Why shouldn't all lists virtualise? If the dataProvider of a list has a
large or very large number of items, doesn't it make sense to only create
enough itemRenderers for the visible area?
On Sat, Feb 15, 2014 at 9:30 AM, Alex Harui <aha...@adobe.com> wrote:
>
>
> Yep, didn't notice you are using TileLayout. I'm pretty sure it doesn't
> virtualize
>
>
> From: Chris Velevitch <chris.velevi...@gmail.com>
> Reply-To: "flexcoders@yahoogroups.com" <flexcoders@yahoogroups.com>
> Date: Friday, February 14, 2014 2:26 AM
> To: "flexcoders@yahoogroups.com" <flexcoders@yahoogroups.com>
> Subject: Re: [flexcoders] Whay are too many itemrenderers being created?
>
>
>
> 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
>
>
>
>
>
--
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
