import 'dart:developer';

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

void main() {
  runApp(
    MaterialApp(
      title: 'Flutter Demo',
      home: const MyHomePage(title: 'Flutter Demo KeyboardListener'),
    ),
  );
}

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

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

class _MyHomePageState extends State<MyHomePage> {
  final FocusNode focusNode = FocusNode();
  String _text = '';

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text(widget.title)),
      body: Column(
        children: [
          /// Text
          Text(_text),

          /// Change KeyBoard Language.
          SizedBox(width: 30, child: TextField()),

          /// Event Listener
          KeyboardListener(
            autofocus: true,
            focusNode: focusNode,
            onKeyEvent: (event) {
              if (event.runtimeType == KeyDownEvent) {
                log('event character: ${event.character}');
                setState(() {
                  if (event.character != null) {
                    _text += event.character!;
                  }
                });
              }
            },
            child: ElevatedButton(
              onPressed: () {
                focusNode.requestFocus();
                setState(() {
                  _text = '';
                });
              },
              child: Text('clear & focus'),
            ),
          ),
        ],
      ),
    );
  }
}