Extjs 表格分组 grid grouping

Ext.onReady(function(){
	Ext.QuickTips.init();  
	Ext.form.Field.prototype.msgTarget='side';
	var itemsPerPage=10;
	var store1=Ext.create('Ext.data.Store',{
		   storeId:'gridStore1',
		   fields:['Id','Title','Time','Author'],
		   pageSize: itemsPerPage,
		   autoLoad:true,
		   groupField:'Author',//制定grid分组的依据字段
		   data:{'items':[
		   	{Id:'001',Title:'wwww',Time:'2012-8-8',Author:'张三'},
		   	{Id:'002',Title:'wwww',Time:'2012-8-8',Author:'张三'},
		   	{Id:'003',Title:'wwww',Time:'2012-8-8',Author:'李四'},
		   	{Id:'004',Title:'wwww',Time:'2012-8-8',Author:'李四'},
		   	{Id:'005',Title:'wwww',Time:'2012-8-8',Author:'李四'},
		   	{Id:'006',Title:'wwww',Time:'2012-8-8',Author:'张三'},
		   	]},
		   	proxy:{
			   	  type:'memory',
			   	  reader:{
			   	    type:'json',
			   	    root:'items',
			   	    totalProperty:'counts'
			   	  }
			}
		});
	
	//显示信息的grid    
	var gridPanel1=Ext.create('Ext.grid.Panel',{
		store:store1,
	    selType:'rowmodel',
	    renderTo:'content',
	    viewConfig:{
	       columnsText: '列',
           sortAscText: '升序',
           sortDescText: '降序'
	    },
	    features:[
	         Ext.create("Ext.grid.feature.Grouping",{
	        	 groupByText:'字段分组',
	        	 showGroupsText:'显示分组',
	        	 groupHeaderTpl:'作者：{name}({rows.length})',
	        	 startCollapsed:false
	        	         	 
	         })
	              
	              
	    ],
	    
	    columns:[
	    {header:'序号',dataIndex:'Id'},
	    {header:'标题',dataIndex:'Title',flex:1},
	    {header:'时间',dataIndex:'Time'},
	    {header:'时间',dataIndex:'Author'}
	    ],
	    bbar:Ext.create('Ext.toolbar.Paging', {
				    	store:store1,
			            pageSize : 2,  
			            emptyMsg : "没有数据显示！",   
						displayInfo : true,   
						displayMsg : '显示 {0} - {1} 共 {2} 条',   
						beforePageText : "页码 ",   
						afterPageText : "共 {0} 页",   
						firstText : "首页",   
						lastText : "末页",   
						nextText : "下一页",   
						prevText : "上一页",   
						refreshText : "刷新"
			          })
	});
	
});

新增事件  groupclick，groupdbclick，groupcontextmenu，groupexpand，groupcollapse