向后兼容解决方案:

SEL requestSelector = NSSelectorFromString(@"requestWhenInUseAuthorization");
if ([CLLocationManager authorizationStatus] == kCLAuthorizationStatusNotDetermined &&
    [self.locationManager respondsToSelector:requestSelector]) {
    [self.locationManager performSelector:requestSelector withObject:NULL];
} else {
    [self.locationManager startUpdatingLocation];
}

在Info.plist中设置NSLocationWhenInUseUsageDescription键

解决方案与向后兼容，不产生Xcode警告:

SEL requestSelector = NSSelectorFromString(@"requestWhenInUseAuthorization");
if ([CLLocationManager authorizationStatus] == kCLAuthorizationStatusNotDetermined &&
  [self.locationManager respondsToSelector:requestSelector]) {
((void (*)(id, SEL))[self.locationManager methodForSelector:requestSelector])(self.locationManager, requestSelector);
  [self.locationManager startUpdatingLocation];
} else {
  [self.locationManager startUpdatingLocation];
}

在Info.plist中设置NSLocationWhenInUseUsageDescription键。

对于iOS版本11.0+: 在Info.plist中设置NSLocationAlwaysAndWhenInUseUsageDescription键。还有另外2把钥匙。

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

}

在[locationManager startUpdatingLocation];之前，添加一个iOS8位置服务请求:

if([locationManager respondsToSelector:@selector(requestAlwaysAuthorization)])
    [locationManager requestAlwaysAuthorization];

编辑应用程序的信息。并添加键NSLocationAlwaysUsageDescription与字符串值，将显示给用户(例如，我们尽我们最大的努力来保持您的电池寿命。)

如果你的应用程序只在应用程序打开时需要位置服务，请替换:

requestAlwaysAuthorization with requestWhenInUseAuthorization和

NSLocationAlwaysUsageDescription和NSLocationWhenInUseUsageDescription。

这是ios 8的问题 将此添加到代码中

if (IS_OS_8_OR_LATER)
{
    [locationmanager requestWhenInUseAuthorization];

    [locationmanager requestAlwaysAuthorization];
}

到info.plist:

 <key>NSLocationUsageDescription</key>
 <string>I need location</string>
 <key>NSLocationAlwaysUsageDescription</key>
 <string>I need location</string>
 <key>NSLocationWhenInUseUsageDescription</key>
 <string>I need location</string>

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];