AndroidStudio导入了jar包但是仍然找不到类

• 方法一：
  菜单栏file->invalidate caches/restart -> invalidate and restart
• 方法二：
  
  • Something went wrong in incremental build system. One of this should help:
    
    1. Menu Build -> Rebuild project
    2. Delete folder /build
    3. Close Android Studio, delete /build folder
    4. Right click on your project -> “Open module settings” ->
       Dependencies tab -> check if Export is checked for your library