Unsupported Modules Detected: Compilation is not supported for following modules: WanAndroidClien...

• 问题：

Unsupported Modules Detected: Compilation is not supported for following modules: WanAndroidClient. Unfortunately you can't have non-Gradle Java modules and Android-Gradle modules in one project.

• 说明：
  此问题出现于AndroidStudio中，本人是因为在从Github上克隆项目导入时出现，所有方法都不管用，不管是Rebuild、Clean、InvalidateCache同样是毫无作用。
• 解决方法：File -> Sync Project and Gradle files