Extjs动态设置tbar

实现按btn2按钮时,将btn1,btn2去掉,更新为新的tbar ,t

var panel = new Ext.Panel({
        title:'toolbar-changebar',
                  renderTo:Ext.getBody(),
        tbar:[{
            text:'btn1',
            handler:function (){
                alert("btn1");
            }
        },{
            text:'btn2',
            handler:function (){
                 changeBar ();
            }
        }]
    });

    function changeBar (){
        var t=[{text:'abc'},{text:'aab'}];
        var tbItem = panel.getTopToolbar();
        tbItem.removeAll();
            tbItem.add(t);
        panel.doLayout();
    }