didUpdateLocations 方法从未被调用

我正在 iphone sdk4.0 上制作一个应用程序。其中更新位置方法从未被调用。 我在下面给出了我的代码。请帮忙。提前致谢。

-(id)init
{
    [super init];

    obj=[[UIApplication sharedApplication]delegate];

    locationManager = [[CLLocationManager alloc] init];
    locationManager.delegate = self;
    //locationManager.distanceFilter = kCLDistanceFilterNone; // whenever we move
    locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters; // 100 m
    [locationManager startUpdatingLocation];

    return self;

}

-(void)locationManager:(CLLocationManager *)manager
   didUpdateToLocation:(CLLocation *)newLocation
          fromLocation:(CLLocation *)oldLocation
{
    NSLog(@"%f",newLocation.coordinate.latitude);

    NSLog(@"%f",newLocation.coordinate.longitude);

    obj=[[UIApplication sharedApplication]delegate];

    location=[[CLLocation alloc]initWithLatitude:newLocation.coordinate.latitude longitude:newLocation.coordinate.longitude];
    obj.lattitude1=[NSString stringWithFormat:@"%f",newLocation.coordinate.latitude];

    obj.longitude1=[NSString stringWithFormat:@"%f",newLocation.coordinate.longitude];
    //location=[[CLLocation alloc]initWithLatitude:39.9883 longitude:-75.262227];
}

此外，在 iOS8 中你必须有两个额外的东西：

• 将密钥添加到您的 Info.plist 并向位置管理器请求授权，要求其启动。

  • NSLocationWhenInUseUsageDescription

  • NSLocationAlwaysUsageDescription

• 您需要为相应的定位方法请求授权。

  • [self.locationManager requestWhenInUseAuthorization]

  • [self.locationManager requestAlwaysAuthorization]

代码示例：

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];

Source: http://nevan.net/2014/09/core-location-manager-changes-in-ios-8/ http://nevan.net/2014/09/core-location-manager-changes-in-ios-8/