Warning! This package referenced a Flutter repository via the .packages file that is no longer available. The repository from which the 'flutter' tool is currently executing will be used instead. running Flutter tool: D:\flutter\flutter_windows_v1.5.4-hotfix.2-stable\flutter previous reference : D:\flutter\flutter_windows_v1.2.1-stable\flutter This can happen if you deleted or moved your copy of the Flutter repository, or if it was on a volume that is no longer mounted or has been mounted at a different location. Please check your system path to verify that you are running the expected version (run 'flutter --version' to see which flutter is on your path).
这种异常的出现可能是你删除或移动了项目，亦或是修改或删除了flutter sdk的路径
解决办法
把所有的路径修改正确，包括环境变量和项目设置中flutter sdk的路径
