使用Flutter时未显示MapBox地图

Question

我正处于尝试在最近创建的Flutter应用中显示地图的开始阶段。问题是，我只得到一个空白屏幕，而不是使用MapBox.com上的内置Studio工具创建的地图。

我尝试为我正在工作的项目在iOS文件夹中修改'Info.plist'，

class _HomePageState extends State<HomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: new AppBar(
        centerTitle: true,
        title: new Text("Orlando"),
        actions: <Widget>[
          IconButton(
              icon: Icon(FontAwesomeIcons.mapMarkerAlt), onPressed: () {}),
        ],
      ),
      body: new FlutterMap(
        options: new MapOptions(
          center: new LatLng(51.5, -0.09),
          zoom: 13.0,
        ),
        layers: [
          new TileLayerOptions(
            urlTemplate:
                "mapbox://styles/carlosblancorocks/cjzk2tc9i5hqd1cpi5oz5gg5y",
            additionalOptions: {
              'accessToken':
                  'pk.eyJ1IjoiY2FybG9zYmxhbmNvcm9ja3MiLCJhIjoiY2p6azhsYmFkMDAyYTNncWlwZXo4ZWJ1cyJ9.ZD6ww-uwtXAM13ZCgRTqZw',
              'id': 'mapbox.mapbox-streets-v8',
            },
          ),
          new MarkerLayerOptions(
            markers: [
              new Marker(
                width: 80.0,
                height: 80.0,
                point: new LatLng(51.5, -0.09),
                builder: (ctx) => new Container(
                      child: IconButton(
                        icon: Icon(Icons.location_on),
                        color: Colors.red,
                        iconSize: 45.0,
                        onPressed: () {
                          print('yeahaa');
                        },
                      ),
                    ),
              ),
            ],
          ),
        ],
      ),
    );
  }
}

我知道：https://i.imgur.com/35JvCUY.png