That makes no difference. I did notice that <VerticalLayout/> always
virtualises regardless of whether useVirtualLayout is true or false.
It looks like <TileLayout/> never virtualises, so I suspect it's a bug, but
I haven't had a chance to look into how layouts work to confirm this.
On Fri, Feb 14, 2014 at 5:37 PM, Alex Harui <aha...@adobe.com> wrote:
>
>
> useVirtualLayout property?
>
> From: Chris Velevitch <chris.velevi...@gmail.com>
> Reply-To: "flexcoders@yahoogroups.com" <flexcoders@yahoogroups.com>
> Date: Thursday, February 13, 2014 7:34 PM
> To: "flexcoders@yahoogroups.com" <flexcoders@yahoogroups.com>
> Subject: [flexcoders] Whay are too many itemrenderers being created?
>
>
>
> I'm using Flex 4.11 with Air 4.0 to create a mobile app.
>
> I have a spark list with a custom mxml itemRenderer. Only 4 instances
> will be visible in the list. The dataprovider is initially empty.
>
> When I assign the array collection with an array of 147 items, I get 147
> traces on dataChange event and on the render event. I traced out the value
> of 'this' and I get 147 unique objects.
>
> I was under the impression that only 4 instances of the itemRenderer
> will be created and get reused as I scroll through the list.
>
> What have I overlooked?
>
> The list is defined as:-
>
> <s:List id="lImages" dataProvider="{imageList}" width="100%"
> height="100%" allowMultipleSelection="true"
> change="lImagesChange(event)" itemRenderer="PhotoThumbNail"
> doubleClickEnabled="true" doubleClick="showImage(event)">
> <s:layout>
> <s:TileLayout/>
> </s:layout>
> </s:List>
>
> and the itemRenderer is defined as:-
>
> <?xml version="1.0"?>
> <s:ItemRenderer
> xmlns:fx="http://ns.adobe.com/mxml/2009";
> xmlns:s="library://ns.adobe.com/flex/spark"
> dataChange="onDataChange(event)"
> render="onRender(event)"
> width="150" height="175"
> >
>
> <s:layout>
> <s:VerticalLayout/>
> </s:layout>
>
> <fx:Script><![CDATA[
> import DateUtils;
>
> import mx.events.FlexEvent;
>
> private function onDataChange(event:FlexEvent):void {
> trace(DateUtils.currentTime() + "PhotoThumbNail.onDataChange:
> dataChange event, index=" + itemIndex + ", this="+this);
> }
>
> private function onRender(event:Event):void {
> trace(DateUtils.currentTime() + "PhotoThumbNail.onRender;
> render event, index=" + itemIndex + ", this="+this);
> }
> ]]></fx:Script>
> <s:BitmapImage source="{data.image}" width="150" height="150"/>
> <s:Label text="{data.timestamp}" width="150"/>
>
> </s:ItemRenderer>
>
> --
>
>
> Chris
> --
> Chris Velevitch
> Manager - Adobe Platform Users Group, Sydney
> m: 0415 469 095
> www.apugs.org.au
>
> Adobe Platform Users Group, Sydney
> Topic: TBD
> Date: Monday, 28th February
> Details and RSVP on http://www.meetup.com/Sydney-Adobe-Platform-User-Group
>
>
>
>
>
--
Chris
--
Chris Velevitch
Manager - Adobe Platform Users Group, Sydney
m: 0415 469 095
www.apugs.org.au
Adobe Platform Users Group, Sydney
Topic: TBD
Date: Monday, 28th February
Details and RSVP on http://www.meetup.com/Sydney-Adobe-Platform-User-Group
