MKLocalSearch reverse zip code lookup

ViewController.m

//
//  ViewController.m
//  Ziptastic
//
//  Created by Ben Lindsey on 3/20/14.
//  Copyright (c) 2014 Ben Lindsey. All rights reserved.
//

#import "ViewController.h"
#import <MapKit/MapKit.h>

@interface ViewController ()

@property (weak, nonatomic) IBOutlet UITextField *zipField;
@property (weak, nonatomic) IBOutlet UILabel *resultLabel;
@property (strong, nonatomic) IBOutlet NSRegularExpression *regex;

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.zipField.delegate = self;
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    return [string length] == 0 || [[[NSNumberFormatter alloc] init] numberFromString:string] != nil;
}

- (BOOL)textFieldShouldReturn:(UITextField *)textField
{
    [textField resignFirstResponder];
    return YES;
}

- (void)textFieldDidEndEditing:(UITextField *)textField
{
    MKLocalSearchRequest *request = [[MKLocalSearchRequest alloc] init];
    request.naturalLanguageQuery = textField.text;
    MKLocalSearch *search = [[MKLocalSearch alloc] initWithRequest:request];
    [search startWithCompletionHandler:^(MKLocalSearchResponse *response, NSError *error) {
        self.resultLabel.text = @"Zip Lookup Failed";
        if ([response.mapItems count] > 0) {
            MKMapItem *item = response.mapItems[0];
            NSString *name = item.name;
            NSArray *matches = [self.regex matchesInString:name options:0 range:NSMakeRange(0, [name length])];
            if ([matches count] == 1) {
                NSTextCheckingResult *match = matches[0];
                NSLog(@"City=%@ State=%@ Zip=%@", [name substringWithRange:[match rangeAtIndex:1]], [name substringWithRange:[match rangeAtIndex:2]], [name substringWithRange:[match rangeAtIndex:3]]);
                self.resultLabel.text = name;
            }
        }
    }];
}

- (NSRegularExpression *)regex
{
    if (!_regex) {
        NSError *error = NULL;
        _regex = [NSRegularExpression regularExpressionWithPattern:@"^(.*),\\s*(\\w{2})\\s*(\\d{5})" options:0 error:&error];
        if (error) NSLog(@"Regex error: %@", error);
    }
    return _regex;
}

@end