Setting provider value in FutureBuilder

Simply remove the notifyListeners(); from the code. I encountered this error and that was what I did to resolve the issue.

I have encountered a problem similar to yours when using the provider. My solution is to add WidgetsBinding.instance.addPostFrameCallback() when getting the data.

That exception arises because you are synchronously modifying a widget from its descendants.

This is bad, as it could lead to an inconsistent widget tree. Some widget. may be built widgets using the value before mutation, while others may be using the mutated value.

The solution is to remove the inconsistency. Using ChangeNotifierProvider, there are usually 2 scenarios:

• The mutation performed on your ChangeNotifier is always done within the same build than the one that created your ChangeNotifier.

  In that case, you can just do the call directly from the constructor of your ChangeNotifier:

  class MyNotifier with ChangeNotifier {
    MyNotifier() {
      // TODO: start some request
    }
  }
  

• The change performed can happen "lazily" (typically after changing page).

  In that case, you should wrap your mutation in an addPostFrameCallback or a Future.microtask:

  class Example extends StatefulWidget {
    @override
    _ExampleState createState() => _ExampleState();
  }
  
  class _ExampleState extends State<Example> {
    MyNotifier notifier;
  
    @override
    void didChangeDependencies() {
      super.didChangeDependencies();
      final notifier = Provider.of<MyNotifier>(context);
  
      if (this.notifier != notifier) {
        this.notifier = notifier;
        Future.microtask(() => notifier.doSomeHttpCall());
      }
    }
  
    @override
    Widget build(BuildContext context) {
      return Container();
    }
  }