Question

I am developing an iPhone application in which I want to show nearest restaurants based on the current location
For that In the applicationDidFinishLaunching I am doing this :

self.locationManager = [[CLLocationManager alloc] init];

    locationManager.delegate = self;
    locationManager.desiredAccuracy = kCLLocationAccuracyBest;
    [locationManager startUpdatingLocation];



    NSURL *url = [[NSURL alloc] initWithString:@"http://192.168.0.150/server1/Service.asmx/nearest?lat1=23.013163&lon1=72.559068"];
    NSMutableURLRequest* request2=[NSMutableURLRequest requestWithURL:url];
    [request2 setHTTPMethod:@"GET"]; 
    [request2 setTimeoutInterval:10];
    NSURLResponse *response=nil;
    NSError *err=nil;
    NSData *data1=[[NSURLConnection sendSynchronousRequest:request2 returningResponse:&response error:&err] retain];
    if(data1 == nil)
    {
        UIAlertView* alert = [[UIAlertView alloc]initWithTitle:@"Alert" message:@"The network is not available.\n Please check the Internet connection." delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
        [alert show];
        [alert release];

    }
    else
    {
        NSXMLParser *xmlParser = [[NSXMLParser alloc] initWithData:data1];

        //Initialize the delegate.
        XMLParser *parser = [[XMLParser alloc] initXMLParser];

        //Set delegate
        [xmlParser setDelegate:parser];

        //Start parsing the XML file.
        @try {
            BOOL success = [xmlParser parse];
            if(success)
                NSLog(@"No Errors");
            else
                NSLog(@"Error Error Error!!!");
        }
        @catch (NSException * e) {
            NSLog(@"Exception in parsing %@  %@",[e name], [e reason]);
        }
    }

The problem scenario.

the location manager start updating the location

The webservice gets executed before that so I can’t get the location values .

I I am putting the web service call in the delegate method then the application launches before the web service gets executed.
in the delegate method I am setting the latitude and longitude in the appropriate strings.

The Problem is that how ensure that the service will not be called until the location manager updates that location and then pass the location to the web service and then call that web service ..

Answer 1

CLLocationManaged has the delegate method.

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

it will be called when CLLocationManager will receive some coordinates. Or

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

it will be called when locationManager cannot receive any coordinates. Or when user don’t allow to find current location. Also you should call stopUpdatingLocation if you don’t want to receive more accurate results.

So you can make your request inside delegate method to be sure is will be called only after updating current location.