iOS 9在使用定位服务获取经纬度的时候，系统不调用代理方法，请问如何解决？

@interface NearbyViewController (){
 // CLLocationManager *_locationManager;
 CLGeocoder *_lgeocoder;
 }
 @property (strong, nonatomic) CLLocationManager *locationManager;

@end

(void)viewDidLoad {
 [super viewDidLoad];
 // Do any additional setup after loading the view.
 _locationManager = [[CLLocationManager alloc]init];
 _locationManager.delegate = self;
 // _locationManager.desiredAccuracy = kCLLocationAccuracyBest;
 // _locationManager.distanceFilter = 1000.0f;
 [_locationManager startUpdatingLocation];
 }


(void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations{
 NSLog(@"%@",locations);
 // CLLocation *location = [locations objectAtIndex:0];
 // [self request_NearbyWithWeidu:[NSString stringWithFormat:@"%f",location.coordinate.longitude] Jindu:[NSString stringWithFormat:@"%f",location.coordinate.latitude]];
 // NSLog(@"%f",location.coordinate.longitude);
 // NSLog(@"%f",location.coordinate.latitude);
 [_locationManager stopUpdatingLocation];
 }


(void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error{
 NSLog(@"%@",error);
 }