Issue
Now I’m working in flutter project.
I need to add //@dart=2.9 in dart file.
But i got run time error. Like A library can’t opt out of null safety by default,when using sound null safety.
How can i add it on dart file?
Solution
add it at the top of main.dart.
then run
$ flutter clean
$ flutter pub get
if this does not work,check this https://dart.dev/null-safety/migration-guide
Answered By – takudzw_M
Answer Checked By – Senaida (FlutterFixes Volunteer)