ActionScript 3 AS3：单例事件控制器

Posted 2021-05-23

-EventCentral.as-
package {

import flash.events.*;

    public class EventCentral extends EventDispatcher {
    private static var instance:EventCentral;
    public static function getInstance():EventCentral {
      if (instance == null){
         instance = new EventCentral(new SingletonBlocker());
      }
      return instance;
}
      public function EventCentral(blocker:SingletonBlocker):void{
        super();
        if (blocker == null) {
           throw new Error("Error: instantiation failed; Use EventCentral.getInstance()");
       }
}
        public override function dispatchEvent($event:Event):Boolean{
        return super.dispatchEvent($event);
}
}
}
internal class SingletonBlocker {}

--ProjectEvent.as--

package {
      import flash.events.Event
      public class ProjectEvent extends Event {
        public static const SOME_EVENT:String = "ProjectEvent.onSomeEvent";
        public var params:Object;
        public function ProjectEvent($type:String,$params:Object = null){
          super($type,true,true);
          this.params = $params;
}
       public override function clone():Event {
           return new ProjectEvent(this.type,this.params);
}
     override public function toString():String{
          return ("[Event ProjectEvent]");
}
}
}

To set up a listener:

EventCentral.getInstance().addEventListener('ProjectEvent.SOME_EVENT',handleSomeEvent);
function handleSomeEvent(event:ProjectEvent):void{
trace(event.params.param1);
}

to dispatch:

EventCentral.getInstance().dispatchEvent(new ProjectEvent('ProjectEvent.SOME_EVENT',{param1:'something'}));