MKReverseGeocoder placemark为空

Question

我正在尝试获得一个位置的地标，但我得到的都是空的。这是我的头文件。

#import <Foundation/Foundation.h>
#import <MapKit/MapKit.h>


@interface ReverseGeoCodingHelper : NSObject<MKReverseGeocoderDelegate> {
    MKReverseGeocoder *reverseGeocoder;
    MKPlacemark *dootPlacemark;
}

@property (nonatomic, retain) MKReverseGeocoder *reverseGeocoder;
@property (nonatomic, retain) MKPlacemark *dootPlacemark;

- (void)reverseGeocode;

@end

这是我的.m文件

#import "ReverseGeoCodingHelper.h"

@implementation ReverseGeoCodingHelper
@synthesize reverseGeocoder,dootPlacemark;


- (void)reverseGeocode
{

    if (self.reverseGeocoder != nil)
    {
        // release the existing reverse geocoder to stop it running
        [self.reverseGeocoder release];
    }

    CLLocationCoordinate2D locationToLookup = {37.40091, -122.01635};

    self.reverseGeocoder =
    [[MKReverseGeocoder alloc]initWithCoordinate:locationToLookup];

    reverseGeocoder.delegate = self;
    [reverseGeocoder start];
}

// MKReverseGeocoderDelegate methods
/**
 Gets called when MKReverseGeocoder finds info for your coordinate, 
 you can retrieve info you need from corresponding fields of MKPlacemark instance you    
get
*/
- (void)reverseGeocoder:(MKReverseGeocoder *)geocoder  didFindPlacemark:(MKPlacemark  
*)placemark{

    NSString* city = [placemark.addressDictionary valueForKey:@"City"];
    NSString* street = [placemark.addressDictionary valueForKey:@"Street"]; 
    NSLog(@"Placemark is : @, @, @, @", [placemark country], [placemark locality], 
 city, street);
}
- (void)reverseGeocoder:(MKReverseGeocoder *)geocoder didFailWithError:(NSError *)error{
    NSString *errorMessage = [error localizedDescription];
        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Cannot obtain   
        address." message:errorMessage
                                                delegate:nil
                                          cancelButtonTitle:@"OK"
                                          otherButtonTitles:nil];
[alertView show];
[alertView release];
}

- (void)dealloc{
[reverseGeocoder release];
[super dealloc];
}

@end

正在调用didFindPlacemark方法，但是NSLog没有打印任何属性的值，它们都是空的。

Answer 1

在NSLog中，字符串变量的占位符应为%@ (而不仅仅是@)：

NSLog(@"Placemark is : %@, %@, %@, %@", [placemark country], 
    [placemark locality], city, street);