ExtJs4.1中给列表的单元格设置颜色

如：

代码：

{
                                        xtype: 'gridcolumn',
                                        dataIndex: 'summary',
                                        text: '总评价',//'改',
                                        width: 70,
                                        renderer: function(value, metaData, record) {
                                            var index = summaryStore.find('evalValue',value);
                                            if(index != -1) {
                                                var value = summaryStore.getAt(index).get('result');
                                            }
                                            return value;
                                       },
                                        stateId:'qpniRgaProblemInQpni_012'
                                    },
                                    {
                                        xtype: 'gridcolumn',
                                        dataIndex: 'askedDes',
                                        text: gridSummary.qpn.title16,//'问题描述',
                                        width: 130,
                                        editor: {
                                            xtype: 'textfield',
                                            maxLength:100
                                        },
                                        renderer: function(value, metaData, record,store) {
                                           //   me.onRgCellClick(value, metaData, record,store);
                                              
                                              var stage = record.get('rgaStage');
                                              var publishFlag = Ext.getCmp('stageBtn'+stage);
                                              if(publishFlag.isDisabled()){
                                              }else{
                                                   metaData.style='background:#F0F0F0';
                                              }
                                              
                                              if(value != null && value.toString().length > 7) {
                                                metaData.tdAttr = 'data-qtip="' + value + '"';
                                              }
                                            return value;
                                         },
                                         stateId:'qpniRgaProblemInQpni_013'
                                    }