我的解决方案可以在Xcode 5中编译:

#ifdef __IPHONE_8_0
    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");
        }
    }
#endif
    [self.locationManager startUpdatingLocation];

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];

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

为了访问用户在iOS中的位置。您需要添加两个键

NSLocationWhenInUseUsageDescription

NSLocationAlwaysUsageDescription

进入信息。plist文件。

    <key>NSLocationWhenInUseUsageDescription</key>
    <string>Because I want to know where you are!</string>
    <key>NSLocationAlwaysUsageDescription</key>
    <string>Want to know where you are!</string>

请看下图。

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。

要在iOS 8中访问用户位置，你必须添加，

NSLocationAlwaysUsageDescription in the Info.plist 

这将询问用户获取其当前位置的权限。