#import <CoreLocation/CoreLocation.h>

.h

@property (nonatomic,strong) CLLocationManager * manager;

@property (nonatomic,assign) BOOL isLocationed;

.m

-(CLLocationManager *)manager{
    if (!_manager) {
        _manager = [[CLLocationManager alloc]init];
        _manager.delegate = self;
        _manager.desiredAccuracy = kCLLocationAccuracyBest;
    }
    return _manager;
}

#pragma mark
#pragma mark - 判断手机是否开启定位功能 然后开始定位
- (void)findLocationCity{
    
    if ([CLLocationManager locationServicesEnabled]) {
        if ([self.manager respondsToSelector:@selector(requestWhenInUseAuthorization)]) {
//            NSLog(@"requestWhenInUseAuthorization");
            [self.manager requestWhenInUseAuthorization];
        }
        [self.manager startUpdatingLocation];
//        NSLog(@"start GPS");
    }else{
        NSLog(@"提醒用户：定位服务未开启，可在设置中进行修改....");
    }
    
}

#pragma mark
#pragma mark - 获取 GPS 经度和纬度
- (void)locationManager:(CLLocationManager *)manager
     didUpdateLocations:(NSArray<CLLocation *> *)locations{
    
    if (!_isLocationed) {
        
        CLLocation * location1 = [locations lastObject];
        CLLocationCoordinate2D coordinate = location1.coordinate;
        CLGeocoder * geocoder = [[CLGeocoder alloc]init];
        CLLocation * location = [[CLLocation alloc]initWithLatitude:coordinate.latitude longitude:coordinate.longitude];
        [geocoder reverseGeocodeLocation:location completionHandler:^(NSArray<CLPlacemark *> * _Nullable placemarks, NSError * _Nullable error) {
            if (placemarks.count > 0) {
                CLPlacemark * placemark = [placemarks objectAtIndex:0];
                
                NSString * city = placemark.locality;
                
                if (!city) {
                    city = placemark.administrativeArea;
                }
                    
                    UIAlertController * ac = [UIAlertController alertControllerWithTitle:@"切换当前城市:" message:city preferredStyle:UIAlertControllerStyleAlert];
                    
                    UIAlertAction * aa = [UIAlertAction actionWithTitle:@"确认" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
                        
                           [WeatherView_Model weatherWithCurrentCity:city finishBlock:^(WeatherView_Model *weatherModel) {
                            self.weather_View.weatherModel = weatherModel;
                        } errorBlock:^{
                        }];
                    }];
                    [ac addAction:aa];
                    
                    UIAlertAction * aa2 = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil];
                    [ac addAction:aa2];
                    
                    [self presentViewController:ac animated:YES completion:nil];
        
            }else if (error == nil && placemarks.count == 0){
                NSLog(@"No results were returned.");
            }else if (error != nil){
                NSLog(@"An error occurred = %@", error);
            }
        }];
        
        self.isLocationed = YES;
    }
    [self.manager stopUpdatingLocation];
}

#pragma mark
#pragma mark - 定位失败返回
- (void)locationManager:(CLLocationManager *)manager
       didFailWithError:(NSError *)error{
    if (error.code == kCLErrorDenied) {
        NSLog(@"Error : %@",error);
    }
}

仅供学习 参考