如何在flutter中验证和更新上一页的数据？

// 上一页
class FirstPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('First Page'),
      ),
      body: Center(
        child: RaisedButton(
          child: Text('Go to Second Page'),
          onPressed: () {
            // 创建要传递的数据
            DataModel data = DataModel();

            // 打开下一页，并传递数据
            Navigator.push(
              context,
              MaterialPageRoute(
                builder: (context) => SecondPage(data: data),
              ),
            ).then((updatedData) {
              // 接收更新后的数据，并更新上一页的数据
              if (updatedData != null) {
                setState(() {
                  data = updatedData;
                });
              }
            });
          },
        ),
      ),
    );
  }
}

// 数据模型类
class DataModel {
  String name;
  int age;

  DataModel({this.name, this.age});
}

// 下一页
class SecondPage extends StatefulWidget {
  final DataModel data;

  SecondPage({this.data});

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

class _SecondPageState extends State<SecondPage> {
  final _formKey = GlobalKey<FormState>();
  TextEditingController _nameController;
  TextEditingController _ageController;

  @override
  void initState() {
    super.initState();
    _nameController = TextEditingController(text: widget.data.name);
    _ageController = TextEditingController(text: widget.data.age.toString());
  }

  @override
  void dispose() {
    _nameController.dispose();
    _ageController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Second Page'),
      ),
      body: Form(
        key: _formKey,
        child: Column(
          children: [
            TextFormField(
              controller: _nameController,
              validator: (value) {
                if (value.isEmpty) {
                  return 'Please enter a name';
                }
                return null;
              },
              decoration: InputDecoration(
                labelText: 'Name',
              ),
            ),
            TextFormField(
              controller: _ageController,
              validator: (value) {
                if (value.isEmpty) {
                  return 'Please enter an age';
                }
                return null;
              },
              decoration: InputDecoration(
                labelText: 'Age',
              ),
            ),
            RaisedButton(
              child: Text('Update Data'),
              onPressed: () {
                if (_formKey.currentState.validate()) {
                  // 数据验证通过，更新数据并返回上一页
                  DataModel updatedData = DataModel(
                    name: _nameController.text,
                    age: int.parse(_ageController.text),
                  );
                  Navigator.pop(context, updatedData);
                }
              },
            ),
          ],
        ),
      ),
    );
  }
}