整体思路：
获取定位需要用到的是CoreLocation.framework里面的CLLocationManager类，设置了详细的参数和代理后，获取成功和失败的信息都会在代理方法里面体现。
详细步骤：

1.在系统定位权限打开的情况下再进行操作

    if ([CLLocationManager locationServicesEnabled]) {
        locationmanager = [[CLLocationManager alloc]init];
        locationmanager.delegate = self;
        [locationmanager requestAlwaysAuthorization];
        currentCity = [NSString new];
        [locationmanager requestWhenInUseAuthorization];
        
        //设置精度
        locationmanager.desiredAccuracy = kCLLocationAccuracyBest;
        locationmanager.distanceFilter = 5.0;
        [locationmanager startUpdatingLocation];
    }

2.获取定位成功后调用的代理方法

-(void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray<CLLocation *> *)locations
{
    [locationmanager stopUpdatingHeading];
    //旧址
    CLLocation *currentLocation = [locations lastObject];
    CLGeocoder *geoCoder = [[CLGeocoder alloc]init];
    //打印当前的经度与纬度
    NSLog(@"%f,%f",currentLocation.coordinate.latitude,currentLocation.coordinate.longitude);
    
    //上传经纬度到服务器
    
    //获取国家城市信息
    [geoCoder reverseGeocodeLocation:currentLocation completionHandler:^(NSArray<CLPlacemark *> * _Nullable placemarks, NSError * _Nullable error) {
        if (placemarks.count > 0) {
            CLPlacemark *placeMark = placemarks[0];
            currentCity = placeMark.locality;
            if (!currentCity) {
                currentCity = @"获取城市失败";
            }
            NSLog(@"%@",currentCity);
            NSLog(@"%@",placeMark.country);//国家
            
        }
    }];
    
}

3.获取定位失败后调用的代理方法

-(void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error{
    //去设置中心打开定位服务
    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:UIApplicationOpenSettingsURLString]];
}