IOS中的位置服务，提示

Question

My application needs the location services to work, so therefore the user gets asked the question when the application is first run. If the user says 'OK' then it will run the whole application without it on, because it will continue doing its work. So the first run it doesn't really bring anything on the view controller.

When I press the go button in XCODE the second time, it works fine because the user has already authorised the use of location services to get lat/long.

Has anyone had this problem before ? Any advice ?

Answer 1

In your viewDidLoad:

locationManager = [[CLLocationManager alloc] init];
[locationManager setDelegate:self];
[locationManager setDistanceFilter:kCLDistanceFilterNone];
[locationManager setDesiredAccuracy:kCLLocationAccuracyBest];
[locationManager startUpdatingLocation];

Answer 2

What you need to do, is update your view after the "didUpdateLocation" calls, and call "SetNeedsDisplay", so your view will draw itself to update. Like so:

-(void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation
{

    self.LabellLatitude = [NSString stringWithFormat:@"%f",self.locationManager.location.coordinate.latitude];
    self.LabelLongitude = [NSString stringWithFormat:@"%f",self.locationManager.location.coordinate.longitude];
    [self.view setNeedsDisplay];

}

Even better if you add a activity indicator intill the location updates.

Now, if your calling this from your "AppDelegate" class, you can use "NSNotificationCenter" to send message to your view, to update the labels, or view, or whatever you need, like so:

#pragma mark - locationManager:
-(void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation
{

    [[NSNotificationCenter defaultCenter] postNotificationName:@"UpdatedLocation" object:nil userInfo:dictionary];


} 

And on your UIVIewController ViewDidLoad, user this to register to the notificaitons:

 //Adding self to notification Center:
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(updateView:) name:@"UpdatedLocation" object:nil];

Hope this helps