未捕获错误:[Ext。无法创建未识别别名的实例:widget.blogpanel

i am new to sencha touch 2. while i was trying to instantiate after creating a blog view by following instructions from a tutorial.this error "Uncaught Error: [Ext.createByAlias] Cannot create an instance of unrecognized alias: widget.blogpanel" appeared;i am new to sencha touch 2. while i was trying