Arcgis api for javascript 图层的获取与更替

方法一：

在function init()中：

…… 

   var landusePointLayer = new esri.layers.FeatureLayer("http://10.0.0.28/arcgis/rest/services/editFeature/FeatureServer/0", {
        mode: esri.layers.FeatureLayer.MODE_ONDEMAND,
        outFields: ["*"],
        id: "HotspotLayer"
    });
    map.addLayers([landusePointLayer]);

……
//直接获取指明的layer
var featureHotspotLayer = map.getLayer("HotspotLayer");
var featurelayers=map.getLayer(map.layerIds[2]);
map.removeLayer(map.getLayer(map.layerIds[0]));

//例子，更替底图层
function mapBaseEsri(){ 
    dojo.addOnLoad(function(){
    map.removeLayer(map.getLayer(map.layerIds[2]));
    tiledMapServiceLayer = new esri.layers.ArcGISTiledMapServiceLayer("http://server.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer");
    map.addLayer(tiledMapServiceLayer);
});
}

 方法二：

//全局变量
   var basemap1 ;


function getlsLayer(){    
  dojo.addOnLoad(function(){      
    basemap1 = new esri.layers.ArcGISDynamicMapServiceLayer("http://mapservice.agrolib.com/ArcGIS/rest/services/wl_ChinaBasicMap/MapServer");
    map.addLayer(basemap1);
   });      
}

function lsClearClick(){//removerlsLayer(){
   dojo.addOnLoad(function(){
     map.reorderLayer(basemap1);
  }); 
}