An example of using intents and actions API

main.dart

import 'package:flutter/material.dart';
import 'dart:async';
import 'package:meta/meta.dart';

const Color darkBlue = Color.fromARGB(255, 18, 32, 47);

void main() {
  runApp(
    const MyApp(),
  );
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.dark().copyWith(
        scaffoldBackgroundColor: darkBlue,
      ),
      debugShowCheckedModeBanner: false,
      home: const Scaffold(
        body: Center(
          child: MyWidget(),
        ),
      ),
    );
  }
}

class MyWidget extends StatelessWidget {
  const MyWidget({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return ModelInh(
      model: Model(),
      child: Builder(builder: (context) {
        final model = ModelInh.of(context).model;
        return Actions(
          actions: {
            ModifyIntent: CountAction(model),
          },
          child: Builder(
            builder: (context) {
              return StreamBuilder<int>(
                initialData: 0,
                stream: model.stream,
                builder: (context, d) {
                  return Column(children: [
                    Text('Count: ${d.data}'),
                    TextButton(
                      child: const Text('Add'),
                      onPressed: () => Actions.invoke(
                        context,
                        ModifyIntent(d.data! + 1),
                      ),
                    )
                  ]);
                },
              );
            },
          ),
        );
      }),
    );
  }
}

class ModelInh extends InheritedWidget {
  const ModelInh({
    Key? key,
    required Widget child,
    required this.model,
  }) : super(key: key, child: child);

  final Model model;

  static ModelInh of(BuildContext context) {
    ModelInh? inh;
    final result =
        context.getElementForInheritedWidgetOfExactType<ModelInh>()?.widget;
    inh = result is ModelInh ? result : null;
    assert(inh != null, 'No Model found in context');
    return inh ?? _notInScope();
  }

  @alwaysThrows
  static Never _notInScope() => throw 'No Model found in context';

  @override
  bool updateShouldNotify(ModelInh oldWidget) {
    return false;
  }
}

class Model {
  Model();

  final _controller = StreamController<int>.broadcast();

  Stream<int> get stream => _controller.stream;

  void setCount(int c) {
    _controller.add(c);
  }
}

class ModifyIntent extends Intent {
  const ModifyIntent(this.count);

  final int count;
}

class CountAction extends Action<ModifyIntent> {
  CountAction(this.model);

  final Model model;

  @override
  void invoke(covariant ModifyIntent intent) {
    model.setCount(intent.count);
  }
}