useVirtualLayout property?
From: Chris Velevitch
<[email protected]<mailto:[email protected]>>
Reply-To: "[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>
Date: Thursday, February 13, 2014 7:34 PM
To: "[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>
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<http://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<http://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
