ActionScript 3.0 Programming: Overview, Getting Started, and Examples of New Concepts

Packages and Classes

Probably the most important feature to grasp about ActionScript 3.0 is how to work with packages and classes. In fact, your entire workflow initially rests on your ability to recognize that you only deal with certain features of ActionScript at any one time. For example, if you want to work with a text field, you have to first import the TextField class from the flash.text package. Of course, you'll need to know that the TextField class is in the flash.text package, as well as where other classes are stored. To get started, take a look at the script in Example 1:

Example 1. (download this code sample at http://examples.oreilly.com/actionscript3qr)

package
{
    import flash.display.Sprite;
    import flash.text.TextField;
    public class ShowText extends Sprite
    {
        public function ShowText():void
        {
            var actionText:TextField=new TextField();
            var msg:String="Hello ActionScript 3.ohhhhh";
            actionText.text=msg;
            this.addChild(actionText);
            actionText.width=((msg.length)*12)+4;
            actionText.height=16;
            actionText.x=200;
            actionText.y=150;
        }
    }
}

Save the script as ShowText.as. To test this script, use the following steps:

1. Open a new Flash document, and in the Document class window in the Properties panel, type in the class name, ShowText, as shown in Figure 1.

   

   Figure 1. The script is associated with the Flash document through the Document class

2. Save the Flash document as TextSimple.fla in the ...