之前的建议方法是把在xxx.info.plist文件中把
icon already includes gloss and bevel effects 设置YES
在Xcode5下，反复实现不成功，今天终于找到解决方案，如果使用xcassets设置方法，需要选择iOS icon is pre-rendered 的选择框，如图
xcod5在iOS5下白图标问题，
http://iphonedevsdk.com/forum/iphone-sdk-development/115604-ipad-icon-appearing-white-on-ios-5-using-xcode-5-0.html
http://stackoverflow.com/questions/19220082/support-of-ios-5-0-icons-with-xcode-5