Flutter创建自定义的软键盘

在Flutter中创建自定义软键盘可以通过RawKeyboardListener和RawKeyEvent来实现。以下是一个简单的自定义软键盘的例子：

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
 
void main() {
  runApp(MyApp());
}
 
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: CustomKeyboard(),
    );
  }
}
 
class CustomKeyboard extends StatefulWidget {
  @override
  _CustomKeyboardState createState() => _CustomKeyboardState();
}
 
class _CustomKeyboardState extends State<CustomKeyboard> {
  final FocusNode _focusNode = FocusNode();
  String _input = '';
 
  @override
  void dispose() {
    _focusNode.dispose();
    super.dispose();
  }
 
  void _handleKeyEvent(RawKeyEvent event) {
    if (event is RawKeyDownEvent) {
      if (event.physicalKey == PhysicalKeyboardKey.keyA) {
        _input += 'A';
      } else if (event.physicalKey == PhysicalKeyboardKey.keyB) {
        _input += 'B';
      }
      // 处理其他按键...
      setState(() {});
    }
  }
 
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: RawKeyboardListener(
        focusNode: _focusNode,
        onKey: _handleKeyEvent,
        child: Center(
          child: Text(_input),
        ),
      ),
    );
  }
}

这个例子中，我们创建了一个自定义的CustomKeyboard，它使用RawKeyboardListener来监听键盘事件。当特定按键被按下时，例如按下"A"或"B"键，程序会更新文本输入。这个例子展示了如何捕获物理按键事件，并根据需要进行处理。