ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Display programming
container.removeChild(ball_C);
trace(container.getChildAt(0).name); // ball_A
trace(container.getChildAt(1).name); // ball_B
The removeChild() and removeChildAt() methods do not delete a display object instance entirely. They simply
remove it from the child list of the container. The instance can still be referenced by another variable. (Use the delete
operator to completely remove an object.)
Because a display object has only one parent container, you can add an instance of a display object to only one display
object container. For example, the following code shows that the display object tf1 can exist in only one container (in
this case, a Sprite, which extends the DisplayObjectContainer class):
tf1:TextField = new TextField();
tf2:TextField = new TextField();
tf1.name = "text 1";
tf2.name = "text 2";
container1:Sprite = new Sprite();
container2:Sprite = new Sprite();
container1.addChild(tf1);
container1.addChild(tf2);
container2.addChild(tf1);
trace(container1.numChildren); // 1
trace(container1.getChildAt(0).name); // text 2
trace(container2.numChildren); // 1
trace(container2.getChildAt(0).name); // text 1
If you add a display object that is contained in one display object container to another display object container, it is
removed from the first display object container’s child list.
In addition to the methods described above, the DisplayObjectContainer class defines several methods for working
with child display objects, including the following:
contains(): Determines whether a display object is a child of a DisplayObjectContainer.
getChildByName(): Retrieves a display object by name.
getChildIndex(): Returns the index position of a display object.
setChildIndex(): Changes the position of a child display object.
removeChildren(): Removes multiple child display objects.
swapChildren(): Swaps the front-to-back order of two display objects.
swapChildrenAt(): Swaps the front-to-back order of two display objects, specified by their index values.
For more information, see the relevant entries in the ActionScript 3.0 Reference for the Adobe Flash Platform.
Recall that a display object that is off the display list—one that is not included in a display object container that is a
child of the Stage—is known as an off-list display object.
Last updated 6/6/2012
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