iphone - 试图在后台获取位置更新不起作用

Question

大家好，当我的应用程序处于后台时，我正在尝试获取位置更新。但是下面的代码似乎不起作用。IF 语句永远不正确。我还在 info.plist 文件中设置了必要的键。我在 iphone 3GS 和 ipad 3 中运行代码。

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    

    // Override point for customizatio-n after application launch.
    id locationValue = [launchOptions objectForKey:UIApplicationLaunchOptionsLocationKey];
    if (locationValue)
    {
        // create a new manager and start checking for sig changes

        locManager = [[CLLocationManager alloc] init];

        locManager.delegate = self;

        [locManager startMonitoringSignificantLocationChanges];

        return YES;
    }