[转] 事件发送之复合EventDispatcher对象

mac2022-06-30  79

EventDispatcher类详解 Evevt和EventDispatcher类在as3的事件机制中是很重要的角色,dispatchEvent()是EventDispatcher类的一个事件发送方法,它可以发送出Event类或其子类的实例,在as3中所有的显示对象都可以发送事件,因为as3中所有的显示对象都是EventDispatcher子类DisplayObject的实例。        发送事件有三种方式:继承EventDispatcher,如sprite等显示对象、复合EventDispatcher或其子类、实现IEventDispatcher接口。        个人认为复合EventDispatcher在实际应用中用的比较多,没有找到合适例子,自己写了一个很简单的,仅供参考,为了演示把简单的问题复杂话了,首先画一个矩形,点击矩形后发送一个事件,矩形接收事件后alpha变为0; 自定义事件: package{        import flash.events.Event;        public class MyEvent extends Event{              public static const ALPHA:String = "alpha";                public function MyEvent(type:String, bubbles:Boolean=false, cancelable:Boolean=false){                 super(type, bubbles, cancelable);                }          } } package{ import flash.display.Sprite; public class Sample extends Sprite{         public function Sample(){              this.graphics.beginFill(0xff6600);              this.graphics.drawRect(50,50,100,50);              this.graphics.endFill();              this.addEventListener(MyEvent.ALPHAALPHA,blackHandler);        }        private function blackHandler(evt:MyEvent){              this.alpha = 0;        }     } } 主类: package{        import flash.display.Sprite;        import flash.events.MouseEvent;        public class Main extends Sprite{               private var sample:Sample;               public function Main(){                sample = new Sample();                //注册事件侦听器                sample.addEventListener(MouseEvent.CLICK,clickHandler);                addChild(sample);         }         private function clickHandler(evt:MouseEvent){               //发送事件                sample.dispatchEvent(new MyEvent(MyEvent.ALPHA));         }      } } 注:在as3中只有事件的发送者才能侦听事件。在Main类中sample实例发送的事件也只有sample注册的侦听器才能侦听,在Sample中的this正是指向了sample。 事实上,没有什么要比发现、培养、呵护、调整自己的心智的力量更重要的事情了........

转载于:https://www.cnblogs.com/pelephone/articles/event-EventDispatcher-as3.html

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