Flex3中的Interactivity

Sky-Tiger

when
the Event.ADDED event occurs, the added child, its new parent container, and all
ancestors of that container are notified that the child was added. Likewise, when the
Event.REMOVED event occurs, the removed child and its old parent container and all
ancestors of that container are notified that the child is about to be removed

Sky-Tiger

Therefore
the Event.ADDED and Event.REMOVED events can be used in two different ways:
• A DisplayObjectContainer instance can use the Event.ADDED and Event.REMOVED
events to detect when it has gained or lost a display descendant.
• A DisplayObject instance can use the Event.ADDED and Event.REMOVED events to
detect when it has been added to or removed from a parent container.