1.这只是导航栏上面的运用

在这机上会自动获取当前的城市

   //1.挂代理 CLLocationManagerDelegate
   导入#import <CoreLocation/CoreLocation.h>
   //两个属性
   NSString *Citystring;// 城市名
   @property(nonatomic,strong) CLLocationManager *locationManger;
   @property(nonatomic,strong) CLGeocoder *geocoder;

  #pragma mark 用户对地理位置的确定
  -(CLGeocoder *)geocoder
  {
        if (!_geocoder) {
           _geocoder = [[CLGeocoder alloc]init];
        }
        return _geocoder;
  }

  //1.创建定位管理者
  -(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.挂代理
self.locationManger.delegate = self;
//3.对设备进行判断,因为安全要求高了(记得在Info.plist里面进行配置requestAlwaysAuthorization点击进去配置)

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

//4.状态监听
-(void)locationManager:(CLLocationManager *)manager didChangeAuthorizationStatus:(CLAuthorizationStatus)status
{

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

//5.调用定位信息
-(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) {
        //接收定位出来的地理位置
        Citystring = placemark.locality;
        DFTLog(@"=====%@",Citystring);
        self.navigationItem.leftBarButtonItem.title = Citystring;
      }
   }];
      [self.locationManger stopUpdatingLocation];(定位成功我们要关闭定位,减少性能的消耗)
}

3.点击上面的定位,我们可以自己获取位置

这时我们需要导入一个封装好的类 城市选择框架
#import "CityViewController.h"

点击上面的定位选择地理位置

#pragma mark - 城市选择
-(void)clickStatee
{
      CityViewController *controller = [[CityViewController alloc] init];    
      这个赋值是当前这个控制器的位置带到这个框架里面去,显示当前的位置
      controller.currentCityString = Citystring;
      //block传值(把值带出来)
      controller.selectString = ^(NSString *string){
      self.navigationItem.leftBarButtonItem.title = string;
      };
      [self presentViewController:controller animated:YES completion:nil];
}