flex image mouseover有关问题 _Web开发

flex image mouseover问题
用的是arcgisserver for flex 做电子地图开发
遇到一个问题，请教各位大虾：
先从后台数据库查询，得到n个几何对象，包括点，线等
再这把查询到得对象，变为graphic ，添加到一个layer里面，通过map.addLayer(layer);在地图上显示
graphic如果是POINT的话，它的SYMBOL是一个PictureMarkerSymbol，代码如下：

Java code

var graphic:Graphic = new Graphic(result.feature.geometry); 
                   if(result.feature.geometry.type.toString() == "esriGeometryPoint"){
                    graphic.symbol = eps.getPicUrl( result.layerName,
                                                       result.feature.attributes["分类"],
                                                       "0",
                                                       result.feature.attributes["ANGLE"]);
                }else{
                    graphic.symbol = symbolM.getFeatureSymbol(graphic.geometry.type.toString());
                }
                   var obj:Object = {
                                       layername:result.layerName, 
                                       subtype:result.feature.attributes["分类"],
                                       angle:result.feature.attributes["ANGLE"],
                                         objectid:result.feature.attributes.OBJECTID,
                                         type:result.feature.geometry.type.toString()
                                     };
                   graphic.attributes = obj;
                   graphic.toolTip = result.feature.attributes["设备编码"];
                  graphic.addEventListener(MouseEvent.MOUSE_OVER, mouseOver);
                graphic.addEventListener(MouseEvent.MOUSE_OUT, mouseOut);
                   graphic.addEventListener(MouseEvent.CLICK, function(evt:MouseEvent):void{
                    var g:Graphic = evt.currentTarget as Graphic;
                    queryUtils.getAttributeByID(g.attributes.layername, 
                                    g.attributes.objectid, hbBaseMapLayer, onRusult );
                });
                   featureServerLayer.add(graphic);
                   
                   function mouseOver(evt:MouseEvent):void{
                    var g:Graphic = evt.currentTarget as Graphic;
                        if(g.geometry.type.toString() == "esriGeometryPoint"){    
                            var object:Object = g.attributes;
                            g.symbol = eps.getPicUrl(object.layername,
                                                        object.subtype,
                                                        "1",
                                                        object.angle);
                        }else{
                            g.symbol = symbolM.getSelectSymbol(g.attributes.type);
                        }
                }
                
                function mouseOut(evt:MouseEvent):void{
                    var g:Graphic = evt.currentTarget as Graphic;
                        if(g.geometry.type.toString() == "esriGeometryPoint"){
                            var object:Object = g.attributes;
                            g.symbol = eps.getPicUrl(object.layername,
                                                        object.subtype,
                                                        "0", 
                                                        object.angle);
                        }else{
                            g.symbol = symbolM.getFeatureSymbol(g.attributes.type);
                        }
                }

问题是：当鼠标移动到graphic（POINT）的symbol上，图片总是一直在切换，不是只切换一次

------解决方案--------------------
随便看了下，貌似没看出问题来，我一直都是这样写的。