Solution for https://gist.github.com/hillelcoren/d3c5e27b9e52f9f8560f87ca67cbf751: changing themes on a Flutter Redux without AppBuilder widget

main.dart

import 'package:flutter/material.dart';
import 'package:flutter_redux/flutter_redux.dart';
import 'package:redux/redux.dart';

void main() {
  final store = Store<AppState>(
    reducer,
    distinct: true,
    initialState: AppState(enableDarkMode: false),
  );

  runApp(StoreProvider<AppState>(
    store: store,
    child: MyApp(),
  ));
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return StoreConnector<AppState, bool>(
      distinct: true,
      converter: (store) => store.state.enableDarkMode,
      builder: (_, bool enableDarkMode) {
        return MaterialApp(
          theme: ThemeData(
            brightness: enableDarkMode ? Brightness.dark : Brightness.light,
          ),
          home: Scaffold(
            appBar: AppBar(
              title: Text('Test Redux App'),
            ),
            body: SettingsView(),
          ),
        );
      },
    );
  }
}

class SettingsView extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return StoreBuilder( // Would use a StoreConnector & ViewModel in the real world
      builder: (BuildContext context, Store<AppState> store) {
        final state = store.state;
        return SwitchListTile(
          title: Text('Dark Mode'),
          value: state.enableDarkMode,
          onChanged: (value) {
            store.dispatch(UpdateDarkMode(enable: !state.enableDarkMode));
          },
          secondary: Icon(Icons.settings),
        );
      },
    );
  }
}

// Redux
class AppState {
  AppState({@required this.enableDarkMode});
  bool enableDarkMode;
}

class UpdateDarkMode {
  UpdateDarkMode({@required this.enable});
  final bool enable;
}

AppState reducer(AppState state, dynamic action) {
  if (action is UpdateDarkMode) {
    return AppState(
      enableDarkMode: action.enable,
    );
  }

  return state;
}