遇到问题 Cannot run with sound null safety
flutter sdk 版本升级到2.0或者更高的版本后，运行之前的代码会报错，比如：
Error: Cannot run with sound null safety, because the following dependencies
don't support null safety:
- package:flutter_swiper
- package:flutter_page_indicator
- package:transformer_page_view
For solutions, see https://dart.dev/go/unsound-null-safety
FAILURE: Build failed with an exception.
上面的问题是，这些包不支持 safety模式。我们可以在运行的时候添加--no-sound-null-safety
解决方案：
run
flutter run --no-sound-null-safety
build
flutter build apk --no-sound-null-safety
