Getting Longitude/Latitude of the User When the vi

问题:

My purpose is to get the longitude/latitude of the user when the view is loaded and to store the values in two variables for later calculations. I don't need to track the user location and to update it, I simply need to get his/her coordinates once. My code looks like this:

- (void)viewDidLoad {
    [super viewDidLoad];
    // locationManager update as location
    locationManager = [[CLLocationManager alloc] init];
    locationManager.delegate = self; 
    locationManager.desiredAccuracy = kCLLocationAccuracyBest; 
    locationManager.distanceFilter = kCLDistanceFilterNone; 
    [locationManager startUpdatingLocation];
    CLLocation *location = [locationManager location];
    // Configure the new event with information from the location
    CLLocationCoordinate2D coordinate = [location coordinate];

    float longitude=coordinate.longitude;
    float latitude=coordinate.latitude;

    NSLog(@"dLongitude : %f",longitude);
    NSLog(@"dLatitude : %f", latitude); 
}

In the console i keep getting this:

dLongitude : 0.000000
dLatitude : 0.000000

Can you please help me there?

回答1:

To get user's location even once you need to make locationManager to start updating locations (you did that) and implement delegate method that manager calls when location is retrieved - you can't get location from location manager immediately.

If you don't want to track user location - just stop updating locations in that delegate method after location was fetched for the 1st time (and store it if you need it in future).

回答2:

As soon as you call [locationManager startUpdatingLocation]; your viewDidLoad method is done. You need to implement

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

and

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

which will be called by your locationManager when it gets the location, or when it fails. In both of those methods, you can call [locationManager stopUpdatingLocation].

Inside the didUpdateToLocation method, you should move all your code from viewDidLoad, starting with CLLocation *location = [locationManager location]; That's where you'll get proper values.

回答3:

This worked for me

- (void)viewDidLoad {
    [super viewDidLoad];
    // locationManager update as location
    locationManager = [[CLLocationManager alloc] init];
    locationManager.delegate = self; 
    locationManager.desiredAccuracy = kCLLocationAccuracyBest; 
    locationManager.distanceFilter = kCLDistanceFilterNone; 
    [locationManager startUpdatingLocation];
    [locationManager stopUpdatingLocation];
    CLLocation *location = [locationManager location];
    // Configure the new event with information from the location

    float longitude=location.coordinate.longitude;
    float latitude=location.coordinate.latitude;

    NSLog(@"dLongitude : %f", longitude);
    NSLog(@"dLatitude : %f", latitude); 
}

回答4:

Try this Code

-(IBAction)Button:(id)sender

{

locationManager = [[CLLocationManager alloc] init]; 

locationManager.delegate = self;

locationManager.desiredAccuracy = kCLLocationAccuracyBest;

locationManager.distanceFilter = kCLDistanceFilterNone;

[locationManager startUpdatingLocation];

CLLocation *location = [locationManager location];

// Configure the new event with information from the location

CLLocationCoordinate2D coordinate = [location coordinate];

NSString *latitude = [NSString stringWithFormat:@"%f", coordinate.latitude];

NSString *longitude = [NSString stringWithFormat:@"%f", coordinate.longitude];

NSLog(@"dLatitude : %@", latitude);

NSLog(@"dLongitude : %@",longitude);

UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(50, 40, 250, 50)];

UILabel *myLabel = [[UILabel alloc] initWithFrame:CGRectMake(50, 80, 200, 50)];

UILabel *myLabel1 = [[UILabel alloc] initWithFrame:CGRectMake(50, 120, 200, 100)];

myLabel.textColor = [UIColor blackColor];

myLabel1.textColor = [UIColor blackColor];

label.backgroundColor = [UIColor clearColor];

myLabel.backgroundColor = [UIColor clearColor];

myLabel1.backgroundColor = [UIColor clearColor];

[myLabel setText:latitude];

[myLabel1 setText:longitude];

label.text = @"Current Latitude And Longitude";

[self.view addSubview:label];

[self.view addSubview:myLabel];

[self.view addSubview:myLabel1];

}

回答5:

if you are getting Lat lang both (0.00 ,0.00)

this may be solution for your ,

step 1: NSLocationAlwaysUsageDescription or NSLocationWhenInUseUsageDescription

Add these two key in Info.plist

step 2: And than [locationManager startUpdatingLocation]; start updating

step 3: and you need to implement two mehthods

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

}

-(void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations{



 CLLocation * currentLocation = [locations lastObject];

    NSLog(@"Updated Lat %f",currentLocation.coordinate.longitude);
    NSLog(@"Updated Lang %f",currentLocation.coordinate.latitude);



}

of CLLocationManagerDelegate in your ViewController interface.

**step 4:**

-(void)viewDidLoad
{
    [super viewDidLoad];
 geocoder = [[CLGeocoder alloc] init];
    manager.delegate = self;
    manager.desiredAccuracy = kCLLocationAccuracyBest;
    [manager requestWhenInUseAuthorization];
    [manager requestAlwaysAuthorization];
    [manager startUpdatingLocation];


}