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_<?php echo $user_languag;?>_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();}},
'<font color="red">提示：双击一行可进行编辑！</font>'
],
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 '<div class="x-grid3-row-expander"> </div>';
},

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(
'<br>  <b>游戏权限:</b> {games}<br><br>',
' <b>下属人员:</b> {users}<br><br>'
)
});

接着载入grid就可以了。