如何在 Flutter 中实现地理定位和地图功能？

在Flutter中实现地理定位和地图功能，你可以使用location插件来获取当前位置，以及google_maps_flutter插件来在应用中展示Google Maps。

首先，在pubspec.yaml中添加依赖：

dependencies:
  flutter:
    sdk: flutter
  location: ^4.3.0
  google_maps_flutter: ^2.0.1

然后，获取地理定位权限并使用location插件获取当前位置：

import 'package:location/location.dart';
 
Location location = Location();
 
var locationData = await location.getLocation();
double latitude = locationData.latitude;
double longitude = locationData.longitude;

接下来，在地图上显示当前位置，可以使用google_maps_flutter插件：

import 'package:google_maps_flutter/google_maps_flutter.dart';
 
GoogleMapController mapController;
 
final GoogleMap googleMap = GoogleMap(
  initialCameraPosition: CameraPosition(
    target: LatLng(latitude, longitude),
    zoom: 15.0,
  ),
  onMapCreated: (controller) {
    mapController = controller;
  },
);

完整的示例代码：

import 'package:flutter/material.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:location/location.dart';
 
void main() => runApp(MyApp());
 
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: MapsSample(),
    );
  }
}
 
class MapsSample extends StatefulWidget {
  @override
  State<MapsSample> createState() => MapsSampleState();
}
 
class MapsSampleState extends State<MapsSample> {
  Location location = Location();
  GoogleMapController mapController;
 
  var locationData;
  double latitude;
  double longitude;
 
  @override
  void initState() {
    super.initState();
    getLocationData();
  }
 
  getLocationData() async {
    locationData = await location.getLocation();
    latitude = locationData.latitude;
    longitude = locationData.longitude;
    setState(() {});
  }
 
  @override
  Widget build(BuildContext context) {
    if (latitude == null || longitude == null) {
      return Scaffold(
        body: Center(
          child: Text('Loading...'),
        ),
      );
    }
    return Scaffold(
      body: GoogleMap(
        initialCameraPosition: CameraPosition(
          target: LatLng(latitude, longitude),
          zoom: 15.0,
        ),
        onMapCreated: (controller) {
          mapController = controller;
        },
      ),
    );
  }
}

确保你有正确的Google Maps API密钥，并在AndroidManifest.xml和Info.plist中配置好。在实际应用中，你可能还需要处理权限请求和其他错误情况。