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。

        // ** Don't forget to add NSLocationWhenInUseUsageDescription in MyApp-Info.plist and give it a string

        self.locationManager = [[CLLocationManager alloc] init];
        self.locationManager.delegate = self;
        // Check for iOS 8. Without this guard the code will crash with "unknown selector" on iOS 7.
        if ([self.locationManager respondsToSelector:@selector(requestWhenInUseAuthorization)]) {
            [self.locationManager requestWhenInUseAuthorization];
        }
        [self.locationManager startUpdatingLocation];


    // Location Manager Delegate Methods    
    - (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
    {
        NSLog(@"%@", [locations lastObject]);

}

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。

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。

在iOS 8中，你需要做两件额外的事情来让定位工作:给你的信息添加一个键。Plist并从位置管理器请求授权，要求它启动

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>

将此添加到代码中

if (IS_OS_8_OR_LATER)
{
    [locationmanager requestWhenInUseAuthorization];

    [locationmanager requestAlwaysAuthorization];
}

添加关键NSLocationWhenInUseUsageDescription或NSLocationAlwaysUsageDescription(后台GPS使用)字符串要求使用GPS在每个信息。Plist从每个目标。 通过运行命令获得许可: (自我initLocationManager: locationManager);

其中“initLocationManager”为:

// asks for GPS authorization on iOS 8
-(void) initLocationManager:(CLLocationManager *) locationManager{

    locationManager = [[CLLocationManager alloc]init];

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

记住，如果键不是在每个信息上。Plist为每个目标，应用程序将不会询问用户。if提供了与iOS 7的兼容性，respondsToSelector:方法保证了未来的兼容性，而不仅仅是解决iOS 7和8的问题。