Libgdx应用程序无法解决。 SuperJumper类型的层次结构不一致

Question

我正在尝试按照本教程： http://appwarp.shephertz.com/game-development-center/java-multiplayer-libgdx-tutorial/#what-are-we-going-to-do

然而，当我将项目克隆到我的计算机并更换密钥（甚至之前）时，SuperJumperAndroid.java中会弹出这个问题：

Multiple markers at this line
- The type com.badlogic.gdx.Application cannot be resolved. It is indirectly  
referenced from required .class files

- The hierarchy of the type SuperJumperAndroid is inconsistent

和

The type com.badlogic.gdx.Application cannot be resolved. 
It is indirectly referenced from required .class files

快速修复说我应该更新构建路径但是我真的不知道要更新什么。

任何帮助将不胜感激：D 提前致谢