How Can I Get Current Location on iOS? [duplicate]

问题:

This question already has answers here:

how to get the current location position in map on iphone (2 answers)

Closed 6 years ago.

I can't get current location. When I launch my app in different place, App can get last location. But I don't want to last location. If you close the app and restart it, now app can get current location. How can I get current location even if it is first launch of application?

- (void)viewDidLoad
{
    [super viewDidLoad];

    [locationManager startUpdatingLocation];

    self.mapView.delegate = self;
    [self.mapView setShowsUserLocation:YES];

    locationManager.delegate=self;

    locationManager = [[CLLocationManager alloc] init];

    locationManager.delegate=self;
    locationManager.desiredAccuracy=kCLLocationAccuracyBest;
    locationManager.distanceFilter=kCLDistanceFilterNone;

    location = [locationManager location];

    CLLocationCoordinate2D coord;
    coord.longitude = location.coordinate.longitude;
    coord.latitude = location.coordinate.latitude;
    lat = coord.latitude;
    longt = coord.longitude;
}

回答1:

You are doing [locationManager startUpdatingLocation]; before setting its delegate

locationManager = [[CLLocationManager alloc] init];
locationManager.delegate=self;
locationManager.desiredAccuracy=kCLLocationAccuracyBest;
locationManager.distanceFilter=kCLDistanceFilterNone;

[locationManager startUpdatingLocation];

And implement its delegate method

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

- (void)locationManager:(CLLocationManager *)manager
       didFailWithError:(NSError *)error
{

}

回答2:

For getting current location as well as its coordinates,you just have to do only this in your viewDidLoad method :

- (void)viewDidLoad {
  [super viewDidLoad];
  locationManager = [[CLLocationManager alloc] init];
  locationManager.delegate = self;
  locationManager.distanceFilter = kCLDistanceFilterNone; // whenever we move
  locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters; // 100 m
  [locationManager startUpdatingLocation];
}

And about updating location,use this method :

    - (void)locationManager:(CLLocationManager *)manager
        didUpdateToLocation:(CLLocation *)newLocation
               fromLocation:(CLLocation *)oldLocation{
// your code here...
}

回答3:

You should read the documentation provided in the Location Awareness Programming Guide.

Specifically, when you ask for the current location, the system returns the last known location right away so you can do something useful with it. If you don't care about past locations, you can discard it and only use more recent location information by looking at the timestamp property of the CLLocation returned to determine how recent it is.

回答4:

You should really read the CLLocationManager documentation.

Wat you are doing will not work, since it will take some time determine the device location. Therefor you will need to wait until the CLLocationManager notifies you that a location has been determent.

You will need to implement the CLLocationManagerDelegate which will tell you if a location is determent or if the location determination failed.

Also you should also check if location can be determent with:

if ([CCLocationManager locationServicesEnabled]) {
    // The location services are available.
}

You should also check wether you are authorize to use the location services with [CCLocationManager authorizationStatus].