如何从子Widget更新父Widget的状态，同时在Flutter中更新子Widget的状态？

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  String _parentText = 'Parent Widget';

  void _updateParentText(String newText) {
    setState(() {
      _parentText = newText;
    });
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Flutter State Management'),
        ),
        body: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text(_parentText),
            SizedBox(height: 20),
            ChildWidget(callback: _updateParentText),
          ],
        ),
      ),
    );
  }
}

class ChildWidget extends StatefulWidget {
  final Function(String) callback;

  const ChildWidget({Key? key, required this.callback}) : super(key: key);

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

class _ChildWidgetState extends State<ChildWidget> {
  String _childText = 'Child Widget';

  void _updateChildText(String newText) {
    setState(() {
      _childText = newText;
    });
    widget.callback(_childText);
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        Text(_childText),
        ElevatedButton(
          onPressed: () => _updateChildText('Updated Child Widget'),
          child: Text('Update Child'),
        ),
      ],
    );
  }
}