Some problems appear after the SDK is downloaded again.
I'll record them on here
1) Use flutter commoned in cmd to stop at pub upgrade all the time
One of the reasons for this promble is that the old sdk path has not been changed
Modify flutter.sdk in the local.properties to the new sdk path in .android directory of the project
2) Process 'command 'D:\DART_SDK_PATH\flutter\bin\flutter.bat'' finished with non-zero exit value 1
The reason for this problems can be founded in Messages.
The problem I ran into was that flutter couldn't access repository.
Add two environment variables
PUB_HOSTED_URL ===== https://pub.flutter-io.cn
FLUTTER_STORAGE_BASE_URL ===== https://storage.flutter-io.cn
3)If want use hot reload in mixed project, can use command flutter attach
hot reload by press R
4）Expected a key while parsing a block mapping.
The reason of this problem is some blank space in the pubspec.yaml