将TextFormField中的数据从另一个小部件检索到main

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

class _MyAppState extends State<MyApp> {
  String retrievedData = '';

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Retrieve Data Example'),
        ),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              Text('Retrieved Data: $retrievedData'),
              AnotherWidget(callback: (data) {
                setState(() {
                  retrievedData = data;
                });
              }),
            ],
          ),
        ),
      ),
    );
  }
}

class AnotherWidget extends StatelessWidget {
  final Function(String) callback;

  AnotherWidget({required this.callback});

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: EdgeInsets.all(16.0),
      child: TextFormField(
        onChanged: (value) {
          callback(value);
        },
        decoration: InputDecoration(
          labelText: 'Enter data',
        ),
      ),
    );
  }
}

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