arcgis for js symbol图标的变化

需求是图标有hover效果 ，如下

思路 ：

1、创建图片标记，并赋值；

　　 args.rendererArgs = new RenderArgs();

    args.rendererArgs.type = RenderType.CLASSBREAKS;

    args.rendererArgs.attributeField = "value";

var symbolNormal = new PictureMarkSymbolArgs();
    symbolNormal.url = getMapImageIcon(remoteMeterName,"0");
    symbolNormal.height = 40;
    symbolNormal.width = 40;
    symbolNormal.xoffset = 0;
    symbolNormal.yoffset = 0;
    args.rendererArgs.symbols.push(symbolNormal);

var symbolNormalFocus = new PictureMarkSymbolArgs();
    symbolNormalFocus.url = getMapImageIcon(remoteMeterName,"1");
    symbolNormalFocus.height = 40;
    symbolNormalFocus.width = 40;
    symbolNormalFocus.xoffset = 0;
    symbolNormalFocus.yoffset = 0;
    args.rendererArgs.symbols.push(symbolNormalFocus);

var symbolNormalLight = new PictureMarkSymbolArgs();
    symbolNormalLight.url = getMapImageIcon(remoteMeterName, "2"); //正常高亮图标
    symbolNormalLight.height = 40;
    symbolNormalLight.width = 40;
    args.rendererArgs.symbols.push(symbolNormalLight); 

var symbolAlarmLight = new PictureMarkSymbolArgs();
    symbolAlarmLight.url = getMapImageIcon(remoteMeterName, "3"); //报警高亮图标
    symbolAlarmLight.height = 40;
    symbolAlarmLight.width = 40;
    args.rendererArgs.symbols.push(symbolAlarmLight);

    args.rendererArgs.values.push(0);
    args.rendererArgs.values.push(0.9);
    args.rendererArgs.values.push(1.9);
    args.rendererArgs.values.push(2.9);
    args.rendererArgs.values.push(3.9);

2、在创建图层的时候写入mouse-over事件，并修改移入时的velue值；并刷新图层；完成。

layer.on("mouse-over", lang.hitch(this, function (evt) {

　　dijitPopup.close(dialog);

　　var g = evt.graphic;

if(g.attributes.value=="0"){
   g.attributes.value = "2";
   layer.refresh();
}else if(g.attributes.value=="1"){
   g.attributes.value = "3";
   layer.refresh();
}
}））