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Question

I am a bit stumped. I thought it was possible to call a function within the fx:Script tag simply by referencing the function ("display_album()" as in the code below). It would make sense to have that function call outside the curly braces, but when I do, the debugger in FlashBuilder gives me the 1180 error, call to a possibly undefined method.

I can call the function with a button click (which makes sense too), and I get the proper trace in the FlashBuilder debugger.

But I am curious as to how I can call a function in the tag without adding a button. Thanks!

 <?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" 
               xmlns:s="library://ns.adobe.com/flex/spark" 
               xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600">
    <fx:Declarations>
        <!-- Place non-visual elements (e.g., services, value objects) here -->
    </fx:Declarations>

    <fx:Script>
        <![CDATA[

            public function display_album():void
            {
                var album:String = "The White Album";
                trace (album);

            }

            display_album();

        ]]>
    </fx:Script>
    <s:Button x="192" y="259" label="Button" click = "display_album()"/>

</s:Application>

Answer 1

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" 
           xmlns:s="library://ns.adobe.com/flex/spark" 
           xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600"
           initialize="init()">
<fx:Declarations>
    <!-- Place non-visual elements (e.g., services, value objects) here -->
</fx:Declarations>

<fx:Script>
    <![CDATA[
        private function init():void
        {
          display_album();
        }

        public function display_album():void
        {
            var album:String = "The White Album";
            trace (album);

        }

    ]]>
</fx:Script>
<s:Button x="192" y="259" label="Button" click = "display_album()"/>

I hope this helps.

Answer 2

You can't call an instance function like that, because it runs before the constructor is called. Since the instance itself has not been initialized yet, there is no scope within with this function can be executed. You can only call class functions before the constructor is called.

You can either convert the method into a class method through the static keyword (probably not right in this case), or trigger this method on the creationComplete event.