adv建立，start
建adv成功后，start，出現ANDROID_SDK_ROOT is undefined
Starting emulator for AVD 'lgh'
emulator: ERROR: This AVD's configuration is missing a kernel file! Please ensure the file "kernel-qemu" is in the same location as your system image.
emulator: ERROR: ANDROID_SDK_ROOT is undefined
2018-04-21
AVD缺少核心文件，出現emulator: ERROR:This AVD's configuration is missing a kernel file!!的原因是在你的sdk下缺少相應的kernel-qemu文件。
解決方法試試進入Android SDK Manager，查看相應AVD的Packages ，缺少X86文件夾就下載Intel x86 Atom System Image缺少armeabi-v7a文件夾就下載ARM EABI v7a System Image下載完成就OK 了！