Extjs动态加载树

var treePanel;
var treeStore;

//树
var ReadyFun = function(){
 treeStore= Ext.create('Ext.data.TreeStore', {
  proxy : {
         type: 'ajax',
         url: 'index?.sw=groupManagerWidget&.sm=getData',//加载树节点的control
         reader: {
             type : 'json',
             root : 'r',
         }
     },
     root: {
      id : 'rootNode',
         text : 'tree',
         expanded : true
        },
     listeners : {
      beforeexpand : function(node, eOpts){
       Ext.apply(this.proxy.extraParams, {
           groupId : (node.data['id'] == 'rootNode' ? '' : node.data['id']),
           identity : node.raw ? node.raw['flag'] : node.data['flag']
    });
      }
  }
 });
 treePanel=Ext.create('Ext.tree.Panel', {
     title: '树,
     height: 600,
     store: treeStore,
     rootVisible : false,
     useArrows : true,
     listeners : {
         itemclick : function(view , record , item , index , e , eOpts){
    if(record.isExpanded()){
     record.collapse();
    }else{
     record.expand();
    }
    treeNodeClickPage();
   }
     },
     renderTo: tree_div //树显示位置
 });
};
Ext.onReady(ReadyFun);