在混淆我的应用程序时,我收到以下错误.如何在build.xml中定义输出jar？
[java] Shrinking...
[java] java.io.IOException: The output jar is empty. Did you specify the proper '-keep' options?
[java] at proguard.shrink.Shrinker.execute(Shrinker.java:148)
[java] at proguard.ProGuard.shrink(ProGuard.java:294)
[java] at proguard.ProGuard.execute(ProGuard.java:100)
[java] at proguard.ProGuard.main(ProGuard.java:499)