creationComplete getting called doesn't mean that the dataProvider was
also getting set.
showData was getting called between creation complete and the
assignment to dataProvider.
I made few changes to your code, hopefully it will resolve the issue.
package components
{
import flash.events.Event;
import mx.containers.Canvas;
import mx.controls.TextArea;
public class BindableListTextAS extends Canvas
{
[Bindable]
private var _dataProvider:Array;
private var tf:TextArea;
public function BindableListTextAS()
{
tf = new TextArea();
addChild(tf)
// addEventListener("creationComplete", showData);
}
public function set dataProvider (_dp :Array) :void {
_dataProvider = _dp;
showData();
}
private function showData():void
{
var dpLen:int = _dataProvider.length;
tf.text = "";
for(var i:int = 0; i<dpLen; i++)
{
tf.text += _dataProvider[i].label;
}
}
}
}
Thanks,
Gaurav
--- In [email protected], "Merrill, Jason"
<[EMAIL PROTECTED]> wrote:
>
> My head is swimming reading the archives and Flex help docs about
> binding data to a custom component. In the simplest form, it's easy
> enough for me to do data binding: i.e. set a repeater's dataProvider to
> a [Bindable] property. That works. The repeater which repeats a series
> of Flex checkboxes and auto-updates the number of checkboxes when the
> data changes. Great.
>
> The part I'm struggling with is binding data to custom components. My
> question is really 2-in-1:
>
> 1) How to get the custom AS3-written component I wrote to respond to
> changes in the data
> 2) How to get the inital data into the component without getting the
> error: "Cannot access a property or method of a null object reference."
> which seems to occur because the method which uses the data is being
> called before the data is set. As you will see in the code below, I
> tried setting the data after the creationComplete event is heard, but
> that was not enough:
>
> Surely this has been done a gazillion times before. Below is my lame
> attempt to do #2, and only half-way to do #1 since I'm not sure what to
> do. My MXML file is shown first, and then the custom AS3 component (both
> are written strictly for simplicity):
>
> <?xml version="1.0" encoding="utf-8"?>
> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml";
> layout="absolute" xmlns:c="components.*" creationComplete="init()">
> <mx:Script>
> <![CDATA[
> [Bindable]
> private var dataArr:Array;
>
> private function init():void
> {
> dataArr = new Array( {label:"Here"},
> {label:"is"},
> {label:"some"},
> {label:"data."})
> }
>
> private function changeArray():void
> {
> dataArr = [ {label:"Now"},
> {label:"there"},
> {label:"is"},
> {label:"a"},
> {label:"new"},
> {label:"set"},
> {label:"of"},
> {label:"data."}];
>
> }
> ]]>
> </mx:Script>
> <mx:Button label="change" click="changeArray()"/>
> <c:BindableListTextAS dataProvider="{dataArr}" x="590" y="100"
> backgroundColor="0x666666" width="500" height="400"/>
> </mx:Application>
>
> /********************************
> The BindableListTextAS component:
> */
>
> package components
> {
> import flash.events.Event;
> import mx.containers.Canvas;
> import mx.controls.TextArea;
>
>
> public class BindableListTextAS extends Canvas
> {
> [Bindable]
> public var dataProvider:Array;
>
> private var tf:TextArea;
>
> public function BindableListTextAS()
> {
> tf = new TextArea();
> addChild(tf)
> addEventListener("creationComplete", showData);
> }
>
> private function showData(e:Event):void
> {
> var dpLen:int = dataProvider.length;
> for(var i:int = 0; i<dpLen; i++)
> {
> tf.text += dataProvider[i].label;
> }
> }
>
> }
> }
>
>
> Jason Merrill
> Bank of America
> GT&O L&LD Solutions Design & Development
> eTools & Multimedia
>
> Bank of America Flash Platform Developer Community
>
