Load images using loader class and send the images in an arrayCollection

Question

I am facing a particular problem which I am unable to resolve. I am using ActionScript 3 with Robotlegs framework. I have to make a series of URL Requests in a command. Each URL gives an image. I am pushing these images into an ArrayCollection and then dispatching an event with this ArrayCollection as the payload. This ArrayCollection is sent to a view which uses an itemRenderer to display the images. I have checked that images are being loaded to the ArrayCollection but the images are not being displayed in the view.

This is what I have written in the command,

var arrayCollect:ArrayCollection = new ArrayCollection();
var my_loader:Loader = new Loader();

my_loader.load( new URLRequest( "http://www.joomlaworks.net/images/demos/galleries/abstract/7.jpg" ) );
arrayCollect.addItem(my_loader as Object );
my_loader.load( new URLRequest( "http://www.joomlaworks.net/images/demos/galleries/abstract/8.jpg" ) );
arrayCollect.addItem(my_loader as Object );

return arrayCollect;

Then the arrayCollect is being dispatched in a event as payload.

dispatch( new XYZEvent ( XYZEvent.LOAD_COMPLETE, arrayCollect ) );

In the view, I used an itemRenderer.

<s:List id="pqr"
dataProvider="{data}">

....
</s:List>

The images are not being displayed. I think the problem is that the data in the arrayCollection are objects of type 'loader'. So I tried to typecast it as a BitmapImage, but it did not resolve the issue.

Please help me resolve this.

Answer 1

Your problem is you didn't define a item renderer which could show your data. See http://help.adobe.com/en_US/Flex/4.0/UsingSDK/WS03d33b8076db57b9-23c04461124bbeca597-8000.html for creating custum itemrenderers.

Next: in your ArrayCollection you didn't create a new Loader. Meaning the ArrayCollection item 1 is pointing to the same laoder is item 2.

I added an example with 2 lists, one without a renderer an one with a custum renderer. I didn't use the loaders, but of course you could create a renderer which add a laoder to teh display instead of using a Flex image component.

Main application:

<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009" 
                   xmlns:s="library://ns.adobe.com/flex/spark" 
                   xmlns:mx="library://ns.adobe.com/flex/mx">
<fx:Declarations>
    <!-- Place non-visual elements (e.g., services, value objects) here -->
</fx:Declarations>

<fx:Script>
    <![CDATA[
        import mx.collections.ArrayCollection;

        private var _dataProviderList : ArrayCollection = new ArrayCollection(
            [
                "http://www.joomlaworks.net/images/demos/galleries/abstract/7.jpg",
                "http://www.joomlaworks.net/images/demos/galleries/abstract/8.jpg"
            ]
        );

    ]]>
</fx:Script>

<s:layout>
    <s:VerticalLayout/>
</s:layout> 

<s:List dataProvider="{_dataProviderList}">

</s:List>

<s:List itemRenderer="ImageItemRenderer" dataProvider="{_dataProviderList}">

</s:List>

</s:WindowedApplication>

Renderer

<?xml version="1.0" encoding="utf-8"?>
<s:ItemRenderer xmlns:fx="http://ns.adobe.com/mxml/2009" 
            xmlns:s="library://ns.adobe.com/flex/spark" 
            xmlns:mx="library://ns.adobe.com/flex/mx" 
            autoDrawBackground="true">


<mx:Image 
          source="{data}" 
          width="50" height="50"/>

</s:ItemRenderer>

If you realy want to use a laoder as object in your ArrayCollection, you could write your renderer as:

<?xml version="1.0" encoding="utf-8"?>
<s:ItemRenderer xmlns:fx="http://ns.adobe.com/mxml/2009" 
            xmlns:s="library://ns.adobe.com/flex/spark" 
            xmlns:mx="library://ns.adobe.com/flex/mx" 
            autoDrawBackground="true">

<fx:Script>
    <![CDATA[

        [Bindable]
        private var _loader : Loader;

        private function dataLoaded (evt : Event) : void
        {
            _loader = (data as Loader) 
        }

        override public function set data(value:Object):void
        {
            super.data = value;

            if (data is Loader) {
                // render items may be reuses (http://stackoverflow.com/questions/7328989/itemrenderer-switching-urlloader-images)
                (data as Loader).contentLoaderInfo.removeEventListener(Event.COMPLETE, dataLoaded);

                // data allready loaded
                if ((data as Loader).content) {
                    _loader = (data as Loader)
                }
                else {
                    // wait till data is loaded
                    (data as Loader).contentLoaderInfo.addEventListener(Event.COMPLETE,dataLoaded);
                }
            }
        }
    ]]>
</fx:Script>

<mx:Image 
    source="{_loader}" 
    width="50" height="50"/>



</s:ItemRenderer>