arcgis js api 点击面 ，实现面颜色渐变效果

 var interval_index;
 function showFeature(feature) {
 
 //STYLE_FORWARD_DIAGONAL
 var symbol = new esri.symbol.SimpleFillSymbol(
 esri.symbol.SimpleFillSymbol.STYLE_SOLID,
 new esri.symbol.SimpleLineSymbol(
 esri.symbol.SimpleLineSymbol.STYLE_SOLID,
 new dojo.Color([ 255, 0, 0 ]), 4), new dojo.Color([255,255,0,0.5]));
 feature.setSymbol(symbol);
 var dbx_json = feature.geometry.toJson();
 var polygonJson  = {"rings":dbx_json.rings,"spatialReference":dbx_json.spatialReference};
 var polygon = new esri.geometry.Polygon(polygonJson);
 
 var graphic = new esri.Graphic(polygon,symbol,feature.attributes,feature.infoTemplate);
 map.graphics.add(graphic);
 var i = 0;
 interval_index = setInterval(function(){
     var color_sz = [255,255,0,0.5]; 
     if(i%2==0){
       color_sz = [22,26,228,0.5];
     }
     i++;
     var graphic = map.graphics.graphics[0];
     console.info(interval_index);
     graphic.symbol.setColor(new dojo.Color(color_sz));
     map.graphics.redraw(); // 重新绘制图形
     if(i==20){
       i=0;
     }
}, 500);

}

 其中关键就是 map.graphics.redraw();  然后每隔多长时间重新 redraw 就可以了！ 

效果如下图所示：