报错：
Failed to rename directory because access was denied. This may be caused by a virus scanner or having a file in the directory open in another application. pub get failed (1; in the directory open in another application.)
解决办法： 打开flutter-io.cn 滑到最底 使用清华大学TUNA协会的镜像！
报错：
A problem occurred evaluating settings 'android'. flutter.sdk not set in local.properties. Expression: (flutterSdkPath != null). Values: flutterSdkPath = null
解决方法： 在Android Studio打开local.properties文件，加上flutter.sdk的目录：
