如何使用Webview_flutter包显示国家/地区的地图？

Question

在研究中，我确实想使用html代码显示地图。问题在于地图不显示，而只是显示地图的html代码。请帮我。这是下面的代码：

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

class HomeScreen extends StatefulWidget {
  @override
  _HomeScreenState createState() => _HomeScreenState();
}



class _HomeScreenState extends State<HomeScreen> {
  WebViewController _controller;
  String _inital = "Carte de la françe";

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text("$_inital"),
          centerTitle: true,
        ),
        body: 
        WebView(
          onWebViewCreated: (WebViewController webViewController) {
            _controller = webViewController;
            _loadHtmlFromAssets();
          },
          initialUrl: 'assets/pages/samplepage.html',
          
          javascriptMode: JavascriptMode.unrestricted,
          
        ));
  }

 _loadHtmlFromAssets() async {
    String fileText =
        await rootBundle.loadString('assets/pages/samplepage.html');
    _controller.loadUrl(Uri.dataFromString(fileText,
            mimeType: 'text/javascript',base64: true,  encoding: Encoding.getByName('utf-8'), )
        .toString());
  } 
}