement(brdr5);
 
                firstIndexLabel = new Label();
 
                lastIndexLabel = new Label();
 
                var formItem1:FormItem = new FormItem();
                formItem1.label = "firstIndexInView:";
                formItem1.addElement(firstIndexLabel);
 
                var formItem2:FormItem = new FormItem();
                formItem2.label = "lastIndexInView:";
                formItem2.addElement(lastIndexLabel);
 
                var form2:Form = new Form();
                form2.styleName = "plain";
                form2.setStyle("backgroundAlpha", 0.0);
                form2.addElement(formItem1);
                form2.addElement(formItem2);
 
                pnl = new Panel();
                pnl.width = 250;
                pnl.horizontalCenter = 0;
                pnl.verticalCenter = 0;
                pnl.controlBarContent = [form2];
                pnl.addElement(vGr);
                addElement(pnl);
 
                callLater(updateLabels);
            }
 
            protected function sldr_change(evt:Event):void {
                vGr.requestedRowCount = sldr.value;
                callLater(updateLabels);
            }
 
            protected function updateLabels():void {
                pnl.title = "rowCount=" + vGr.rowCount.toString();
                firstIndexLabel.text = vGr.firstIndexInView.toString();
                lastIndexLabel.text = vGr.lastIndexInView.toString();
            }
        ]]>
    </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.

 
]]> http://blog.flexexamples.com/2009/09/10/setting-the-requested-row-count-on-a-spark-vgroup-container-in-flex-4/feed/ 0