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。

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];

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];
    }
}

- (void)viewDidLoad
{
    
    [super viewDidLoad];
    self.locationManager = [[CLLocationManager alloc] init];
    
    self.locationManager.delegate = self;
    if([self.locationManager respondsToSelector:@selector(requestAlwaysAuthorization)]){
        NSUInteger code = [CLLocationManager authorizationStatus];
        if (code == kCLAuthorizationStatusNotDetermined && ([self.locationManager respondsToSelector:@selector(requestAlwaysAuthorization)] || [self.locationManager respondsToSelector:@selector(requestWhenInUseAuthorization)])) {
            // choose one request according to your business.
            if([[NSBundle mainBundle] objectForInfoDictionaryKey:@"NSLocationAlwaysUsageDescription"]){
                [self.locationManager requestAlwaysAuthorization];
            } else if([[NSBundle mainBundle] objectForInfoDictionaryKey:@"NSLocationWhenInUseUsageDescription"]) {
                [self.locationManager  requestWhenInUseAuthorization];
            } else {
                NSLog(@"Info.plist does not contain NSLocationAlwaysUsageDescription or NSLocationWhenInUseUsageDescription");
            }
        }
    }
    [self.locationManager startUpdatingLocation];
}

>  #pragma mark - CLLocationManagerDelegate

    - (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 didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
    {
        NSLog(@"didUpdateToLocation: %@", newLocation);
        CLLocation *currentLocation = newLocation;
        
        if (currentLocation != nil) {
            longitudeLabel.text = [NSString stringWithFormat:@"%.8f", currentLocation.coordinate.longitude];
            latitudeLabel.text = [NSString stringWithFormat:@"%.8f", currentLocation.coordinate.latitude];
        }
    }

In iOS 8 you need to do two extra things to get location working: Add a key to your Info.plist and request authorization from the location manager asking it to start. There are two Info.plist keys for the new location authorization. One or both of these keys is required. If neither of the keys are there, you can call startUpdatingLocation but the location manager won’t actually start. It won’t send a failure message to the delegate either (since it never started, it can’t fail). It will also fail if you add one or both of the keys but forget to explicitly request authorization. So the first thing you need to do is to add one or both of the following keys to your Info.plist file:

NSLocationWhenInUseUsageDescription NSLocationAlwaysUsageDescription

这两个键都有一个字符串

这就是为什么你需要位置服务。你可以 输入一个字符串，如“位置是必须找到你在哪里” 和iOS 7一样，可以在InfoPlist中进行本地化。字符串文件。

Swift开发者常犯的一个错误:

首先确保你添加了一个值到plist为NSLocationWhenInUseUsageDescription或NSLocationAlwaysUsageDescription。

如果你仍然没有看到一个窗口弹出要求授权，看看你是否把行var locationManager = CLLocationManager()在你的视图控制器的viewDidLoad方法。如果这样做，那么即使调用locationManager.requestWhenInUseAuthorization()，也不会显示任何内容。这是因为在viewDidLoad执行后，locationManager变量被释放(清除)。

解决方案是在类方法的顶部找到var locationManager = CLLocationManager()行。

我也因为同样的问题而抓狂。Xcode给出错误:

试图启动MapKit位置更新而没有提示 位置授权。必须调用-[CLLocationManager requestWhenInUseAuthorization]或-[CLLocationManager . request requestAlwaysAuthorization]。

但即使实现了上述方法之一，它也不会提示用户，除非信息中有条目。NSLocationAlwaysUsageDescription或NSLocationWhenInUseUsageDescription。

添加以下行到您的信息。Plist，其中字符串值代表您需要访问用户位置的原因

<key>NSLocationWhenInUseUsageDescription</key>
<string>This application requires location services to work</string>

<key>NSLocationAlwaysUsageDescription</key>
<string>This application requires location services to work</string>

我认为自从我在Xcode 5中开始这个项目以来，这些条目可能已经丢失了。我猜Xcode 6可能会为这些键添加默认条目，但还没有确认。

你可以在这里找到更多关于这两个设置的信息