CLLocationManager not getting City name

问题

I am trying to get the current city and country using CLLocationManager with below code -

#pragma mark - Core Location Delegate Methods
- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
    CLGeocoder *reverseGeocoder = [[CLGeocoder alloc] init];

    [reverseGeocoder reverseGeocodeLocation:newLocation completionHandler:^(NSArray *placemarks, NSError *error)
     {
         NSLog(@"reverseGeocodeLocation:completionHandler: Completion Handler called!");
         if (error){
             NSLog(@"Geocode failed with error: %@", error);
             return;
         }

         NSLog(@"Received placemarks: %@", placemarks);


         CLPlacemark *myPlacemark = [placemarks objectAtIndex:0];
         NSString *countryCode = myPlacemark.ISOcountryCode;
         NSString *countryName = myPlacemark.country;
         NSString *city1 = myPlacemark.subLocality;
         NSString *city2 = myPlacemark.locality;
         NSLog(@"My country code: %@, countryName: %@, city1: %@, city2: %@", countryCode, countryName, city1, city2);
     }];
}

- (void)locationManager:(CLLocationManager *)manager didUpdateHeading:(CLHeading *)newHeading
{
    CLLocationDirection th=[newHeading trueHeading];
    NSLog(@"True Heading value is=%f",th);
    CLLocationDirection magnetic=[newHeading magneticHeading];
    NSLog(@"Magnetic Heading value is=%f",magnetic);
}

- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error
{
    NSString *errorType = (error.code == kCLErrorDenied) ? NSLocalizedString(@"access_denied", @"") : NSLocalizedString(@"unknown_error", @"");
    UIAlertView *alert = [[UIAlertView alloc]
                      initWithTitle:NSLocalizedString(@"error_getting_location", @"")
                      message:errorType
                      delegate:nil
                      cancelButtonTitle:NSLocalizedString(@"ok", @"")
                      otherButtonTitles:nil];
    [alert show];
}

It always gives the result with -

My country code: IN, countryName: India, city1: (null), city2: (null)

I don't know what may be the issue for this. Has anyone faced this issue that can't able to get the city name using CLLocationManager

回答1:

EDITED:

- (void) getReverseGeocode
{
    CLGeocoder *geocoder = [[CLGeocoder alloc] init];

    if(currentLatLong.count > 0)
    {
        CLLocationCoordinate2D myCoOrdinate;

        myCoOrdinate.latitude = LatValue;
        myCoOrdinate.longitude = LangValue;

        CLLocation *location = [[CLLocation alloc] initWithLatitude:myCoOrdinate.latitude longitude:myCoOrdinate.longitude];
        [geocoder reverseGeocodeLocation:location completionHandler:^(NSArray *placemarks, NSError *error)
         {
             if (error)
             {
                 NSLog(@"failed with error: %@", error);
                 return;
             }
             if(placemarks.count > 0)
             {
                 NSString *MyAddress = @"";
                 NSString *city = @"";

                 if([placemark.addressDictionary objectForKey:@"FormattedAddressLines"] != NULL)
                     MyAddress = [[placemark.addressDictionary objectForKey:@"FormattedAddressLines"] componentsJoinedByString:@", "];
                 else
                     MyAddress = @"Address Not founded";

                 if([placemark.addressDictionary objectForKey:@"SubAdministrativeArea"] != NULL)
                     city = [placemark.addressDictionary objectForKey:@"SubAdministrativeArea"];
                 else if([placemark.addressDictionary objectForKey:@"City"] != NULL)
                     city = [placemark.addressDictionary objectForKey:@"City"];
                 else if([placemark.addressDictionary objectForKey:@"Country"] != NULL)
                     city = [placemark.addressDictionary objectForKey:@"Country"];
                 else
                     city = @"City Not founded";

               NSLog(@"%@",city);
               NSLog(@"%@", MyAddress);
             }
         }];
    }
}

回答2:

You know about the apple maps and there database for the location, better try with google places api for getting more accurate and detailed information for reverse geocoding. I have tried same for auto filling the place names, but didn't worked,so went using google places api, there is one more free api try geonames.org

回答3:

in .h file

#import <CoreLocation/CoreLocation.h>

@interface ClassDemo : NSObject<NSXMLParserDelegate,CLLocationManagerDelegate>
{
BOOL got;
BOOL needParser;
NSMutableArray *currentplaceArray; 
}
@property (nonatomic, retain) CLLocation  *currentLocation;
@property (nonatomic, getter = isResultsLoaded) BOOL resultsLoaded;
@property (strong, nonatomic)  CLLocationManager *locationManager;
@property (strong, nonatomic) CLGeocoder *geoCoder;

in .m

@synthesize locationManager,currentLocation;
- (void)viewDidLoad 
{
 got=NO;
needParser=YES;

currentplaceArray=[[NSMutableArray alloc]init];
//******** Location MAnager Allocation And Intialization********//
locationManager = [[CLLocationManager alloc] init];
locationManager.delegate=self;
[locationManager startUpdatingLocation];
}
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
       fromLocation:(CLLocation *)oldLocation
{

if ([self isResultsLoaded])
{
    return;
}

[self setResultsLoaded:YES];

currentLocation = newLocation;
NSLog(@"%@",currentLocation);

NSXMLParser *parser = [[NSXMLParser alloc]initWithContentsOfURL:[NSURL URLWithString:[NSString stringWithFormat: @"http://maps.googleapis.com/maps/api/geocode/xml?latlng=%f,%f&sensor=false",newLocation.coordinate.latitude,newLocation.coordinate.longitude]]];

[parser setDelegate:self];
[parser parse];

}
-(void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict
{
NSLog(@"%@",elementName);
if([elementName isEqualToString:@"formatted_address"])
{
    got = YES; //got is a BOOL
}
}

-(void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string
{
if(got&&needParser){
    got=NO;
    NSLog(@"the address is = %@",string);
    NSArray *tempPlaceArray=[string componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@",/"]];
    NSLog(@"%@",tempPlaceArray);
    for(int i=0; i <[tempPlaceArray count]; i++)
    {


        NSString *tempString=[[tempPlaceArray objectAtIndex:i]stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
        NSLog(@"%@",tempString);
        if (![currentplaceArray containsObject:tempString])
        {
            if ([tempString length]!=0)
            {
                [currentplaceArray addObject:tempString];

            }
        }
    }
    needParser=NO;
    TempLocation *obj=[[TempLocation alloc]init];
    obj.countryName=[currentplaceArray objectAtIndex:[currentplaceArray count]-1];
    obj.stateName=[currentplaceArray objectAtIndex:[currentplaceArray count]-2];
    obj.cityName=[currentplaceArray objectAtIndex:[currentplaceArray count]-3];
    obj.fullAdd=string;
    [[Database getDBObject]insertIntoCurrentLocationTable:obj.cityName :obj.stateName :obj.countryName:obj.fullAdd];


}

}

make a temp location class for temporary storage. And you can also save to the database as. Enjoy Coding.

回答4:

Even I noticed same issue. After many trail and error I found the problem with wifi I was using. If the signal strength is low you'll get city as nil. Try changing your connection.

来源：https://stackoverflow.com/questions/15270527/cllocationmanager-not-getting-city-name