03
Apr
08

Setting the horizontal scroll position in the HorizontalList control in Flex

The following example shows how you can scroll the Flex HorizontalList control by setting the horizontalScrollPosition property.

Full code after the jump.

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/04/03/scrolling-the-horizontallist-control-in-flex/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:Script>
        <![CDATA[
            import mx.events.SliderEvent;

            private function prev():void {
                var pos:int = hList.horizontalScrollPosition-1;
                var min:int = 0;
                var value:int = Math.max(min, pos);
                hList.horizontalScrollPosition = value;
            }

            private function next():void {
                var pos:int = hList.horizontalScrollPosition+1;
                var max:int = hList.maxHorizontalScrollPosition;
                var value:int = Math.min(pos, max);
                hList.horizontalScrollPosition = value;
            }

            private function slider_change(evt:SliderEvent):void {
                hList.horizontalScrollPosition = evt.value;
            }
        ]]>
    </mx:Script>

    <mx:Array id="arr">
        <mx:Object lbl="Illustrator" src="ai_appicon-tn.gif" />
        <mx:Object lbl="Adobe AIR" src="air_appicon-tn.gif" />
        <mx:Object lbl="ColdFusion" src="cf_appicon-tn.gif" />
        <mx:Object lbl="Dreamweaver" src="dw_appicon-tn.gif" />
        <mx:Object lbl="Flash" src="fl_appicon-tn.gif" />
        <mx:Object lbl="Flash Player" src="fl_player_appicon-tn.gif" />
        <mx:Object lbl="Fireworks" src="fw_appicon-tn.gif" />
        <mx:Object lbl="Flex" src="fx_appicon-tn.gif" />
        <mx:Object lbl="Lightroom" src="lr_appicon-tn.gif" />
        <mx:Object lbl="Photoshop" src="ps_appicon-tn.gif" />
    </mx:Array>

    <mx:Panel styleName="opaquePanel">
        <mx:HorizontalList id="hList"
                dataProvider="{arr}"
                itemRenderer="HorizontalListItemRenderer"
                verticalScrollPolicy="off"
                horizontalScrollPolicy="off"
                columnWidth="100"
                columnCount="4"
                rowHeight="100"
                rowCount="1"
                borderSkin="{null}" />
        <mx:ControlBar>
            <mx:Button label="Previous" click="prev();" />
            <mx:HSlider id="slider"
                    minimum="0"
                    maximum="{hList.maxHorizontalScrollPosition}"
                    value="{hList.horizontalScrollPosition}"
                    liveDragging="true"
                    snapInterval="1"
                    tickInterval="1"
                    showDataTip="false"
                    width="100%"
                    change="slider_change(event);" />
            <mx:Button label="Next" click="next();" />
        </mx:ControlBar>
    </mx:Panel>

</mx:Application>

View HorizontalListItemRenderer.mxml

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/04/03/scrolling-the-horizontallist-control-in-flex/ -->
<mx:Canvas xmlns:mx="http://www.adobe.com/2006/mxml"
        styleName="plain">

    <mx:Image source="{data.src}"
            horizontalCenter="0"
            verticalCenter="0" />
    <mx:Label text="{data.lbl}"
            fontWeight="bold"
            horizontalCenter="0"
            bottom="0" />

</mx:Canvas>

View source is enabled in the following example.


9 Responses to “Setting the horizontal scroll position in the HorizontalList control in Flex”


  1. 1 Raul Riera Apr 4th, 2008 at 10:56 am

    Again, I love this site.. so great that you post this kind of simple yet undergrated thins.

  2. 2 Deb Apr 15th, 2008 at 2:34 am

    Hi! Thanks for providing that code…its really useful. Waiting for your next post.

  3. 3 Keith May 8th, 2008 at 8:09 am

    Awesome site and great post. Helped me greatly. Anyone have an idea on how to apply effects as you transition between list items?

  4. 4 Brian P Jul 8th, 2008 at 5:47 pm

    Hello, Thanks for the great info on your site.

    Question on this example: Is this something that is easily set to use the tween class to slide from image to image, instead of just jumping?

  5. 5 Chris Oct 30th, 2008 at 8:28 am

    Great example, it really helped me extend my gallery. Is there a way to add effects to transition between items on a HorizontalList?

  6. 6 Lynn Nov 11th, 2008 at 8:05 am

    A very cool example! Is it possible to have the sliding effect within the horizontal list instead of using the slider and buttons?

    Thanks=)

  7. 7 Taniguchi Toshio, J. May 6th, 2009 at 10:51 pm

    I agree with Raul! This is one of the greatest reference for new Flex programmers.
    As usual, another great sample!

    Thanks Peter :)

  8. 8 Taniguchi Toshio, J. May 8th, 2009 at 2:02 pm

    Hi,
    maybe this is the wrong topic to place my post but I couldn’t find anything similar to my prob.
    I’m just starting with Flex Builder 3 and after reading a couple of books, I’m trying to build my own RIA. Everything was wonderful and I was happy with the results until I got stuck with a Canvas problem. I got a canvas(A) within another canvas(B) which B can be scaled using a Slider. It worked fine but the thing is, to center the scale of B relative to A it making me mad. I’ve been searching the net for a week and I couldn’t find anything to help me figure it out. My code works but when I try to slide from 200% to 10%, to position from B gets all mess up.
    My code: A = _wrap / B = _doc
    /* ———————– */
    private function alignDoc():void {

    if(_doc.width > _wrap.width){
    _doc.x = 30;
    _wrap.horizontalScrollBar.setStyle(”thumbWidth”, 100);
    _wrap.horizontalScrollPosition = _wrap.horizontalScrollBar.width / 2;
    }
    if(_doc.height > _wrap.height){
    _doc.y = 30;
    _wrap.verticalScrollPosition = _wrap.verticalScrollBar.height / 2;
    }

    if(_doc.width

  9. 9 sean Jun 10th, 2009 at 4:15 pm

    Thank you for sharing! it works :)

Leave a Reply

This blog is terrible at eating HTML tags. If you plan on posting code/XML, please escape your "<" characters as "&lt;" and your ">" characters as "&gt;".




Badge Farm

  • Powered by Redoable 1.2
  • Cornify
  • Feeds burnt by Feedburner
  • Feed