late initialize a field with ref.watch

[AlwinFassbender]

Hi everyone, assuming I have a stateful widget like this

class ExampleWidget extends ConsumerStatefulWidget {
  const ExampleWidget();

  @override
  ConsumerState<ExampleWidget> createState() => ExampleWidgetState();
}

Now it would be possible to initialize a field in this way.

class ExampleWidgetState extends ConsumerState<ExampleWidget> {

  late final _provider = ref.watch(exampleProvider);

  @override
  Widget build(BuildContext context) {
  
    // assume _provider is used here
    return const Placeholder();
  }
}

Is this okay, or do i have to declare a final provider = ref.watch(exampleProvider) inside the build method? Thanks in advance!

[rrousselGit]

Watch your provider in the build method. You shouldn't use it like this.

[eximius313]

@rrousselGit can it be used like this:

class _MyState extends ConsumerState<MyScreen> {
  late final MyService _myService;

  @override
  void initState() {
    super.initState();
    _myService = ref.read<MyService>(myServiceProvider);
  }

...
}

?

the Service doesn't change, so I don't want to read it at each rebuild

[vasilich6107]

any guidance on why it should not be used like that?