Flutter - flutter_map和flutter_map_marker_popup，弹出窗口不显示

问：

我正在我的 Flutter 应用程序中处理地图页面，地图和标记位于指定位置，但是当我单击标记时，它没有显示我在代码中设置的任何弹出消息。请帮忙。 flutter_map：^0.13.0 flutter_map_marker_popup：^2.0.2 网址：^0.13.2

And here is my code:
import 'package:flutter/material.dart';
import 'package:gomobile/components/customAppBar.dart';
import 'package:gomobile/components/customDrawer.dart';
import 'package:flutter_map/flutter_map.dart';
import 'package:flutter_map_marker_popup/flutter_map_marker_popup.dart';
import 'package:latlong2/latlong.dart';

class ApplicationStatisticPage extends StatelessWidget {
const ApplicationStatisticPage({Key? key}) : super(key: key);

@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Application Statistics'),
),
body: const FlutterMapWidget(),
);
}
}

class FlutterMapWidget extends StatefulWidget {
const FlutterMapWidget({Key? key}) : super(key: key);

@override
_FlutterMapWidgetState createState() => _FlutterMapWidgetState();
}

class _FlutterMapWidgetState extends State<FlutterMapWidget> {
final PopupController _popupLayerController = PopupController();

@override
Widget build(BuildContext context) {
final LatLng markerLocation = LatLng(3.1341, 101.7153);

return FlutterMap(
  options: MapOptions(
    center: markerLocation,
    zoom: 15.0,
  ),
  layers: [
    TileLayerOptions(
      urlTemplate: 'https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png',
      subdomains: ['a', 'b', 'c'],
    ),
    PopupMarkerLayerOptions(
      popupSnap: PopupSnap.markerCenter,
      markers: [
        Marker(
          width: 80.0,
          height: 80.0,
          point: markerLocation,
          builder: (ctx) => const Icon(
            Icons.location_on,
            size: 80.0,
            color: Colors.red,
          ),
        ),
      ],
      popupBuilder: (BuildContext context, Marker marker) {
        return const Card(
          child: ListTile(
            title: Text('MYTOWN'),
            subtitle: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text('1. HP Loan Application'),
                Text('WAN AMRAN BIN WAN HUSSIN(790415-12-5XXX)'),
              ],
            ),
          ),
        );
      },
      popupController: _popupLayerController,
    ),
  ],
  mapController: MapController(),
);

} }