Flutter 如何创建一个按钮来在Ffltter Webview中转到上一页

通过参考几个网站，我们实现了一项功能，当你在智能手机上的Flutter 网页视图中按下后退按钮时，就会切换到上一页. 然而，当我按下模拟器上的后退按钮时，应用程序关闭，而不转到上一页.如何修改PopSocpe部分中的代码？

密码在这里.

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

final uri = Uri.parse('https://google.com');

class HomeScreen extends StatelessWidget {
  WebViewController controller = WebViewController()
    ..setJavaScriptMode(JavaScriptMode.unrestricted)
    ..setNavigationDelegate(NavigationDelegate(
      onPageFinished: (String url){
        print(url);
      }
    ))
    ..loadRequest(uri);

  HomeScreen({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
   return PopScope(
      canPop: true,
      onPopInvoked : (didPop) async {
          if(await controller.canGoBack()){
            controller.goBack();
          }
        },
    child : Scaffold(
      appBar: AppBar(
        backgroundColor: Colors.orange,
        title: Text('Code Factory'),
        centerTitle: true,
        actions: [
          IconButton(
            onPressed: () {
              controller.loadRequest(uri);
            },

            icon: Icon(
              Icons.home,
            ),
          ),
        ],
      ),
      body: WebViewWidget(
        controller: controller,
        // initialUrl: 'https://google.com',
        // javascriptMode: JavascriptMode.unrestricted,
        // onWebViewCreated: (WebViewController controller) {
        //   this.controller = controller;
        // },
      ),
    ),
    );
  }
}