ERROR: ANDROID_SDK_ROOT is undefined
Emulator: emulator: ERROR: This AVD's configuration is missing a kernel file! Please ensure the file "kernel-ranchu" is in the same location as your system image.
Emulator: emulator: ERROR: ANDROID_SDK_ROOT is undefined
Emulator: Process finished with exit code 1
第一步：确保你选择的cpu架构的系统映像已经下载，我之前用的是x86镜像，现在改成armeabi-v7a，所以在它前面打上勾，下面的x86去掉勾，apply。
invalidate caches/restart 之后还报错的话，进行第二步：
进入到这个目录：C:\Users\wadew\AppData\Local\Android\Sdk\system-images
把google_apis下面的kernel-ranchu复制到default文件夹下面
参考文章：
https://lengerrong.blogspot.com/2017/04/error-this-avds-configuration-is.html