Flutter:如何在另一个页面正在加载时显示正在加载的页面

import 'package:flutter/material.dart';

class LoadingPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: CircularProgressIndicator(), // 显示一个加载指示器
      ),
    );
  }
}

class HomePage extends StatelessWidget {
  void fetchData() async {
    Navigator.push(
      context,
      MaterialPageRoute(builder: (context) => LoadingPage()),
    );

    // 模拟数据加载过程
    await Future.delayed(Duration(seconds: 2));

    Navigator.pop(context); // 返回到HomePage
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Home'),
      ),
      body: Center(
        child: RaisedButton(
          child: Text('Fetch Data'),
          onPressed: fetchData,
        ),
      ),
    );
  }
}