Android的扩展文件库设置

我一直在努力实施失败扩展文件。我已经包括了授权，扩建和外部jar文件示例项目，一切zip文件库似乎是罚款，所有的错误离开。当我运行该程序，但是，我得到一个错误，指出：

I have been trying to implement Expansion files unsuccessfully. I have included the libraries for Licensing, Expansion, and zip files as external jar files to the sample project and everything seems to be fine and all errors go away. When I run the program, however, I get an error that says:

05-22 17：49：05.377：E / AndroidRuntime（10197）：java.lang.NoClassDefFoundError的：com.android.vending.expansion.downloader.R $字符串

"05-22 17:49:05.377: E/AndroidRuntime(10197): java.lang.NoClassDefFoundError: com.android.vending.expansion.downloader.R$string"

和程序崩溃。如何解决这个错误，所以我可以使用测试，然后使用扩展库？

and the program crashes. How do I resolve this error so I can use test and then use the expansion library?

感谢。