在看官方的例子时候由一个grid实例，在每一行之前有个加号，展开可以显示内容，在实际应用中还是非常有用的，照搬例子的代码，发现老是提示对象不存在，查阅资料后发现是没有加载插件，这里和大家分享下Ext.grid.RowExpander插件的使用，

在看官方的例子时候由一个grid实例，在每一行之前有个加号，展开可以显示内容，在实际应用中还是非常有用的，照搬例子的代码，发现老是提示对象不存在，查阅资料后发现是没有加载插件，这里和大家分享下Ext.grid.RowExpander插件的使用，

首先定义表格grid

 
//生成表格
function makeGrid(){
   return new Ext.grid.GridPanel({
         border:false,
         viewConfig: {
            forceFit:true//加入该选项全屏显示表格且自适应大小，不产生横向滚动条
         },
         buttonAlign :'left',
         region:'center',
         plugins: expander,//定义插件
         loadMask: true,
         store: ds,
         cm: new Ext.grid.ColumnModel([
             expander,//加载插件
             new Ext.grid.RowNumberer(),
             //new Ext.grid.CheckboxSelectionModel(),
             {header:"ID",width:50,sortable:true,dataIndex:'roles_id'},
             {header:"名称", width:100,sortable:false,dataIndex:'roles__name'},
             {header:"类型", width:100,sortable:false,renderer:check,dataIndex:'roles_type'}
            ]),
         //sm:new Ext.grid.CheckboxSelectionModel(),
         //autoExpandColumn:4,
         autoScroll: true,
         tbar: [
            {text:"添加",iconCls:'add_role',handler:newRole},{xtype:'tbseparator'},
            //{text:"删除",iconCls:'del',handler:del},{xtype:'tbseparator'},
             {text:"复制权限",iconCls:'copy',handler:copyRole},{xtype:'tbseparator'},
                {text:"刷新",iconCls:'refresh',handler:function (){ds.reload();}},
            '提示：双击一行可进行编辑！'
         ],
         bbar: new Ext.PagingToolbar({
            pageSize: 50,
            store: ds,
            displayInfo: true,
            displayMsg: '第{0} 到 {1} 条数据 共{2}条',
            emptyMsg: '没有数据'
         })
      });
}

接着在生成表格之前加载插件，插件代码在ext官方论坛找到

 
/*********************************************
           Ext.grid.RowExpander插件
   *********************************************/
   Ext.grid.RowExpander = function(config){
      Ext.apply(this, config);

      this.addEvents({
         beforeexpand : true,
         expand: true,
         beforecollapse: true,
         collapse: true
      });

      Ext.grid.RowExpander.superclass.constructor.call(this);

      if(this.tpl){
         if(typeof this.tpl == 'string'){
            this.tpl = new Ext.Template(this.tpl);
         }
         this.tpl.compile();
      }

      this.state = {};
      this.bodyContent = {};
   };

   Ext.extend(Ext.grid.RowExpander, Ext.util.Observable, {
      header: "",
      width: 20,
      sortable: false,
      fixed:true,
      menuDisabled:true,
      dataIndex: '',
      id: 'expander',
      lazyRender : true,
      enableCaching: true,

      getRowClass : function(record, rowIndex, p, ds){
         p.cols = p.cols-1;
         var content = this.bodyContent[record.id];
         if(!content && !this.lazyRender){
            content = this.getBodyContent(record, rowIndex);
         }
         if(content){
            p.body = content;
         }
         return this.state[record.id] ? 'x-grid3-row-expanded' : 'x-grid3-row-collapsed';
      },

      init : function(grid){
         this.grid = grid;

         var view = grid.getView();
         view.getRowClass = this.getRowClass.createDelegate(this);

         view.enableRowBody = true;

         grid.on('render', function(){
            view.mainBody.on('mousedown', this.onMouseDown, this);
         }, this);
      },

      getBodyContent : function(record, index){
         if(!this.enableCaching){
            return this.tpl.apply(record.data);
         }
         var content = this.bodyContent[record.id];
         if(!content){
            content = this.tpl.apply(record.data);
            this.bodyContent[record.id] = content;
         }
         return content;
      },

      onMouseDown : function(e, t){
         if(t.className == 'x-grid3-row-expander'){
            e.stopEvent();
            var row = e.getTarget('.x-grid3-row');
            this.toggleRow(row);
         }
      },

      renderer : function(v, p, record){
         p.cellAttr = 'rowspan="2"';
         return '

 

';
      },

      beforeExpand : function(record, body, rowIndex){
         if(this.fireEvent('beforeexpand', this, record, body, rowIndex) !== false){
            if(this.tpl && this.lazyRender){
               body.innerHTML = this.getBodyContent(record, rowIndex);
            }
            return true;
         }else{
            return false;
         }
      },

      toggleRow : function(row){
         if(typeof row == 'number'){
            row = this.grid.view.getRow(row);
         }
         this[Ext.fly(row).hasClass('x-grid3-row-collapsed') ? 'expandRow' : 'collapseRow'](row);
      },

      expandRow : function(row){
         if(typeof row == 'number'){
            row = this.grid.view.getRow(row);
         }
         var record = this.grid.store.getAt(row.rowIndex);
         var body = Ext.DomQuery.selectNode('tr:nth(2) div.x-grid3-row-body', row);
         if(this.beforeExpand(record, body, row.rowIndex)){
            this.state[record.id] = true;
            Ext.fly(row).replaceClass('x-grid3-row-collapsed', 'x-grid3-row-expanded');
            this.fireEvent('expand', this, record, body, row.rowIndex);
         }
      },

      collapseRow : function(row){
         if(typeof row == 'number'){
            row = this.grid.view.getRow(row);
         }
         var record = this.grid.store.getAt(row.rowIndex);
         var body = Ext.fly(row).child('tr:nth(1) div.x-grid3-row-body', true);
         if(this.fireEvent('beforcollapse', this, record, body, row.rowIndex) !== false){
            this.state[record.id] = false;
            Ext.fly(row).replaceClass('x-grid3-row-expanded', 'x-grid3-row-collapsed');
            this.fireEvent('collapse', this, record, body, row.rowIndex);
         }
      }
   });

接着定义模板，主要是显示展开的内容，用到Ext.template类

 
expander = new Ext.grid.RowExpander({
        tpl : new Ext.Template(
            '
  游戏权限: {games}

',
            ' 下属人员: {users}

'
        )
});

接着载入grid就可以了。