Code behind for a flex application

Question

I'm working on Flex project and having problems with "connecting" the code-behind to the mxml file (It actually worked before in another project). Both files are in the default package.

Hydw.mxml:

<?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" xmlns="*">

    <s:TextArea id="txt_log" x="34" y="171" width="225" height="217"/>
</s:Application>

Hydw.as:

package  
{
    import flash.events.*;
    import flash.external.*;
    import flash.media.*;

    import mx.controls.TextArea;
    import mx.core.*;
    import mx.events.*;

    import spark.components.*;

    public class Hydw extends spark.components.Application
    {

        public var txt_log:spark.components.TextArea;

        public function Hydw ()
        {
            super();

            addEventListener(FlexEvent.CREATION_COMPLETE, this.creationCompleteHandler);
        }

        private function creationCompleteHandler(param1:FlexEvent) : void
        {
            WriteToLog("creationCompleteHandler");
        }

       public function WriteToLog(s:String) : void 
       {
           txt_log.text += s + "\n";
       }

I run the application (after releasing) and I see nothing in the TextArea. Why? By the way, I'm having trouble with the debugging for now, so I can't tell where's the failure exactly.

Answer 1

This is what you want

Hydw.mxml

<?xml version="1.0" encoding="utf-8"?>
<abstract:Hydw xmlns:fx="http://ns.adobe.com/mxml/2009" 
               xmlns:s="library://ns.adobe.com/flex/spark" 
               xmlns:mx="library://ns.adobe.com/flex/mx" 
               xmlns:abstract="test.pack.abstract.*" 
               minWidth="955" minHeight="600">
    <fx:Declarations>
        <!-- Place non-visual elements (e.g., services, value objects) here -->
    </fx:Declarations>
    <s:TextArea id="txt_log" x="34" y="171" width="225" height="217"/>
</abstract:Hydw>

and your Hydw.as:

package test.pack.abstract
{
    import mx.events.FlexEvent;

    import spark.components.Application;
    import spark.components.TextArea;

    [Bindable]
    public class Hydw extends Application
    {

        public var txt_log:TextArea;

        public function Hydw()
        {
            super();
            addEventListener(FlexEvent.CREATION_COMPLETE, init);
        }

        public function init(evt:FlexEvent):void
        {


        }

    }
}

any visual component used in .mxml code you want to use in .as class must be declared as public binded variable in your .as class or simply declare your .as class as [Bindable]

That's All

Answer 2

Obviously it didn't work. There need to make some changes in ActionScript and mxml file.

First: Remove package and class from ActionScript file like:

import mx.events.FlexEvent;

public function creationCompleteHandler(param1:FlexEvent) : void
{
    WriteToLog("creationCompleteHandler");
}

public function WriteToLog(s:String) : void 
{
    txt_log.text += s + "\n";
}

Because It is in default package there isn't required to defined package and class.

Second:

Remove public var txt_log:spark.components.TextArea; from as file. Because it will conflict txt_log with id of textArea in mxml file.

Third:

Remove addEventListener(FlexEvent.CREATION_COMPLETE, this.creationCompleteHandler); from as file and give creation complete event in mxml file. like:

<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:Declarations>
        <!-- Place non-visual elements (e.g., services, value objects) here -->
    </fx:Declarations>

    <fx:Script source="Hydw.as" />

        <s:TextArea id="txt_log" x="34" y="171" width="225" height="217"/>
</s:Application>

And another thing is you forget to include as file inside mxml. like:

<fx:Script source="Hydw.as" />

Hope you understand and help to move forward.