How to build APK with no sound null safety

Question

I can run an app in release mode on my phone with passing flag --no-sound-null-safety --release, but neither flutter build apk --enable-experiment=non-nullable nor flutter build apk --no-sound-null-safety nor flutter build apk --enable-experiment=non-nullable --no-sound-null-safety will work

Solution 1

It was only necessary to use additional comment // @dart=2.9 before all imports in main.dart so it could run without any flags

So main.dart should look like this:

// @dart=2.9
import 'package:flutter/gestures.dart';
import 'package:flutter/widgets.dart';
import '../init.dart';

Future<void> main() async {
  GestureBinding.instance?.resamplingEnabled = true;
  WidgetsFlutterBinding.ensureInitialized();
  await init();
  runApp(MyApp());
}

Any other .dart files don't require annotating them

P.S. make sure you updated pubspec.yaml for using Dart 2.12:

environment:
  sdk: '>=2.12.0-0.0 <3.0.0'

Solution 2

Just do this on your terminal

flutter build apk --split-per-abi --no-sound-null-safety

Or

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

Solution 3

we can try this,

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

or by adding in main.dart , 1st Line

 // @dart=2.9

Solution 4

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

View more solutions

Comments

[Void]

It does not fixes the problem, as it only states that the file does not supports null safety.

[Andrey Gritsay]

I don'y see any problem as main.dart should be used only as an entry point such as runApp(MyApp()) and actual MyApp() widget could be in another file

[Void]

But this other file would still have the problem. If it uses null-safety

[Andrey Gritsay]

Nope. My full project uses null-safety and only main.dart doesn't and everything works as expected

[Void]

Are you sure? Because the doc say otherwise : 'Add a language version comment to the top of any Dart files that you don’t want to consider during your current migration:' So, other file would still be checked for null safety

[Andrey Gritsay]

Yes, I'm sure because otherwise I wouldn't mark it as an answer. Before annotating flutter build apk produced a lot of errors related to null checks

[Tin Man]

// @dart=2.9 marks the whole file to be used with Dart 2.9. If only a few of the libraries used as imports are nullable, but the rest of the file has been adjusted for null safety (and uses e.g. the nullability character ?), this won't work.

[Andrey Gritsay]

@TinMan Everything works if you put everything out of main.dart and leave it with only runApp() function

[Dolphin]

it did not works when the flutter version is 2.2.x when build ios pakcage.@Adam Musa

[Adam Musa]

In flutter 2.x null safety is enabled by default. So to solve this you have to downgrade the sdk version of dart to 2.7.x. And you change the way of coding when you bring your sdk back to 2.7.x because it does not support the philosophy of sdk> = 2.10.x

[Rebar]

Not working for 2022 with Flutter 2.10.0