自定义事件类

package lu.leon.events {
	import flash.events.Event;

	/**
	 * ...
	 * @author LeonLu
	 */
	public class PicChosenEvent extends Event {
		public static const CHOSEN:String = "chosen";
		public var id:int;

		public function PicChosenEvent(type:String, id_:int, bubbles:Boolean = false, cancelable:Boolean = false){
			this.id = id_;
			super(type, bubbles, cancelable);
		}
	}
}

该自定义事件中，定义了2个属性：CHOSEN、id，其中，CHOSEN是以后在实例化PicChosenEvent时需要侦听的事件类型（也可以理解为需要PicChosenEvent干的事情类型），id则是自定义事件的目的所在，侦听当发生自定义的事件类型CHOSEN时，返回id，即：e.id，此处的e是PicchosenEvent的实例。

pic.addEventListener(MouseEvent.CLICK, picClick, false, 0, true);
function picClick(e:MouseEvent):void {
	var currentSmallPic:MobileSmallPicItem = e.currentTarget as MobileSmallPicItem;
	if (currentSmallPic != oldSmallPic) {
		if (oldSmallPic) {
			oldSmallPic.gotoAndStop(1);
		}
		currentSmallPic.gotoAndStop(2);
		oldSmallPic = currentSmallPic;

		//为PicChosenEvent构造函数传入2个参数：事件类型PicChosenEvent.CHOSEN和oldSmallPic.id，
		//其中PicChosenEvent.CHOSEN不能省略PicChosenEvent，否则就是指当前类的CHOSEN属性了
		dispatchEvent(new PicChosenEvent(PicChosenEvent.CHOSEN, oldSmallPic.id));
	}
}

smallPicsBrowser.addEventListener(PicChosenEvent.CHOSEN, smallPicChosen, false, 0, true);
function smallPicChosen(e:PicChosenEvent):void{
	trace(e.id);
}