CODEWITHSUNDEEP
flutterriverpodriverpod-generatorriverpod-annotation
Christian
Christian

Reputation: 1068

"Bad state: Tried to read the state of an uninitialized provider" with riverpod while listening to futureprovider

I have this generated notifier that should rebuild when the data changes without loosing its reference to a previously selected object on rebuild.

@Riverpod(keepAlive:true)
Future<List<MyModel>> modelList (ModelListRef ref) {
    return ref.watch(modelRepositoryProvider).getModels();
}

@Riverpod(keepAlive:true)
class MyController extends _$MyController {
  
  @override
  MyModel? build() {
    return ref.watch(modelListProvider).maybeWhen(
      //Accessing this state throws the error                             ↓
      data: (models) => models.singleWhereOrNull((model) => model.id == state?.id),
      orElse: () => null,
    );
  }
  
  @override 
  set state (MyModel value){
    state = value;
   }
}

I am calling

  ref.invalidate(modelListProvider);

after changing data to trigger a rebuild but when I am reading the notifiers state again, I am getting an error:

StateError (Bad state: Tried to read the state of an uninitialized provider)

and the stacktrace leads me to the state of the notifier. How can I fix that?

Upvotes: 3

Views: 2843

Answers (1)

Christian
Christian

Reputation: 1068

This seems to work for now:

@Riverpod(keepAlive:true)
class MyController extends _$MyController {
  
  @override
  MyModel? build() {
   state = null;
   ref.listen(
     modelListProvider,
     (previous, next) {
       next.maybeWhen(
         data: (models) {
           state = models.firstWhereOrNull((model) => model.id == state?.id);
         },
         orElse: (){
           state = null;
         },
       );
     },
     fireImmediately: true,
   );
   return state;
  }
  
  @override 
  set state (MyModel value){
    state = value;
   }
}

Upvotes: 1

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