使用CLLocationManager和MKReverseGeocoder获取城市名称

Question

我试图通过使用MKReverseGeoCoder获取用户当前位置的城市名称,但它有一些我无法识别的错误.以下是详细信息:

它有一些我无法识别的错误

Undefined symbols:
  ".objc_class_name_CLLocationManager", referenced from:
      literal-pointer@__OBJC@__cls_refs@CLLocationManager in mapViewController.o
  "_kCLLocationAccuracyNearestTenMeters", referenced from:
      _kCLLocationAccuracyNearestTenMeters$non_lazy_ptr in mapViewController.o
ld: symbol(s) not found
collect2: ld returned 1 exit status

在这里;我的代码:

mapViewController.m

//
//  mapViewController.m
//  map
//
//  Created by Ashutosh Tiwari on 7/23/10.
//  Copyright ISU 2010. All rights reserved.
//
#import <MapKit/MapKit.h>
#import "mapViewController.h"

@implementation mapViewController


// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
    CLLocationManager *locationManager = [[[CLLocationManager alloc] init] autorelease];
    locationManager.delegate = self;
    locationManager.desiredAccuracy = kCLLocationAccuracyNearestTenMeters;
    [locationManager startUpdatingLocation];

    [super viewDidLoad];
}

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

    MKReverseGeocoder *geoCoder = [[MKReverseGeocoder alloc] initWithCoordinate:newLocation.coordinate];
    geoCoder.delegate = self;
    [geoCoder start];
}

- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error 
{
    NSLog(@"locationManager:%@ didFailWithError:%@", manager, error);
}

- (void)reverseGeocoder:(MKReverseGeocoder *)geocoder didFindPlacemark:(MKPlacemark *)placemark
{
    MKPlacemark * myPlacemark = placemark;

    NSString *kABPersonAddressCityKey;
    NSString *city = [myPlacemark.addressDictionary objectForKey:(NSString*) kABPersonAddressCityKey];
}

- (void)reverseGeocoder:(MKReverseGeocoder *)geocoder didFailWithError:(NSError *)error
{
    NSLog(@"reverseGeocoder:%@ didFailWithError:%@", geocoder, error);
}

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

@end

Answer 1

添加CoreLocation.framework到项目的链接(目标设置/链接库/添加/选择CoreLocation.framework)

添加:简要说明每种方法的作用:

• viewDidLoad:
  创建CLLocationManager实例并开始更新位置 - 获取当前用户坐标

• locationManager:didUpdateToLocation:
  当CLLocationManager接收用户坐标时调用.现在我们可以传递它们以MKReverseGeocoder获取用户位置(国家,城市等)的信息

• locationManager:didFailWithError:并reverseGeocoder:didFailWithError:
  处理可能的错误 - 只需将它们记录在当前实现中

• reverseGeocoder:didFindPlacemark:
  在MKReverseGeocoder找到坐标信息时调用,您可以从MKPlacemark实例的相应字段中检索所需的信息.

kABPersonAddressCityKey - 是地标地址字典中City字段的关键字符串.它在ABPerson.h头文件中定义,因为placemark和ABRecord地址的地址字段是相同的.因此,要使用该密钥,您可能还需要与AddressBook框架链接.