Flutter 如何在颤振中设置材料按钮的焦点

我希望焦点在“材质”按钮上，这样我就可以按enter键或单击按钮来创建项目

final FocusNode _createButtonFocusNode = new FocusNode();

@override
void initState() {
   FocusScope.of(context).requestFocus(_createButtonFocusNode);
   super.initState();
}
 RawKeyboardListener(
                focusNode: _createButtonFocusNode,
                onKey: (RawKeyEvent event) {
                  if (event.logicalKey == LogicalKeyboardKey.enter) {
                    _createItem();
                  }
                },
child:RaisedButton(focusNode: _createButtonFocusNode,
                 onPressed: () {
                      _createItem();
                    },
                    child: Text("Create"))))

---

还假设存在一个带有_cancelItem事件的取消物料按钮，该按钮应该能够接受焦点上的enter键

您可以复制下面的粘贴运行完整代码
您可以使用

\u node.requestFocus（）

请求焦点，并使用

FocusAttachment

和

attach

在演示代码中，当接收

时，输入
将更改按钮颜色，请参见下面的工作演示

代码片段

_node.requestFocus();
...
FocusAttachment _nodeAttachment;
 _nodeAttachment = _node.attach(context, onKey: _handleKeyPress);
...
 bool _handleKeyPress(FocusNode node, RawKeyEvent event) {
    if (event is RawKeyDownEvent) {
      print('Focus node ${node.debugLabel} got key event: ${event.logicalKey}');
      if (event.logicalKey == LogicalKeyboardKey.enter) {
        print('clicked enter');
        setState(() {
          _color = Colors.deepPurple;
        });
        return true;
      }
    }
    return false;
  }

工作演示


完整代码

// Flutter code sample for FocusNode

// This example shows how a FocusNode should be managed if not using the
// [Focus] or [FocusScope] widgets. See the [Focus] widget for a similar
// example using [Focus] and [FocusScope] widgets.

import 'package:flutter/material.dart';

import 'package:flutter/services.dart';

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

/// This Widget is the main application widget.
class MyApp extends StatelessWidget {
  static const String _title = 'Flutter Code Sample';

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: _title,
      home: Scaffold(
        appBar: AppBar(title: const Text(_title)),
        body: MyStatelessWidget(),
      ),
    );
  }
}

class CustomButton extends StatefulWidget {
  FocusNode focusNode;
  CustomButton({Key key, this.focusNode}) : super(key: key);

  @override
  _CustomButtonState createState() => _CustomButtonState();
}

class _CustomButtonState extends State<CustomButton> {
  bool _focused = false;
  FocusAttachment _nodeAttachment;
  Color _color = Colors.white;

  @override
  void initState() {
    super.initState();
    //widget.focusNode = FocusNode(debugLabel: 'Button');
    widget.focusNode.addListener(_handleFocusChange);
    _nodeAttachment = widget.focusNode.attach(context, onKey: _handleKeyPress);
  }

  void _handleFocusChange() {
    print(widget.focusNode.hasFocus);
    if (widget.focusNode.hasFocus != _focused) {
      setState(() {
        _focused = widget.focusNode.hasFocus;
        _color = Colors.white;
      });
    }
  }

  bool _handleKeyPress(FocusNode node, RawKeyEvent event) {
    if (event is RawKeyDownEvent) {
      print('Focus node ${node.debugLabel} got key event: ${event.logicalKey}');
      if (event.logicalKey == LogicalKeyboardKey.enter) {
        print('clicked enter');
        setState(() {
          _color = Colors.deepPurple;
        });
        return true;
      }
    }
    return false;
  }

  @override
  void dispose() {
    widget.focusNode.removeListener(_handleFocusChange);
    // The attachment will automatically be detached in dispose().
    widget.focusNode.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    _nodeAttachment.reparent();
    return Center(
      child: RaisedButton(
        focusNode: widget.focusNode,
        color: _focused ? _color : Colors.white,
        child: Text(_focused ? "focused" : 'Not focus'),
        onPressed: () {
          print("create item");
        },
      ),
    );
  }
}

class MyStatelessWidget extends StatefulWidget {
  MyStatelessWidget({Key key}) : super(key: key);

  @override
  _MyStatelessWidgetState createState() => _MyStatelessWidgetState();
}

class _MyStatelessWidgetState extends State<MyStatelessWidget> {
  FocusNode _node1 = FocusNode();
  FocusNode _node2 = FocusNode();
  @override
  Widget build(BuildContext context) {
    final TextTheme textTheme = Theme.of(context).textTheme;
    return DefaultTextStyle(
      style: textTheme.headline4,
      child: Column(
        children: [
          CustomButton(
            focusNode: _node1,
          ),
          CustomButton(
            focusNode: _node2,
          ),
          RaisedButton(
              onPressed: () {
                _node1.requestFocus();
                setState(() {});
              },
              child: Text("request focus button 1")),
          RaisedButton(
              onPressed: () {
                _node2.requestFocus();
                setState(() {});
              },
              child: Text("request focus button 2")),
        ],
      ),
    );
  }
}

//FocusNode的颤振代码示例
//此示例显示了如果不使用
//[Focus]或[FocusScope]小部件。请参阅[Focus]小部件以了解类似的信息
//使用[Focus]和[FocusScope]小部件的示例。
进口“包装：颤振/材料.省道”；
导入“包：flifter/services.dart”；
void main（）=>runApp（MyApp（））；
///此小部件是主应用程序小部件。
类MyApp扩展了无状态小部件{
静态常量字符串_title='颤振代码示例'；
@凌驾
小部件构建（构建上下文）{
返回材料PP(
标题：_标题，
家：脚手架(
appBar:appBar（标题：常量文本（_title）），
正文：MyStatelessWidget（），
),
);
}
}
类CustomButton扩展StatefulWidget{
焦点节点；
CustomButton（{Key-Key，this.focusNode}）：super（Key:Key）；
@凌驾
_CustomButtonState createState（）=>\u CustomButtonState（）；
}
类_CustomButtonState扩展状态{
bool_focused=false；
聚焦附件；
颜色_Color=Colors.white；
@凌驾
void initState（）{
super.initState（）；
//widget.focusNode=focusNode（debugLabel:'Button'）；
widget.focusNode.addListener（_handleFocusChange）；
_nodeAttachment=widget.focusNode.attach（上下文，onKey:_handleKeyPress）；
}
void_handleFocusChange（）{
打印（widget.focusNode.hasFocus）；
if（widget.focusNode.hasFocus！=\u聚焦）{
设置状态（）{
_聚焦=widget.focusNode.hasFocus；
_颜色=颜色。白色；
});
}
}
bool\u handleKeyPress（焦点节点，RawKeyEvent事件）{
if（事件为RawKeyDownEvent）{
print（'Focus node${node.debugLabel}已获取密钥事件：${event.logicalKey}'）；
if（event.logicalKey==LogicalKeyboardKey.enter）{
打印（“点击输入”）；
设置状态（）{
_颜色=颜色。深紫色；
});
返回true；
}
}
返回false；
}
@凌驾
无效处置（）{
widget.focusNode.removeListener（_handleFocusChange）；
//附件将在dispose（）中自动分离。
widget.focusNode.dispose（）；
super.dispose（）；
}
@凌驾
小部件构建（构建上下文）{
_nodeAttachment.reparent（）；
返回中心(
孩子：升起按钮(
focusNode:widget.focusNode，
颜色：_聚焦？_颜色：颜色。白色，
子项：文本（_focused？“focused”：“Not focus”），
已按下：（）{
打印（“创建项目”）；
},
),
);
}
}
类MyStatelessWidget扩展了StatefulWidget{
MyStatelessWidget（{Key}）：super（Key:Key）；
@凌驾
_MyStatelessWidgetState createState（）=>MyStatelessWidgetState（）；
}
类_MyStatelessWidgetState扩展状态{
FocusNode_node1=FocusNode（）；
FocusNode_node2=FocusNode（）；
@凌驾
小部件构建（构建上下文）{
final TextTheme TextTheme=Theme.of（context）.TextTheme；
返回DefaultTextStyle(
风格：textTheme.headline4，
子：列(
儿童：[
自定义按钮(
焦点节点：_节点1，
),
自定义按钮(
焦点节点：_节点2，
),
升起的按钮(
已按下：（）{
_node1.requestFocus（）；
setState（（）{}）；
},
子项：文本（“请求焦点按钮1”），
升起的按钮(
已按下：（）{
_node2.requestFocus（）；
setState（（）{}）；
},
子项：文本（“请求焦点按钮2”），
],
),
);
}
}
您可以复制粘贴运行下面的完整代码

您可以使用
\u node.requestFocus（）
请求焦点，并使用
FocusAttachment
和
attach


在演示代码中，当接收
时，输入
将更改按钮颜色，请参见下面的工作演示

代码片段

_node.requestFocus();
...
FocusAttachment _nodeAttachment;
 _nodeAttachment = _node.attach(context, onKey: _handleKeyPress);
...
 bool _handleKeyPress(FocusNode node, RawKeyEvent event) {
    if (event is RawKeyDownEvent) {
      print('Focus node ${node.debugLabel} got key event: ${event.logicalKey}');
      if (event.logicalKey == LogicalKeyboardKey.enter) {
        print('clicked enter');
        setState(() {
          _color = Colors.deepPurple;
        });
        return true;
      }
    }
    return false;
  }

工作演示


完整代码

// Flutter code sample for FocusNode

// This example shows how a FocusNode should be managed if not using the
// [Focus] or [FocusScope] widgets. See the [Focus] widget for a similar
// example using [Focus] and [FocusScope] widgets.

import 'package:flutter/material.dart';

import 'package:flutter/services.dart';

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

/// This Widget is the main application widget.
class MyApp extends StatelessWidget {
  static const String _title = 'Flutter Code Sample';

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: _title,
      home: Scaffold(
        appBar: AppBar(title: const Text(_title)),
        body: MyStatelessWidget(),
      ),
    );
  }
}

class CustomButton extends StatefulWidget {
  FocusNode focusNode;
  CustomButton({Key key, this.focusNode}) : super(key: key);

  @override
  _CustomButtonState createState() => _CustomButtonState();
}

class _CustomButtonState extends State<CustomButton> {
  bool _focused = false;
  FocusAttachment _nodeAttachment;
  Color _color = Colors.white;

  @override
  void initState() {
    super.initState();
    //widget.focusNode = FocusNode(debugLabel: 'Button');
    widget.focusNode.addListener(_handleFocusChange);
    _nodeAttachment = widget.focusNode.attach(context, onKey: _handleKeyPress);
  }

  void _handleFocusChange() {
    print(widget.focusNode.hasFocus);
    if (widget.focusNode.hasFocus != _focused) {
      setState(() {
        _focused = widget.focusNode.hasFocus;
        _color = Colors.white;
      });
    }
  }

  bool _handleKeyPress(FocusNode node, RawKeyEvent event) {
    if (event is RawKeyDownEvent) {
      print('Focus node ${node.debugLabel} got key event: ${event.logicalKey}');
      if (event.logicalKey == LogicalKeyboardKey.enter) {
        print('clicked enter');
        setState(() {
          _color = Colors.deepPurple;
        });
        return true;
      }
    }
    return false;
  }

  @override
  void dispose() {
    widget.focusNode.removeListener(_handleFocusChange);
    // The attachment will automatically be detached in dispose().
    widget.focusNode.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    _nodeAttachment.reparent();
    return Center(
      child: RaisedButton(
        focusNode: widget.focusNode,
        color: _focused ? _color : Colors.white,
        child: Text(_focused ? "focused" : 'Not focus'),
        onPressed: () {
          print("create item");
        },
      ),
    );
  }
}

class MyStatelessWidget extends StatefulWidget {
  MyStatelessWidget({Key key}) : super(key: key);

  @override
  _MyStatelessWidgetState createState() => _MyStatelessWidgetState();
}

class _MyStatelessWidgetState extends State<MyStatelessWidget> {
  FocusNode _node1 = FocusNode();
  FocusNode _node2 = FocusNode();
  @override
  Widget build(BuildContext context) {
    final TextTheme textTheme = Theme.of(context).textTheme;
    return DefaultTextStyle(
      style: textTheme.headline4,
      child: Column(
        children: [
          CustomButton(
            focusNode: _node1,
          ),
          CustomButton(
            focusNode: _node2,
          ),
          RaisedButton(
              onPressed: () {
                _node1.requestFocus();
                setState(() {});
              },
              child: Text("request focus button 1")),
          RaisedButton(
              onPressed: () {
                _node2.requestFocus();
                setState(() {});
              },
              child: Text("request focus button 2")),
        ],
      ),
    );
  }
}

//FocusNode的颤振代码示例
//此示例显示了如果不使用
//[Focus]或[FocusScope]小部件。请参阅[Focus]小部件以了解类似的信息
//使用[Focus]和[FocusScope]小部件的示例。
进口“包装：颤振/材料.省道”；
导入“包：flifter/services.dart”；
void main（）=>runApp（MyApp（））；
///此小部件是主应用程序小部件。
类MyApp扩展了无状态小部件{
静态常量字符串_title='颤振代码示例'；
@凌驾
小部件构建（构建上下文）{
返回材料PP(
标题：_标题，
家：脚手架(
appBar:appBar（标题：常量文本（_title）），
正文：MyStatelessWidget（），
),
);
}
}
类CustomButton扩展StatefulWidget{
焦点节点；
CustomButton（{Key-Key，this.focusNode}）：super（Key:Key）；
@凌驾
_CustomButtonState createState（）=>\u CustomButtonState（）；
}
类_CustomButtonState扩展状态{
bool_focused=false；
聚焦附件；
颜色_Color=Colors.white；
@凌驾
void initState（）{
super.initState（）；
//widget.focusNode=focusNode（debugLabel:'Button'）；
widget.focusNode.addListener（_handleFocusChange）；
_nodeAttachment=widget.focusNode.attach（上下文，onKey:_handleKeyPress）；
}
void_handleFocusChange（）{
打印（widget.focusNode.hasFocus）；
如果（widget.focusNode）。