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   正在进行的项目中有这样的需求：定位获得当前经纬度，再用百度Place API使用经纬度查询周边信息。这里不需要显示地图，只需要定位。看似思路很顺畅，做起来却不容易。
  iPhone的GPS定位(CLLocationManager)获得的经纬坐标是基于WGS-84坐标系（世界标准），Google地图使用的是GCJ-02坐标系（中国特色的火星坐标系），这就是为什么获得的经纬坐标在google地图上会发生偏移。我项目需求是使用百度Place API，百度的经纬坐标在GCJ-02的基础上再做了次加密，就是DB-09坐标系。就想使用百度地图的[iOS](http://lib.csdn.net/base/ios) SDK，里面的坐标系统都是一致的而不用转换，由于不想让项目太大，所以没有用百度的sdk，所以另辟蹊径了。
   在网上搜索一番，有现成百度的接口转换坐标，经试验 从WGS-84到GCJ-02，再到DB-09，经两次转换后，顺利获得当前正确地理位置信息和周边信息，当然这些信息是来自百度的。

ZYLocationManager.h

[objc] view plain copy

import <Foundation/Foundation.h>

import <CoreLocation/CoreLocation.h>

import "Singleton.h"

typedef void(^locationBlock)(CLLocationCoordinate2D coor);
typedef void(^addressBlock)(NSString *address);

@interface ZYLocationManager : NSObject
singleton_interface(ZYLocationManager)

/**

• 获取纠偏后的经纬度(百度地图经纬度)
  */

• (void) getLocationCoordinate:(locationBlock) locaiontBlock;

/**

• 获取纠偏后的经纬度(百度地图经纬度)和地址
  */

• (void) getLocationCoordinate:(locationBlock) locaiontBlock address:(addressBlock) addressBlock;

@end

ZYLocationManager.m

[objc] view plain copy

import "ZYLocationManager.h"

import "AFNetworking.h"

define IOS_Version [[UIDevice currentDevice].systemVersion floatValue]

@interface ZYLocationManager ()<CLLocationManagerDelegate>{
// 保存block
locationBlock _locationBlock;
addressBlock _addressBlock;
}

@property (nonatomic, strong) CLLocationManager *lm;

@end

@implementation ZYLocationManager
singleton_implementation(ZYLocationManager)

/**

• 懒加载
  */

• (CLLocationManager *)lm
  {
  if (!_lm) {
  _lm = [[CLLocationManager alloc] init];
  _lm.delegate = self;
  // 定位精准度
  _lm.desiredAccuracy = kCLLocationAccuracyBest;
  // 重新定位的距离
  _lm.distanceFilter = 1000.0f;
  }
  return _lm;
  }

/**

• 类第一次使用的时候被调用
  */

• (void)initialize
  {
  ZYLocationManager *manager = [self sharedZYLocationManager];
  // ios8后需要向用户请求权限
  if (IOS_Version >= 8.0) {
  [manager.lm requestWhenInUseAuthorization];
  [manager.lm requestAlwaysAuthorization];
  }
  // 开始定位
  [manager.lm startUpdatingLocation];
  }

pragma mark - CLLocationManager获取经纬度的代理方法

• (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
  {
  CLLocation *location = [locations lastObject];
  CLLocationCoordinate2D coor = location.coordinate;
  // NSLog(@"纬度：%.6f 经度%.6f", coor.latitude, coor.longitude);
  NSString *x1 = [NSString stringWithFormat:@"%f", coor.longitude];
  NSString *y1 = [NSString stringWithFormat:@"%f", coor.latitude];
  // http://api.map.baidu.com/ag/coord/convert?from=0&to=2&x=113.377346&y=23.132648
  __block NSDictionary *dict1 = @{@"from":@"0",
  @"to":@"2",
  @"x":x1,
  @"y":y1
  };
  AFHTTPRequestOperationManager *roManager = [AFHTTPRequestOperationManager manager];
  // 1、ios系统经纬度（国际标准）转谷歌经纬度
  [roManager GET:@"http://api.map.baidu.com/ag/coord/convert" parameters:dict1 success:^(AFHTTPRequestOperation *operation, id responseObject) {
  __block NSString *resultX = [self base64Decode:responseObject[@"x"]];
  __block NSString *resultY = [self base64Decode:responseObject[@"y"]];
  dict1 = @{@"from":@"2",
  @"to":@"4",
  @"x":resultX,
  @"y":resultY
  };

    // 2、谷歌经纬度转百度经纬度  
    [roManager GET:@"http://api.map.baidu.com/ag/coord/convert" parameters:dict1 success:^(AFHTTPRequestOperation *operation, id responseObject) {  
        resultX = [self base64Decode:responseObject[@"x"]];  
        resultY = [self base64Decode:responseObject[@"y"]];  
        CLLocationCoordinate2D resultCoor = CLLocationCoordinate2DMake([resultY floatValue], [resultX floatValue]);  
        // 给block赋值  
        if (_locationBlock) {  
            _locationBlock(resultCoor);  
        }  
        [self getAddressWithCoordinate:resultCoor];  
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {  
        NSLog(@"%@", error);  
    }];  
  

  } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
  NSLog(@"%@", error);
  }];
  // 停止定位
  [self.lm stopUpdatingLocation];
  }

• (void)getLocationCoordinate:(locationBlock)locaiontBlock
  {
  _locationBlock = locaiontBlock;
  }

• (void)getLocationCoordinate:(locationBlock)locaiontBlock address:(addressBlock)addressBlock
  {
  _locationBlock = locaiontBlock;
  _addressBlock = addressBlock;
  }

pragma mark - base64解密

• (NSString *)base64Decode:(NSString *)str
  {
  // 1、加密字符串转二进制数据
  NSData *data = [[NSData alloc] initWithBase64EncodedString:str options:NSDataBase64DecodingIgnoreUnknownCharacters];
  // 2、二进制数据转字符串
  return [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
  }

pragma mark - 经纬度转地址

• (void)getAddressWithCoordinate:(CLLocationCoordinate2D)coor
  {
  if (coor.latitude == 0 || coor.longitude == 0) return;

  CLLocation *loca = [[CLLocation alloc] initWithLatitude:coor.latitude longitude:coor.longitude];
  CLGeocoder *geocoder = [[CLGeocoder alloc] init];
  [geocoder reverseGeocodeLocation:loca completionHandler:^(NSArray *placemarks, NSError *error) {
  if (placemarks.count == 0 || error) return;

    CLPlacemark *pm = [placemarks lastObject];  
    if (_addressBlock) {  
        _addressBlock(pm.thoroughfare);  
    }  
  

  }];
  }

@end

IOS8后，请求定位需要请求权限，代码ZYLocationManager.m已经写好了，不过还需要在info.plist中，添加两个属性NSLocationAlwaysUsageDescription和NSLocationWhenInUseUsageDescription，属性值即是你需要提示给用户的信息，如下图所示：

将ZYLocationManager.h和ZYLocationManager.m拖入项目中，即可直接调用ZYLocationManager.h定义的两个方法，获取到百度经纬度和地址。

原文出处： http://blog.csdn.net/u013454067/article/details/45131387