Question

I have one MXML File as

<objecthandles:ObjectHandles xmlns:fx="http://ns.adobe.com/mxml/2009"                            xmlns:s="library://ns.adobe.com/flex/spark"  backgroundAlpha="1"                            xmlns:mx="library://ns.adobe.com/flex/mx"
allowRotate="true" minHeight="25" minWidth="60" height="100" width="200">

<s:BorderContainer  id="borderCon" width="100%" height="100%" minHeight="25" minWidth="60" 
                        backgroundAlpha="0" borderVisible="false" borderAlpha="0">
         <s:HGroup id="hgText" width="100%" height="100%" gap="0" >
            <mx:TextArea id="txtAdd" width="100%" height="100%" color="black" 
                         minHeight="25" minWidth="60" horizontalScrollPolicy="off" verticalScrollPolicy="off" focusOut="txtAddKeyUpHandler(event)"  
                         keyUp="txtAddMirrorKeyUpHandler(event)"
                         creationComplete="onTextCreationComplete()" />
        </s:HGroup>
</s:BorderContainer>

</objecthandles:ObjectHandles>

When ever i create the object of the Fileas

var txtElement:TextElement = new TextElement();
txtElement.txtAdd.text = “Hello”;

Then it showing the null object reference that
txtElement.txtAdd seems to be null

Need Perfect Solution?

Answer 1

In the Flex component lifecycle subcomponents will not be created until the parent component is added to the displaylist. Only when the component is added to the displaylist and fully built, will you be able to access its subcomponents. When the component is completely ready for usage, it will dispatch a FlexEvent.CREATION_COMPLETE event.

So do something like this:

var txtElement:TextElement = new TextElement();
txtElement.addEventListener(FlexEvent.CREATION_COMPLETE, initTxtElement);
addElement(txtElement);

private function initTxtElement(event:FlexEvent):void {
    txtElement.txtAdd.text = "Hello";
}

Or better yet, since it’s a custom component: expose the ‘text’ property as a property of ‘TextElement’ and handle the deferred setting of the property internally, so that you can write: txtElement.text = "hello".