Flutter页面未导航到不同页面

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter 页面导航示例',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: HomePage(),
    );
  }
}

class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('首页'),
      ),
      body: Center(
        child: RaisedButton(
          child: Text('跳转到详情页'),
          onPressed: () {
            Navigator.push(
              context,
              MaterialPageRoute(builder: (context) => DetailPage()),
            );
          },
        ),
      ),
    );
  }
}

class DetailPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('详情页'),
      ),
      body: Center(
        child: RaisedButton(
          child: Text('返回首页'),
          onPressed: () {
            Navigator.pop(context);
          },
        ),
      ),
    );
  }
}