Counter Example App using StateX v. 4.7

statex_counter_app.dart

import 'package:flutter/material.dart';

import 'package:state_extended/state_extended.dart';

/// Pass the boolean true take make this humble example app more efficient.
void main() => runApp(const StateXCounterPage(useInherited: false));

class StateXCounterPage extends StatefulWidget {
  const StateXCounterPage({
    super.key,
    this.useInherited,
    this.title = 'Flutter Demo Home Page',
  });
  // Fields in a StatefulWidget should always be "final".
  final bool? useInherited;
  final String title;
  @override
  //ignore: no_logic_in_create_state
  State createState() => _StateXCounterPageState(useInherited);
}

/// Instead of the useInherited parameter, use the StateIn class
//class _StateXCounterPageState extends StateIn<StateXCounterPage> {
class _StateXCounterPageState extends StateX<StateXCounterPage> {
  _StateXCounterPageState([useInherited = true])
      : super(controller: YourController(), useInherited: useInherited) {
    con = controller as YourController;
  }
  late YourController con;

  @override
  Widget buildIn(BuildContext context) => MaterialApp(
        home: Scaffold(
          appBar: AppBar(
            title: Text(widget.title),
          ),
          body: Center(
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: <Widget>[
                const Text('You have pushed the button this many times:'),
                state(
                  (context) => Text(
                    '${con.data}',
                    style: Theme.of(context).textTheme.headlineMedium,
                  ),
                ),
              ],
            ),
          ),
          floatingActionButton: FloatingActionButton(
            onPressed: con.onPressed,
            tooltip: 'Increment',
            child: const Icon(Icons.add),
          ),
        ),
      );
}

class YourController extends StateXController {
  // Using a factory constructor on Controllers and implementing the Singleton design pattern
  factory YourController() => _this ??= YourController._();
  YourController._() : _model = _Model();
  static YourController? _this;

  final _Model _model;

  int get data => _model.integer;

  void onPressed() {
    // Allow only updating one widget improving performance
    if (state!.useInherited) {
      _model._incrementCounter();
      notifyClients(); // The state() function is then called
    } else {
      setState(() => _model._incrementCounter());
    }
  }
}

class _Model {
  int get integer => _integer;
  int _integer = 0;
  int _incrementCounter() => ++_integer;
}