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

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

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return Center(
        child: Row(
      mainAxisAlignment: MainAxisAlignment.center,
      children: [
        const Text('你好'),
      ],
    ));
  }
}
<<<
import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Row(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [const Text('你好')],
      ),
    );
  }
}