SecretPage page tap - solved by Simon Lightfoot on #HumpdayQandA - 6th November 2024 :: https://www.youtube.com/watch?v=txmWGhgPKuU

main.dart

// Please solve this one.
//
// If I tap on any one of the eight areas app navigate to “PageTwo()”
//
// If I tap on four of the areas simultaneous
// (I use four fingers to tap with), I want to navigate the “SecretPage()“.
//
// Lets pick “One”, “Two”, “Five” and “Six” as the as the secrete tap areas.

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';

const pageTwo = '/pagetwo';
const secretPage = '/secretpage';

class ButtonState {
  ButtonState({
    required this.navigatorKey,
    required this.magicButtons,
  });

  final GlobalKey<NavigatorState> navigatorKey;

  final Set<int> magicButtons;
  final _buttonsPressed = <int>{};

  void buttonDown(int id) {
    // print('down $id');
    _buttonsPressed.add(id);
    // check if magic happened
    if (setEquals(_buttonsPressed, magicButtons)) {
      final navigator = navigatorKey.currentState!;
      navigator.push(SecretPage.route());
    }
  }

  void buttonUp(int id) {
    // print('up $id');
    final navigator = navigatorKey.currentState!;
    navigator.push(PageTwo.route());
    _buttonsPressed.remove(id);
  }

  void buttonCancel(int id) {
    // print('cancel $id');
    _buttonsPressed.remove(id);
  }
}

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

class MyApp extends StatefulWidget {
  const MyApp({super.key});

  static ButtonState buttonStateOf(BuildContext context) {
    return context.findAncestorStateOfType<_MyAppState>()!._buttonState;
  }

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  final _navigatorKey = GlobalKey<NavigatorState>();
  late final _buttonState = ButtonState(
    navigatorKey: _navigatorKey,
    magicButtons: {1, 2, 5, 6},
  );

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      navigatorKey: _navigatorKey,
      title: 'Touch Four',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      home: const MyHomePage(title: 'Touch Four'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        title: Text(widget.title),
      ),
      body: const Center(
        child: Column(
          children: <Widget>[
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceEvenly,
              children: [
                TouchArea(id: 1, name: 'One'),
                TouchArea(id: 2, name: 'Two'),
              ],
            ),
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceEvenly,
              children: [
                TouchArea(id: 3, name: 'Three'),
                TouchArea(id: 4, name: 'Four'),
              ],
            ),
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceEvenly,
              children: [
                TouchArea(id: 5, name: 'Five'),
                TouchArea(id: 6, name: 'Six'),
              ],
            ),
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceEvenly,
              children: [
                TouchArea(id: 7, name: 'Seven'),
                TouchArea(id: 8, name: 'Eight'),
              ],
            ),
          ],
        ),
      ),

      // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

class TouchArea extends StatefulWidget {
  const TouchArea({
    required this.id,
    required this.name,
    super.key,
  });

  final int id;
  final String name;

  @override
  State<TouchArea> createState() => _TouchAreaState();
}

class _TouchAreaState extends State<TouchArea> {
  @override
  Widget build(BuildContext context) {
    return InkWell(
      onTapDown: (_) {
        MyApp.buttonStateOf(context).buttonDown(widget.id);
      },
      onTapUp: (_) {
        MyApp.buttonStateOf(context).buttonUp(widget.id);
      },
      onTapCancel: () {
        MyApp.buttonStateOf(context).buttonCancel(widget.id);
      },
      child: Padding(
        padding: const EdgeInsets.all(8.0),
        child: SizedBox(
          width: 100,
          height: 40,
          child: DecoratedBox(
            decoration: BoxDecoration(
              border: Border.all(color: Colors.black),
            ),
            child: Padding(
              padding: const EdgeInsets.all(8.0),
              child: Center(
                child: Text(widget.name),
              ),
            ),
          ),
        ),
      ),
    );
  }
}

class PageTwo extends StatelessWidget {
  const PageTwo._();

  static Route<void> route() {
    return MaterialPageRoute(
      builder: (context) => const PageTwo._(),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Page Two'),
      ),
      body: const Center(
        child: Text('Page Two'),
      ),
    );
  }
}

class SecretPage extends StatelessWidget {
  const SecretPage._();

  static Route<void> route() {
    return MaterialPageRoute(
      builder: (context) => const SecretPage._(),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Secret Page'),
      ),
      body: const Center(
        child: Text('Secret Page'),
      ),
    );
  }
}