因为有个项目需要获取光的值，在不同光线下值得获取，在查阅了些资料之后发现：

pragma mark - 磁场数据

• (void)locationManager:(CLLocationManager )manager didUpdateHeading:(CLHeading )newHeading {
  // 0 标示北方
  NSLog(@”heading:%f”,newHeading.magneticHeading);
  }

-(void)locationManager:(CLLocationManager )manager rangingBeaconsDidFailForRegion:(CLBeaconRegion )region withError:(NSError *)error
{

NSLog(@"heading:%@",region);

}

• (void)viewWillDisappear:(BOOL)animated {
  [super viewWillDisappear:animated];

  [self stopAccelerometer];
  [self stopGyro];
  [self stopProcimity];
  [self stopLevel];
  [self stopLocation];

}

当程序再次启动的时候需要结束

• (void)stopAccelerometer {
  if (_cmmanger.isAccelerometerActive) {
  [_cmmanger stopAccelerometerUpdates];
  }

}
- (void)stopGyro {

if(_cmmanger.isGyroActive){
    [_cmmanger stopGyroUpdates];
}

}

• (void)stopProcimity{
  [[NSNotificationCenter defaultCenter] removeObserver:self name:UIDeviceProximityStateDidChangeNotification object:nil];
  }

• (void)stopLevel{

  [[NSNotificationCenter defaultCenter] removeObserver:self name:UIDeviceBatteryLevelDidChangeNotification object:nil];
  

  }

• (void)stopLocation {

  [_locationManager stopUpdatingHeading];
  }

但是光传感器在