Ext.define('SimplePanel', {
  extend: 'Ext.panel.Panel',
  alias: ['widget.simplepanel_007','widget.simplepanel_008'],
        title: 'Yeah!'
});

//通过Ext.widget()创建实例
Ext.widget('simplepanel_007',{
  width : 100,
  height : 100
}).render(Ext.getBody());

//通过xtype创建
Ext.widget('simplepanel_007', {
  width : 100,
  items: [
    {xtype: 'simplepanel_008', html: 'Foo'},
    {xtype: 'simplepanel_008', html: 'Bar'}
  ]
}).render(Ext.getBody());