Strange error with get_it_mixin about get_it_mixin

[esDotDev]

Ya this is just a warning, it should not impact anything. Still it would be nice if this could be patched soon.

[Ruzo]

It's just an unnecessary_non_null_assertion warning in mixin_state.dart. I did a pull request for the fix but then saw that there was already an old one. Mine has updated packages and stuff.

I don't think there are too many users of this package. I'm guessing that's the reason why Thomas is not spending too much time on it.

[thommy66]

I did some more research since this is a showstopper for me.

The impact of this warning / error is as follows:
notifyListeners() does somehow not work. I use it in a Scaffold with a BottomNavigationBar. This requires to detect if the selected (tab)item changes. The build method of the widget is not immediately called. Sometimes it does rebuild after one minute or so!! Really strange.

So I have loaded a very old project which I used to learn how to work with get_it_mixin. That is extremely simple and has no other packages than get_it / get_it_mixin. It uses version 1.5.1. There no error is displayed and notifyListeners() works just fine.

Looks like there is a problem with version 3.1.3. I tried to use an older version like 1.5.1 but that does not work because of dependencies. Also Version 2.0.0 seems to be to old. I also tried 3.1.0 but there the same error is shown. To me this looks like a dependency problem of recent version with latest versions of Android Studio and the Flutter SDK.

This is my pubspec.yaml file with the latest version and the error shown above:

dependencies:
  flutter:
    sdk: flutter


  # The following adds the Cupertino Icons font to your application.
  # Use with the CupertinoIcons class for iOS style icons.
  cupertino_icons: ^1.0.2
  bottom_navy_bar: ^6.0.0
  get_it: ^7.2.0
  get_it_mixin: ^3.1.3
  servicestack: ^2.0.0
  font_awesome_flutter: ^9.1.0
  hive: ^2.0.4
  hive_flutter: ^1.1.0
  path_provider: ^2.0.3
  uuid: ^3.0.4
  equatable: ^2.0.3
  intl: ^0.17.0
  tuple: ^2.0.0
  flutter_layout_grid: ^1.0.3
  device_info_plus: ^3.0.1
  network_info_plus: ^2.0.2
  flutter_slidable: ^1.1.0

dev_dependencies:
  flutter_test:
    sdk: flutter

  # The "flutter_lints" package below contains a set of recommended lints to
  # encourage good coding practices. The lint set provided by the package is
  # activated in the `analysis_options.yaml` file located at the root of your
  # package. See that file for information about deactivating specific lint
  # rules and activating additional ones.
  flutter_lints: ^1.0.0
  build_runner: ^2.1.5

I also cleaned the public cache with flutter pub cache clean and then ran flutter pub get to make sure I do not have corrupted stuff in my .pub-cache folder. However this did not help.

I have no idea what else I could try....

[thommy66]

OK, I solved the problem of the changeNotifiers not being registered.

I used get/getX instead of watchOnly. It looks like the listener is registered in watchOnly and not in get.

    // final selectedTab = get<DashboardManager>().selectedTab;  <======  THIS IS WRONG
    final selectedTab = watchOnly((DashboardManager x) => x.selectedTab); <==== THIS IS CORRECT

However, this warning

../../../../Applications/flutter/.pub-cache/hosted/pub.dartlang.org/get_it_mixin-3.1.3/lib/src/mixin_state.dart:495:7: Warning: Operand of null-aware operation '!' has type 'void Function(BuildContext, AsyncSnapshot<R?>, void Function())' which excludes null.
 - 'BuildContext' is from 'package:flutter/src/widgets/framework.dart' ('../../../../Applications/flutter/packages/flutter/lib/src/widgets/framework.dart').
 - 'AsyncSnapshot' is from 'package:flutter/src/widgets/async.dart' ('../../../../Applications/flutter/packages/flutter/lib/src/widgets/async.dart').
      handler!(_element!, watch.lastValue!, watch.dispose);
      ^

remains with the latest Dart/Flutter versions.

[escamoteur]

Guys, really sorry about that I couldn't take care earlier of this.

Indeed @thommy66 get really only gets and does not start to monitor changes.