flutter/examples/api/lib/widgets/actions/focusable_action_detector.0.dart

// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Template: dev/snippets/config/templates/stateful_widget_material.tmpl
//
// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
// of samples, and may be ignored if you are just exploring the sample.

// Flutter code sample for FocusableActionDetector
//
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// This example shows how keyboard interaction can be added to a custom control
// that changes color when hovered and focused, and can toggle a light when
// activated, either by touch or by hitting the `X` key on the keyboard when
// the "And Me" button has the keyboard focus (be sure to use TAB to move the
// focus to the "And Me" button before trying it out).
//
// This example defines its own key binding for the `X` key, but in this case,
// there is also a default key binding for [ActivateAction] in the default key
// bindings created by [WidgetsApp] (the parent for [MaterialApp], and
// [CupertinoApp]), so the `ENTER` key will also activate the buttons.

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//***************************************************************************

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

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//****************************************************************************

void main() => runApp(const MyApp());

/// This is the main application widget.
class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  static const String _title = 'Flutter Code Sample';

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      title: _title,
      home: MyStatefulWidget(),
    );
  }
}

//*****************************************************************************
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class FadButton extends StatefulWidget {
  const FadButton({
    Key? key,
    required this.onPressed,
    required this.child,
  }) : super(key: key);

  final VoidCallback onPressed;
  final Widget child;

  @override
  State<FadButton> createState() => _FadButtonState();
}

class _FadButtonState extends State<FadButton> {
  bool _focused = false;
  bool _hovering = false;
  bool _on = false;
  late final Map<Type, Action<Intent>> _actionMap;
  final Map<ShortcutActivator, Intent> _shortcutMap =
      const <ShortcutActivator, Intent>{
    SingleActivator(LogicalKeyboardKey.keyX): ActivateIntent(),
  };

  @override
  void initState() {
    super.initState();
    _actionMap = <Type, Action<Intent>>{
      ActivateIntent: CallbackAction<Intent>(
        onInvoke: (Intent intent) => _toggleState(),
      ),
    };
  }

  Color get color {
    Color baseColor = Colors.lightBlue;
    if (_focused) {
      baseColor = Color.alphaBlend(Colors.black.withOpacity(0.25), baseColor);
    }
    if (_hovering) {
      baseColor = Color.alphaBlend(Colors.black.withOpacity(0.1), baseColor);
    }
    return baseColor;
  }

  void _toggleState() {
    setState(() {
      _on = !_on;
    });
  }

  void _handleFocusHighlight(bool value) {
    setState(() {
      _focused = value;
    });
  }

  void _handleHoveHighlight(bool value) {
    setState(() {
      _hovering = value;
    });
  }

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: _toggleState,
      child: FocusableActionDetector(
        actions: _actionMap,
        shortcuts: _shortcutMap,
        onShowFocusHighlight: _handleFocusHighlight,
        onShowHoverHighlight: _handleHoveHighlight,
        child: Row(
          children: <Widget>[
            Container(
              padding: const EdgeInsets.all(10.0),
              color: color,
              child: widget.child,
            ),
            Container(
              width: 30,
              height: 30,
              margin: const EdgeInsets.all(10.0),
              color: _on ? Colors.red : Colors.transparent,
            ),
          ],
        ),
      ),
    );
  }
}

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//*****************************************************************************

/// This is the stateful widget that the main application instantiates.
class MyStatefulWidget extends StatefulWidget {
  const MyStatefulWidget({Key? key}) : super(key: key);

  @override
  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
}

/// This is the private State class that goes with MyStatefulWidget.
class _MyStatefulWidgetState extends State<MyStatefulWidget> {
//********************************************************************
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  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('FocusableActionDetector Example'),
      ),
      body: Center(
        child: Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Padding(
              padding: const EdgeInsets.all(8.0),
              child:
                  TextButton(onPressed: () {}, child: const Text('Press Me')),
            ),
            Padding(
              padding: const EdgeInsets.all(8.0),
              child: FadButton(onPressed: () {}, child: const Text('And Me')),
            ),
          ],
        ),
      ),
    );
  }

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//********************************************************************

}