CODEWITHSUNDEEP
apache-flexfunctionactionscriptattributes
randomUser56789
randomUser56789

Reputation: 936

Writing function inside attribute in flex

Can I write a function inside an attribute in flex? Something like this:

<s:Button id="btn" label="text" visible="{foo()}"/>
private function foo():Boolean
{
  //do something
}

It seems it doesn't work at least for me.
I know that I can write like visible="{something == true &amp;&amp; somethingElse == false}" etc. But I need it to do more like for loops etc.

Upvotes: 0

Views: 685

Answers (2)

Alexandru
Alexandru

Reputation: 336

Try this:

[Bindable(event="update")]
private function foo():Boolean
{
   return a && b && c;
}

and when a or b or c is change just do this:

dispatchEven(new Event("update"));

Upvotes: 1

Jason Sturges
Jason Sturges

Reputation: 15955

This implementation is not bindable - if the result of foo() changes, it will not be reflected on your display list.

Although, I think this should work once upon creation complete:

<?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:Script>
        <![CDATA[
            private function foo():Boolean
            {
                return false;
            }
        ]]>
    </fx:Script>

    <s:Button label="text"
              visible="{foo()}" />

</s:Application>

A better approach would be to incorporate a presentation model, leveraging binding as seen here:

<?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"
               creationComplete="creationCompleteHandler(event)">

    <fx:Script>
        <![CDATA[
            import mx.events.FlexEvent;

            [Bindable]
            public var presentationVisible:Boolean = true;

            private var timer:Timer = new Timer(500);

            private function foo():void
            {
                presentationVisible = Math.random() > 0.5 ? true : false;
            }

            protected function creationCompleteHandler(event:FlexEvent):void
            {
                timer.addEventListener(TimerEvent.TIMER, timerHandler);
                timer.start();
            }

            protected function timerHandler(event:TimerEvent):void
            {
                foo();
            }
        ]]>
    </fx:Script>

    <s:Button label="text"
              visible="{presentationVisible}" />

</s:Application>

Upvotes: 0

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