ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Display programming
Traversing the display list
Flash Player 9 and later, Adobe AIR 1.0 and later
As you’ve seen, the display list is a tree structure. At the top of the tree is the Stage, which can contain multiple display
objects. Those display objects that are themselves display object containers can contain other display objects, or display
object containers.
Display Object
Display Object
Stage
Instance of
the main class of
the SWF file
Display Object
Container
Display Object
Container
Display Object
Container
Display Object
Container
Display Object
The DisplayObjectContainer class includes properties and methods for traversing the display list, by means of the child
lists of display object containers. For example, consider the following code, which adds two display objects, title and
pict, to the container object (which is a Sprite, and the Sprite class extends the DisplayObjectContainer class):
var container:Sprite = new Sprite();
var title:TextField = new TextField();
title.text = "Hello";
var pict:Loader = new Loader();
var url:URLRequest = new URLRequest("banana.jpg");
pict.load(url);
pict.name = "banana loader";
container.addChild(title);
container.addChild(pict);
The getChildAt() method returns the child of the display list at a specific index position:
trace(container.getChildAt(0) is TextField); // true
You can also access child objects by name. Each display object has a name property, and if you don’t assign it, Flash
Player or AIR assigns a default value, such as "instance1". For example, the following code shows how to use the
getChildByName() method to access a child display object with the name "banana loader":
Last updated 6/6/2012
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