Focusable Action Detector

main.dart

import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/services.dart';

void main() {
  runApp(MaterialApp(home: FAD()));
}

class FAD extends StatefulWidget {
  FAD({Key key}) : super(key: key);
  @override
  _FADState createState() => _FADState();
}

class _FADState extends State<FAD> {
  Map<LogicalKeySet, Intent> _shortcutMap;
  Map<Type, Action<Intent>> _actionMap;
  MouseCursor _mouseCursor;

  @override
  void initState() {
    super.initState();
    _mouseCursor = SystemMouseCursors.basic;
    _shortcutMap = <LogicalKeySet, Intent>{
      LogicalKeySet(LogicalKeyboardKey.keyP):
          const _ShowSecretMessageIntent.P(),
      LogicalKeySet(LogicalKeyboardKey.keyL):
          const _ShowSecretMessageIntent.L(),
      LogicalKeySet(LogicalKeyboardKey.keyA):
          const _ShowSecretMessageIntent.A(),
      LogicalKeySet(LogicalKeyboardKey.keyT):
          const _ShowSecretMessageIntent.T(),
      LogicalKeySet(LogicalKeyboardKey.keyF):
          const _ShowSecretMessageIntent.F(),
      LogicalKeySet(LogicalKeyboardKey.keyO):
          const _ShowSecretMessageIntent.O(),
      LogicalKeySet(LogicalKeyboardKey.keyR):
          const _ShowSecretMessageIntent.R(),
      LogicalKeySet(LogicalKeyboardKey.keyM):
          const _ShowSecretMessageIntent.M(),
    };

    _actionMap = <Type, Action<Intent>>{
      _ShowSecretMessageIntent: CallbackAction<_ShowSecretMessageIntent>(
        onInvoke: _actionHandler,
      ),
    };
  }

  List<Widget> children = [
    Expanded(
      child: Focus(
        autofocus: true,
        child: Container(
          color: Colors.red,
          child: Text('Press P'),
        ),
      ),
    ),
  ];

  void _actionHandler(_ShowSecretMessageIntent intent) {
    switch (intent.type) {
      case _SecretMessageType.P:
        setState(() {
          children.add(
            Expanded(
              child: Container(
                color: Colors.orange,
                child: Text('Press L'),
              ),
            ),
          );
        });
        break;
      case _SecretMessageType.L:
        setState(() {
          children.add(
            Expanded(
              child: Container(
                color: Colors.yellow,
                child: Text('Press A'),
              ),
            ),
          );
        });
        break;
      case _SecretMessageType.A:
        setState(() {
          children.add(
            Expanded(
              child: Container(
                color: Colors.green,
                child: Text('Press T'),
              ),
            ),
          );
        });
        break;
      case _SecretMessageType.T:
        setState(() {
          children.add(
            Expanded(
              child: Container(
                color: Colors.blue,
                child: Text('Press F'),
              ),
            ),
          );
        });
        break;
      case _SecretMessageType.F:
        setState(() {
          children.add(
            Expanded(
              child: Container(
                color: Colors.indigo,
                child: Text('Press O'),
              ),
            ),
          );
        });
        break;
      case _SecretMessageType.O:
        setState(() {
          children.add(
            Expanded(
              child: Container(
                color: Colors.pink,
                child: Text('Press R'),
              ),
            ),
          );
        });
        break;
      case _SecretMessageType.R:
        setState(() {
          children.add(
            Expanded(
              child: Container(
                color: Colors.white,
                child: Text('Press M'),
              ),
            ),
          );
        });
        break;
      case _SecretMessageType.M:
        setState(() {
          children.add(
            Expanded(
              child: Container(
                color: Colors.black,
                child: Text('Done'),
              ),
            ),
          );
        });
        break;
    }
  }

  @override
  Widget build(BuildContext context) {
    return FocusableActionDetector(
      actions: _actionMap,
      shortcuts: _shortcutMap,
      mouseCursor: _mouseCursor,
      child: Scaffold(
        appBar: AppBar(
          title: const Text('Focusable Action Detector'),
          actions: [
            IconButton(
              icon: Icon(Icons.filter_1),
              onPressed: () {
                setState(() {
                  _mouseCursor = SystemMouseCursors.basic;
                });
              },
            ),
            IconButton(
              icon: Icon(Icons.filter_2),
              onPressed: () {
                setState(() {
                  _mouseCursor = SystemMouseCursors.text;
                });
              },
            ),
            IconButton(
              icon: Icon(Icons.filter_3),
              onPressed: () {
                setState(() {
                  _mouseCursor = SystemMouseCursors.click;
                });
              },
            ),
            IconButton(
              icon: Icon(Icons.filter_4),
              onPressed: () {
                setState(() {
                  _mouseCursor = SystemMouseCursors.forbidden;
                });
              },
            ),
            IconButton(
              icon: Icon(Icons.filter_5),
              onPressed: () {
                setState(() {
                  _mouseCursor = SystemMouseCursors.grab;
                });
              },
            ),
            IconButton(
              icon: Icon(Icons.filter_6),
              onPressed: () {
                setState(() {
                  _mouseCursor = SystemMouseCursors.grabbing;
                });
              },
            ),
            IconButton(
              icon: Icon(Icons.filter_7),
              onPressed: () {
                setState(() {
                  _mouseCursor = SystemMouseCursors.none;
                });
              },
            ),
          ],
        ),
        body: Column(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: children,
        ),
      ),
    );
  }
}

class _ShowSecretMessageIntent extends Intent {
  const _ShowSecretMessageIntent({@required this.type});

  const _ShowSecretMessageIntent.P() : type = _SecretMessageType.P;

  const _ShowSecretMessageIntent.L() : type = _SecretMessageType.L;

  const _ShowSecretMessageIntent.A() : type = _SecretMessageType.A;

  const _ShowSecretMessageIntent.T() : type = _SecretMessageType.T;

  const _ShowSecretMessageIntent.F() : type = _SecretMessageType.F;

  const _ShowSecretMessageIntent.O() : type = _SecretMessageType.O;

  const _ShowSecretMessageIntent.R() : type = _SecretMessageType.R;

  const _ShowSecretMessageIntent.M() : type = _SecretMessageType.M;

  final _SecretMessageType type;
}

enum _SecretMessageType {
  P,
  L,
  A,
  T,
  F,
  O,
  R,
  M,
}