遇到問題 Cannot run with sound null safety

flutter sdk 版本升級到2.0或者更高的版本后，運行之前的代碼會報錯，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.

上面的問題是，這些包不支持 safety模式。我們可以在運行的時候添加--no-sound-null-safety

解決方案：

 run
 flutter run --no-sound-null-safety

 build
 flutter build apk --no-sound-null-safety