Traits for Audio elements?

Question

I am trying to create a very simple player example that responds to the type of media being loaded.
I can get it to display a play button for video, and not display it for a JPG. However, I can't seem to get it to work for audio; none of the traits you'd expect are being detected on the element when I specify an MP3 file (e.g. play trait, audio trait, time trait).
Below is my code for the player. I thought maybe the file wasn't loaded completely before I was trying to get its traits, so I tried an if statement -- but that's not the case for the other media types, and the if statement didn't seem to make a difference. Can you see a problem with my code below? Am I missing a step here?
TIA,
// Lisa
package
    import flash.display.Sprite;
    import org.osmf.containers.MediaContainer;
    import org.osmf.media.DefaultMediaFactory;
    import org.osmf.media.MediaElement;
    import org.osmf.media.MediaPlayer;
    import org.osmf.media.URLResource;
   import org.osmf.utils.URL;
    import org.osmf.traits.*;
    import flash.display.Graphics;
   import flash.display.Sprite;
   import flash.events.MouseEvent;
   import org.osmf.events.PlayEvent;
   import org.osmf.layout.LayoutUtils;
     * The metadata sets the SWF size to match that of the video.
    [SWF(width="640", height="480")]
    public class HelloPlayButton extends Sprite
        public function HelloPlayButton()
            // Create the container class that displays the media.
             var container:MediaContainer = new MediaContainer();
            addChild(container);
            // Create URL
            //var mediaURL:URL = new URL("../images/swing.jpg");
            var mediaURL:URL = new URL("../audio/train_1500.mp3");
            //var mediaURL:URL = new URL("../videos/S0004_VP6_1Mbps.flv");
            // Create the resource to play
            var resource:URLResource = new URLResource(mediaURL);
            // Create a mediafactory instance
            var mediaFactory:DefaultMediaFactory = new DefaultMediaFactory();
            // Create the MediaElement and add it to our container class.
            var myMediaElement:MediaElement =  mediaFactory.createMediaElement(resource);
            container.addMediaElement(myMediaElement);
            // Create a media player
            var mediaPlayer:MediaPlayer = new MediaPlayer();
            // Stop from autoplaying
            mediaPlayer.autoPlay = false;
            // Then assign the media
            mediaPlayer.media = myMediaElement;
            var playButton:Sprite = constructPlayButton();
            // Add event listeners
            playButton.addEventListener(MouseEvent.CLICK, function():void {
                               mediaPlayer.play();
            mediaPlayer.addEventListener(PlayEvent.PLAY_STATE_CHANGE, function():void {
               playButton.visible = !mediaPlayer.playing;
//tried this...
            if (myMediaElement.hasTrait(MediaTraitType.AUDIO)) {
                    var audio:AudioTrait = myMediaElement.getTrait(MediaTraitType.AUDIO) as AudioTrait;
                    trace("has audio trait");
// and also this...
            var loadable:LoadTrait = myMediaElement.getTrait(MediaTraitType.LOAD) as LoadTrait;
            var playable:PlayTrait = myMediaElement.getTrait(MediaTraitType.PLAY) as PlayTrait;
            if (loadable != null) {
                trace("This mediaElement is loadable!");
            if (playable !=null) {
                trace("This mediaElement is playable!");
                addChild(playButton);
            if (audio !=null) {
                trace("This mediaElement has an audio track!");
                addChild(playButton);
            function constructPlayButton():Sprite {
            var size = 100;
                var x = 330;
                var y = 225;
                var f = 1.2;
                var result:Sprite = new Sprite();
            var buttonArt:Graphics = result.graphics;
            buttonArt.lineStyle(1, 0, 0.5);
            buttonArt.beginFill(0xA0A0A0, 0.5);
            buttonArt.moveTo(x - size / f, y - size);
            buttonArt.lineTo(x + size / f, y);
            buttonArt.lineTo(x - size / f, y + size);
            buttonArt.lineTo(x - size / f, y - size);
            buttonArt.endFill();
            return result;

Answer 1

Current code, with comments...
package
    import flash.display.Sprite;
    import org.osmf.containers.MediaContainer;
    import org.osmf.media.DefaultMediaFactory;
    import org.osmf.media.MediaElement;
    import org.osmf.media.MediaPlayer;
    import org.osmf.media.URLResource;
    import org.osmf.utils.URL;
    import org.osmf.traits.*;
    import flash.display.Graphics;
    import flash.display.Sprite;
    import flash.events.MouseEvent;
    import org.osmf.containers.*;
    import org.osmf.elements.*;
    import org.osmf.events.*;
    import org.osmf.layout.*;
    import org.osmf.media.*;
    import org.osmf.metadata.*;
    import org.osmf.net.*;
    import org.osmf.net.dvr.*;
    import org.osmf.net.httpstreaming.*;
    import org.osmf.net.rtmpstreaming.*;
    import org.osmf.traits.*;
    import org.osmf.utils.*;
     * The metadata sets the SWF size to match that of the video.
    [SWF(width="640", height="480")]
    public class HelloPlayButton extends Sprite {
        public function HelloPlayButton() {
            // Create the container class that displays the media.
            var container:MediaContainer = new MediaContainer();
            addChild(container);
            // Create URL
            //var mediaURL:URL = new URL("../videos/S0004_VP6_1Mbps.flv");
            var mediaURL:URL = new URL("../images/swing.jpg");
            //var mediaURL:URL = new URL("../audio/train_1500.mp3");
//**THIS THROWS AN ERROR
            //var mediaURL:String = "../videos/S0004_VP6_1Mbps.flv";
            // Create the resource to play
            var resource:URLResource = new URLResource(mediaURL);
            // Create a mediafactory instance
            var mediaFactory:DefaultMediaFactory = new DefaultMediaFactory();
            // Create the MediaElement and add it to our container class.
            var myMediaElement:MediaElement =  mediaFactory.createMediaElement(resource);
            container.addMediaElement(myMediaElement);
            // Create a media player
            var mediaPlayer:MediaPlayer = new MediaPlayer();
            // Stop from autoplaying
            mediaPlayer.autoPlay = false;
            // Then assign the media
            mediaPlayer.media = myMediaElement;
            var playButton:Sprite = constructPlayButton();
            addChild(playButton);
            playButton.visible = false;
            // Add event listeners
         playButton.addEventListener(MouseEvent.CLICK, function():void {mediaPlayer.play();});
            mediaPlayer.addEventListener(PlayEvent.PLAY_STATE_CHANGE, function():void {playButton.visible = !mediaPlayer.playing; });
            mediaPlayer.addEventListener(MediaPlayerStateChangeEvent.MEDIA_PLAYER_STATE_CHANGE, mediaPlayerStateChanged);
            function mediaPlayerStateChanged(evt:MediaPlayerStateChangeEvent):void {
//***THIS DOESN'T FIRE FOR FLV, ONLY MP3 AND JPG
                    if (evt.state==MediaPlayerState.READY) {
                        trace("MediaPlayerState -- READY!");
                        registerTraits();
            function registerTraits() {
                trace("register traits");
                if (myMediaElement.hasTrait(MediaTraitType.LOAD)) {
                    var loadable:LoadTrait = myMediaElement.getTrait(MediaTraitType.LOAD) as LoadTrait;
                    trace("This mediaElement is loadable!");
                if (myMediaElement.hasTrait(MediaTraitType.PLAY)) {
                    var playable:PlayTrait = myMediaElement.getTrait(MediaTraitType.PLAY) as PlayTrait;
                    trace("This mediaElement is playable!");
                    addChild(playButton);
                    playButton.visible=true;
                if (myMediaElement.hasTrait(MediaTraitType.AUDIO)) {
                    var audio:AudioTrait = myMediaElement.getTrait(MediaTraitType.AUDIO) as AudioTrait;
                    trace("This mediaElement has an audio track!");
                    addChild(playButton);
                    playButton.visible=true;
//**IF I USE THIS SWITCH STATEMENT INSTEAD OF BASING ON TRAITS (ABOVE)
//**I GET A COMPILER ERROR
//**Error #1065: Variable org.osmf.elements::VideoElement is not defined.
                    /*switch (true) {
                        case myMediaElement is VideoElement :
                        trace("This is a VideoElement");
                        playButton.visible=true;
                    break;
                        case mediaPlayer.media is ImageElement :
                    break;
                        case mediaPlayer.media is AudioElement :
                        playButton.visible=true;
                    break;
                        case mediaPlayer.media is SWFElement :
                        playButton.visible=true;
                    break;
             function constructPlayButton():Sprite {
            var size = 100;
                var x = 330;
                var y = 225;
                var f = 1.2;
                var result:Sprite = new Sprite();
            var buttonArt:Graphics = result.graphics;
            buttonArt.lineStyle(1, 0, 0.5);
            buttonArt.beginFill(0xA0A0A0, 0.5);
            buttonArt.moveTo(x - size / f, y - size);
            buttonArt.lineTo(x + size / f, y);
            buttonArt.lineTo(x - size / f, y + size);
            buttonArt.lineTo(x - size / f, y - size);
            buttonArt.endFill();
            return result;