ActionScript 3.0 事件机制小结

这次先把ActionScript 3.0 事件机制总结一下先吧，这里只说一下自定义类发送事件的3中方式，因为在设计模式中是比较常用的。例如MVC。

关于自定义事件，主要由于两个类：事件类（Event）,事件发送类（EventDispatcher）。我们讨论的自定义发送事件，就是如何使对象能够发送事件。

方式一：继承EventDispatcher类

package
{
    import flash.display.Sprite;
    import flash.events.Event;
    import flash.events.EventDispatcher;
     
    /**
     * ...
     * @author 橡树小屋
     */
    public class estends extends Sprite
    {
        function estends() {
            //第一种
            var dispatcher:extendsDispatcher = new extendsDispatcher();
            dispatcher.addEventListener(extendsDispatcher.ACTION, actionH);
            dispatcher.doSome();
            //第二种
            var dispatcher1:EventDispatcher = new EventDispatcher();
            dispatcher1.addEventListener("secDispatcher", actionH);
            dispatcher1.dispatchEvent(new Event("secDispatcher"));
            //或者
            dispatcher.addEventListener("thurdDispatcher", actionH);
            dispatcher.dispatchEvent(new Event("thurdDispatcher"));
        }
        private function actionH(e:Event):void {
            trace(e);
        }
    }
     
}
import flash.events.Event;
import flash.events.EventDispatcher;
 
class extendsDispatcher extends EventDispatcher {
    public static var ACTION:String = "action";
    public function doSome():void {
        dispatchEvent(new Event(extendsDispatcher.ACTION));
    }
}

只要继承EventDispatcher类，就可以直接用EventDispatcher类的方法发送事件，方便简单。

方式二：复合EventDispatcher对象

package
{
     
    /**
     * ...
     * @author 橡树小屋
     */
    import flash.display.Sprite;
    import flash.events.Event;
     
    public class compont extends Sprite
    {
        public function compont() {
            var dis:compont1 = new compont1();
            dis.getEventDispatch().addEventListener(compont1.ACTION, show);
            dis.doSome();
        }
        private function show(e:Event):void {
            trace(e);
        }
    }
     
}
import flash.events.Event;
import flash.events.EventDispatcher;
 
class compont1 {
    private var _dispatcher:EventDispatcher;
    public static var ACTION:String = "action";
    public function compont1() {
        _dispatcher = new EventDispatcher();
    }
    public function getEventDispatch():EventDispatcher {
        return _dispatcher;
    }
    public function doSome():void {
        _dispatcher.dispatchEvent(new Event(compont1.ACTION));
    }
}

所谓的复合，其实就是用EventDispatcher发送事件而已，因为EventDispatcher本身就是个事件发送类，一般情况下，用EventDispatcher发送事件反而会更简单。

方式三：实现IEventDispatcher接口

package
{
    import flash.display.Sprite;
    import flash.events.Event;
     
    /**
     * ...
     * @author 橡树小屋
     */
    public class implement extends Sprite
    {
         
        public function implement() {
            var impObj:implete = new implete();
            impObj.addEventListener(implete.ACTION, actionH);
            impObj.dispatchEvent(new Event(implete.ACTION));
        }
        private function actionH(e:Event):void {
            trace(e);
        }
    }
     
}
import flash.events.Event;
import flash.events.EventDispatcher;
import flash.events.IEventDispatcher;
 
class implete implements IEventDispatcher {
    public var _dispatcher:EventDispatcher;
    public static const ACTION:String = "action";
     
    public function implete() {
        _dispatcher = new EventDispatcher();
    }
    //实现5个方法
    public function addEventListener(type:String,listener:Function,useCapture:Boolean=false,priority:int=0,useWeakReference:Boolean=true):void {
        _dispatcher.addEventListener(type, listener, useCapture, priority, useWeakReference);
         
    }
    public function dispatchEvent(evt:Event):Boolean {
        return _dispatcher.dispatchEvent(evt);
    }
    public function hasEventListener(type:String):Boolean {
        return _dispatcher.hasEventListener(type);
    }
    public function removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void {
        _dispatcher.removeEventListener(type,listener,useCapture);
    }
    public function willTrigger(type:String):Boolean {
        return _dispatcher.willTrigger(type);
    }
}