1.這只是導航欄上面的運用

在這機上會自動獲取當前的城市

   //1.掛代理 CLLocationManagerDelegate
   導入#import <CoreLocation/CoreLocation.h>
   //兩個屬性
   NSString *Citystring;// 城市名
   @property(nonatomic,strong) CLLocationManager *locationManger;
   @property(nonatomic,strong) CLGeocoder *geocoder;

  #pragma mark 用戶對地理位置的確定
  -(CLGeocoder *)geocoder
  {
        if (!_geocoder) {
           _geocoder = [[CLGeocoder alloc]init];
        }
        return _geocoder;
  }

  //1.創(chuàng)建定位管理者
  -(CLLocationManager *)locationManger
  {
         if (!_locationManger) {
            _locationManger = [[CLLocationManager alloc]init];
         }
        return _locationManger;
  }

#pragma mark - 定位
-(void)CityLoation
{
self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc]initWithTitle:@"定位" style:UIBarButtonItemStylePlain target:self action:@selector(clickStatee)];
//2.掛代理
self.locationManger.delegate = self;
//3.對設備進行判斷,因為安全要求高了(記得在Info.plist里面進行配置requestAlwaysAuthorization點擊進去配置)

if ([[UIDevice currentDevice].systemVersion doubleValue]>=8.0) {
    
    NSLog(@"這是iOS8設備");
    [self.locationManger requestAlwaysAuthorization];
    }else
    {
          NSLog(@"不是iOS8的設備");
    }
 }

//4.狀態(tài)監(jiān)聽
-(void)locationManager:(CLLocationManager *)manager didChangeAuthorizationStatus:(CLAuthorizationStatus)status
{

if (status == kCLAuthorizationStatusNotDetermined) {
    DFTLog(@"等待授權");
}else if (status == kCLAuthorizationStatusAuthorizedAlways || status == kCLAuthorizationStatusAuthorizedWhenInUse )
{
    DFTLog(@"授權成功");
    //始終
    
    //        self.locationManger.desiredAccuracy = kCLLocationAccuracyBest;
    //        self.locationManger.distanceFilter = 10.0f;
    [self.locationManger startUpdatingLocation];
}
    else
   {
        DFTLog(@"定位失敗");
   }
}

//5.調(diào)用定位信息
-(void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray<CLLocation *> *)locations
{
    CLLocation *location = [locations lastObject];
    [self.geocoder reverseGeocodeLocation:location completionHandler:^(NSArray<CLPlacemark *> * _Nullable placemarks, NSError * _Nullable error) {
    
    for (CLPlacemark *placemark in placemarks) {
        //接收定位出來的地理位置
        Citystring = placemark.locality;
        DFTLog(@"=====%@",Citystring);
        self.navigationItem.leftBarButtonItem.title = Citystring;
      }
   }];
      [self.locationManger stopUpdatingLocation];(定位成功我們要關閉定位,減少性能的消耗)
}

3.點擊上面的定位,我們可以自己獲取位置

這時我們需要導入一個封裝好的類 城市選擇框架
#import "CityViewController.h"

點擊上面的定位選擇地理位置

#pragma mark - 城市選擇
-(void)clickStatee
{
      CityViewController *controller = [[CityViewController alloc] init];    
      這個賦值是當前這個控制器的位置帶到這個框架里面去,顯示當前的位置
      controller.currentCityString = Citystring;
      //block傳值(把值帶出來)
      controller.selectString = ^(NSString *string){
      self.navigationItem.leftBarButtonItem.title = string;
      };
      [self presentViewController:controller animated:YES completion:nil];
}