我尽了最大的努力来编写最小的代码。我认为最好将UI和服务分开。现在，它看起来更干净，更漂亮。
您可能会注意到，我为您在服务中编写了额外的几行代码。在checkLocationPermission（）中，我尝试处理所有可能的结果。在getCurrentLocation（）中，我试图增强和调整。
在UI的一部分，你可以看到我是如何管理加载的。我自己改进代码。现在，它完美地工作。
main.dart

import "package:flutter/material.dart";
import "package:myapp/location_service.dart";
void main() {
  WidgetsFlutterBinding.ensureInitialized();
  runApp(const MyApp());
}
class MyApp extends StatelessWidget {
  const MyApp({super.key});
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: "Flutter Demo",
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      home: const TestScreen(),
      debugShowCheckedModeBanner: false,
    );
  }
}
class TestScreen extends StatefulWidget {
  const TestScreen({super.key});
  @override
  State<TestScreen> createState() => _TestScreenState();
}
class _TestScreenState extends State<TestScreen> {
  LocationService instance = LocationService.instance;
  bool isLoading = false;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text("Location Tracking"),
      ),
      body: Center(
        child: isLoading
            ? const CircularProgressIndicator()
            : Column(
                mainAxisAlignment: MainAxisAlignment.center,
                crossAxisAlignment: CrossAxisAlignment.start,
                children: <Widget>[
                  Text(
                    instance.isLocationPermissionGranted
                        ? "Location Permission: Granted"
                        : "Location Permission: Denied",
                  ),
                  const SizedBox(height: 20),
                  Text("Latitude: ${instance.currentPosition.latitude}"),
                  const SizedBox(height: 20),
                  Text("Longitude: ${instance.currentPosition.longitude}"),
                  const SizedBox(height: 20),
                  ElevatedButton(
                    onPressed: isLoading
                        ? null
                        : () async {
                            isLoading = true;
                            setState(() {});
                            await instance.checkLocationPermission();
                            isLoading = false;
                            setState(() {});
                          },
                    child: const Text("Request Location Permission"),
                  ),
                ],
              ),
      ),
    );
  }
}

location_service.dart

import "dart:async";
import "dart:developer";
import "package:geolocator/geolocator.dart";
class LocationService {
  LocationService._();
  static final LocationService instance = LocationService._();
  bool isLocationPermissionGranted = false;
  Position currentPosition = const Position(
    longitude: 0.0,
    latitude: 0.0,
    timestamp: null,
    accuracy: 0.0,
    altitude: 0.0,
    heading: 0.0,
    speed: 0.0,
    speedAccuracy: 0.0,
    floor: 0,
    isMocked: true,
  );
  Future<void> checkLocationPermission() async {
    final LocationPermission permission = await Geolocator.requestPermission();
    switch (permission) {
      case LocationPermission.denied:
        break;
      case LocationPermission.deniedForever:
        break;
      case LocationPermission.whileInUse:
        isLocationPermissionGranted = true;
        await getCurrentLocation();
        break;
      case LocationPermission.always:
        isLocationPermissionGranted = true;
        await getCurrentLocation();
        break;
      case LocationPermission.unableToDetermine:
        break;
    }
    return Future<void>.value();
  }
  Future<void> getCurrentLocation() async {
    try {
      currentPosition = await Geolocator.getCurrentPosition();
      log("LocationService : Success : ${currentPosition.toJson()}");
    } on TimeoutException catch (e) {
      log("LocationService : Failure : ${e.message}");
    }
    return Future<void>.value();
  }
}