出现No URL set!

{"button":[{"name":"菜单一","type":"click","key":"item1"},{"name":"\u83dc\u5355\u4e8c","sub_button":[{"name":"歌曲","type":"click","key":"songs"},{"name":"电影","type":"view","url":"http:\/\/www.baidu.com"}]}]} No URL set! 为什么会出现No URL set!