Proper way of using CLLocationManager (to start/stop updating user location)

问题

I have a UIView with an MKMapView, in a UIViewController, which appears only when user taps a button.

The process is as follows:

• A CLLocationManager object is declared as private member in the header file.
• A UIView with an MKMapView is presented (initially the frame is outside bounds. Is moved to within view bounds on user's action, WITHIN THE SAME viewController).

• It is initialized:

  locationManager = [[CLLocationManager alloc]  init];
  locationManager.distanceFilter = kCLDistanceFilterNone; // whenever we move
  locationManager.desiredAccuracy = kCLLocationAccuracyBest; // 100 m
  [locationManager startUpdatingLocation];
  CLLocation *location = [locationManager location];
  CLLocationCoordinate2D coordinate = [location coordinate];
  
  MKCoordinateSpan span = MKCoordinateSpanMake(0.04, 0.04);
  MKCoordinateRegion region = MKCoordinateRegionMake(coordinate, span);
  mapView.showsUserLocation = YES;
  [mapView setRegion:region animated:YES];
  

• Nearby locations are fetched using Foursquare API

Now, I wish to stop the location lock, when the view is removed from visible bounds. I tried it with stopUdatingUserLocation. I also released the locationManager, but the GPS lock icon is persistent in the statusBar. As I understand, continuous GPS lock drains the battery, and I would like to stop that. How would I go about it ?

回答1:

Even tho it's not officially documented, it would be better to use only one CLLocationManager throughout your whole app. Treat it as a singleton, don't initialise it every time, and it should work properly.

来源：https://stackoverflow.com/questions/18918019/proper-way-of-using-cllocationmanager-to-start-stop-updating-user-location