我最终解决了自己的问题。

显然，在iOS 8 SDK中，在开始位置更新之前需要调用CLLocationManager上的requestAlwaysAuthorization(用于后台位置)或requestWhenInUseAuthorization(仅用于前台位置)。

在Info中还需要NSLocationAlwaysUsageDescription或NSLocationWhenInUseUsageDescription键。Plist并在提示符中显示一条消息。加上这些就解决了我的问题。

更多详细信息，请查看:Core-Location-Manager-Changes-in-ios-8

objective - c程序 遵循以下指示:

对于iOS-11 对于iOS 11，看看这个答案:iOS 11位置访问

需要在plist中添加两个键并提供如下图所示的消息:

 1. NSLocationAlwaysAndWhenInUseUsageDescription 
 2. NSLocationWhenInUseUsageDescription
 3. NSLocationAlwaysUsageDescription

对于iOS-10及以下版本:

NSLocationWhenInUseUsageDescription

locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;
locationManager.desiredAccuracy = kCLLocationAccuracyThreeKilometers;
if([locationManager respondsToSelector:@selector(requestWhenInUseAuthorization)]){
    [locationManager requestWhenInUseAuthorization];
}else{
    [locationManager startUpdatingLocation];
} 

委托方法

#pragma mark - Lolcation Update 
- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error
{
    NSLog(@"didFailWithError: %@", error);
    UIAlertView *errorAlert = [[UIAlertView alloc]
                               initWithTitle:@"Error" message:@"Failed to Get Your Location" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
    [errorAlert show];
}
-(void)locationManager:(CLLocationManager *)manager didChangeAuthorizationStatus:(CLAuthorizationStatus)status
{
    switch (status) {
        case kCLAuthorizationStatusNotDetermined:
        case kCLAuthorizationStatusRestricted:
        case kCLAuthorizationStatusDenied:
        {
            // do some error handling
        }
            break;
        default:{
            [locationManager startUpdatingLocation];
        }
            break;
    }
}
- (void)locationManager:(CLLocationManager *)manager
     didUpdateLocations:(NSArray *)locations
{
    CLLocation *location = [locations lastObject];
    userLatitude =  [NSString stringWithFormat:@"%f", location.coordinate.latitude] ;
    userLongitude =  [NSString stringWithFormat:@"%f",location.coordinate.longitude];
    [locationManager stopUpdatingLocation];
}

迅速的过程

遵循以下指示:

对于iOS-11 对于iOS 11，看看这个答案:iOS 11位置访问

需要在plist中添加两个键并提供如下图所示的消息:

 1. NSLocationAlwaysAndWhenInUseUsageDescription 
 2. NSLocationWhenInUseUsageDescription
 3. NSLocationAlwaysUsageDescription

对于iOS-10及以下版本:

import CoreLocation
class ViewController: UIViewController ,CLLocationManagerDelegate {
var locationManager = CLLocationManager()

//MARK- Update Location 
func updateMyLocation(){
    locationManager.delegate = self;
    locationManager.desiredAccuracy = kCLLocationAccuracyThreeKilometers;
    if locationManager.respondsToSelector(#selector(CLLocationManager.requestWhenInUseAuthorization)){
       locationManager.requestWhenInUseAuthorization()
    }
    else{
        locationManager.startUpdatingLocation()
    }
}

委托方法

//MARK: Location Update
func locationManager(manager: CLLocationManager, didFailWithError error: NSError) {
    NSLog("Error to update location :%@",error)
}
func locationManager(manager: CLLocationManager, didChangeAuthorizationStatus status: CLAuthorizationStatus) {
    switch status {
    case .NotDetermined: break
    case .Restricted: break
    case .Denied:
            NSLog("do some error handling")
        break
    default:
        locationManager.startUpdatingLocation()
    }
}
func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
     let location = locations.last! as CLLocation
    var latitude = location.coordinate.latitude
    var longitude = location.coordinate.longitude

}

苹果的文件显示:

https://developer.apple.com/documentation/corelocation/requesting_permission_to_use_location_services https://developer.apple.com/documentation/corelocation/cllocationmanager/1620562-requestwheninuseauthorization

As of iOS 8, the presence of a NSLocationWhenInUseUsageDescription or a NSLocationAlwaysUsageDescription key value in your app's Info.plist file is required. It's then also necessary to request permission from the user prior to registering for location updates, either by calling [self.myLocationManager requestWhenInUseAuthorization] or [self.myLocationManager requestAlwaysAuthorization] depending on your need. The string you entered into the Info.plist will then be displayed in the ensuing dialog.

如果用户授予了权限，则业务照常进行。如果他们拒绝权限，则委托不会被告知位置更新。

对于那些使用Xamarin，我必须添加关键NSLocationWhenInUseUsageDescription的信息。手动plist，因为在Xamarin 5.5.3 Build 6或XCode 6.1的下拉列表中都不可用-只有NSLocationUsageDescription在列表中，这导致CLLocationManager继续无声地失败。

用于询问位置的旧代码将无法在iOS 8中使用。您可以尝试使用此方法进行位置授权:

- (void)requestAlwaysAuthorization
{
    CLAuthorizationStatus status = [CLLocationManager authorizationStatus];

    // If the status is denied or only granted for when in use, display an alert
    if (status == kCLAuthorizationStatusAuthorizedWhenInUse || status ==        kCLAuthorizationStatusDenied) {
        NSString *title;
        title = (status == kCLAuthorizationStatusDenied) ? @"Location services are off" :   @"Background location is not enabled";
        NSString *message = @"To use background location you must turn on 'Always' in the Location Services Settings";

        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:title
                                                            message:message
                                                           delegate:self
                                                  cancelButtonTitle:@"Cancel"
                                                  otherButtonTitles:@"Settings", nil];
        [alertView show];
    }
    // The user has not enabled any location services. Request background authorization.
    else if (status == kCLAuthorizationStatusNotDetermined) {
        [self.locationManager requestAlwaysAuthorization];
    }
}

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
    if (buttonIndex == 1) {
        // Send the user to the Settings for this app
        NSURL *settingsURL = [NSURL URLWithString:UIApplicationOpenSettingsURLString];
        [[UIApplication sharedApplication] openURL:settingsURL];
    }
}

为了确保这与iOS 7向后兼容，你应该检查用户运行的是iOS 8还是iOS 7。例如:

#define IS_OS_8_OR_LATER ([[[UIDevice currentDevice] systemVersion] floatValue] >= 8.0)

//In ViewDidLoad
if(IS_OS_8_OR_LATER) {
   [self.locationManager requestAlwaysAuthorization];
}

[self.locationManager startUpdatingLocation];