Open a new document in Flash Pro. Save this document as MediaComponent_mp3.fla.

Rename Layer 1 to clbSounds. On frame 1 of this layer, drag an instance of the List component from the UI Components folder of the Components panel to the Stage. Place the instance near the top-left corner of the Stage. In the Properties panel, name this instance clbSounds.

Create a new layer, and name it cmpPlayer. On frame 1 of this layer, drag an instance of the MediaPlayback component to the Stage, to the right of the clbSounds instance. In the Properties panel, name this instance cmpPlayer and set its height to 80. Click the Launch Component Inspector button, and in the Parameters tab of the Component Inspector panel, select the MP3 option and the On value for the Control Visibility setting, as shown in Figure 7-31.

Figure 7-31. The settings for the MediaPlayer instance in the Component Inspector panel

Now you're ready to add the ActionScript code to populate the list and trigger the MediaPlayback component when an item in the list is selected. Create a new layer named Actions, and drag this layer to the top of the layer stack. Select frame 1 of this layer, and open the Actions panel (F9). Add the following code:

import mx.controls.List;
import mx.controls.MediaPlayback;

var clbSounds:mx.controls.List;
var cmpPlayer:mx.controls.MediaPlayback;

var dp:Array = [ {label: "Dog", data: "dog.mp3"},
                 {label: "Cat", data: "cat.mp3"},
                 {label: "Duck", data: "duck.mp3"},
                 {label: "Bird", data: "bird.mp3"}];

clbSounds.dataProvider = dp;

var oSounds:Object = new Object( );
oSounds.change = function (oEvent:Object) {
  var sVal:String = oEvent.target.selectedItem.data;
  cmpPlayer.contentPath = "rtmp://209.29.151.23/ch07/" + sVal;
  cmpPlayer.play( );
};
clbSounds.addEventListener("change", oSounds);

This block of code creates a data provider for the clbSounds instance. The dp array contains four objects, each with a label and data property. The oSounds object is a listener whose change( ) method is invoked whenever an item in the list is clicked. For this example, the contentPath of the cmpPlayer instance uses the public URL on the book's server, but you can change this path to reflect the location of your own broadcast application.

Save the document, and test the movie (Ctrl-Enter or Cmd-Enter). When you click the Dog item in the list, you will hear the sound of a dog barking. The dog.mp3 file is streaming from the FlashCom Server. If you select another item in the list, you will hear that sound play.