打开AS时出现了Unsupported Modules Detected: Compilation is not supported for following modules: app, KeyboardView. Unfortunately you can’t have non-Gradle Java modules and Android-Gradle modules in one project的错误，解决步骤如下：
（1）关闭as
（2）删除.idea目录
（3）删除app/build目录
（4）重新打开as
from:https://blog.csdn.net/qq_40600379/article/details/106485687