Flex / Action脚本编程 - 未正确删除侦听器？

Question

我在flex编程方面是全新的，在我的代码中，我觉得听众没有被正确删除。下面是代码作为我所做的一个例子。这个代码第一次被执行，一切都很好，我看到了各种警报，我已经添加了跟踪路径。但是从第二次开始只看到警报信息：

 Alert.show('saveMapImageAndForward:before 2');

没有其他消息。我究竟做错了什么？我是否正确地正确移除了听众？代码路径应该是： saveMapImageAndForward-＆GT; processMapImage-＆GT; addMapImage - ＆gt; saveMapImage

我创建了一个全局计时器：     private var timer：Timer = new Timer（1000）;

这是我的代码：

public function saveMapImageAndForward(projectLocationWKT:String, projectMapType:String, hasMapImageFromIPaCMap:String, projectName:String):void {
    this.projectLocationWKT = projectLocationWKT;
    this.projectMapType = projectMapType;
    this.hasMapImageFromIPaCMap = hasMapImageFromIPaCMap;
    this.projectName = projectName;
    Alert.show('saveMapImageAndForward:before 2');
    _map.addEventListener(ZoomEvent.ZOOM_END, processMapImage);
    GlobalDispatcher.dispatchEvent(new AppEvent(DrawManager.ZOOM_TO_SELECTION));

}


//On zoom_end this function will be called
private function processMapImage(pEvent:ZoomEvent):void {
    Alert.show('inside processMapImage');
    _map.removeEventListener(ZoomEvent.ZOOM_END, processMapImage);
     Alert.show('after ZoomEvent removed');
    timer.addEventListener(TimerEvent.TIMER,addMapImage);
    timer.start();

}

//I need a delay of 1 sec so starting a timer
 private function addMapImage(pEvent:TimerEvent):void {
    Alert.show('inside addMapImage');
    timer.stop();
    timer.removeEventListener(TimerEvent.TIMER,addMapImage);
    Alert.show('after timer removed');
    saveMapImage();

}

//after 1 sec this method will be called
public function saveMapImage():void {

  //do something
}

有人可以帮忙吗？