IOS开发笔记整理49之详解定位CLLocation

{
  self.locationManager = [[CLLocationManager alloc] init];
  _locationManager.delegate = self;
  if([CLLocationManager locationServicesEnabled] == NO) {
   //  NSLog(@"没有GPS服务");
  }
  //地理位置精确度
  _locationManager.desiredAccuracy=kCLLocationAccuracyNearestTenMeters;
  //设置距离筛选器,double类型,只要距离变化多少,就调用委托代理
  self.locationManager.distanceFilter = kCLDistanceFilterNone; // meters
  [_locationManager requestWhenInUseAuthorization];// 前台定位
  [_locationManager startUpdatingLocation];
}
- (void)locationManager:(CLLocationManager *)manager
   didUpdateLocations:(NSArray *)locations
{
  NSLog(@"longitude = %f", ((CLLocation *)[locations
                       lastObject]).coordinate.longitude);
  NSLog(@"latitude = %f", ((CLLocation *)[locations lastObject]).coordinate.latitude);
    CGFloat longTI=((CLLocation *)[locations
                    lastObject]).coordinate.longitude;
    CGFloat latTI=((CLLocation *)[locations lastObject]).coordinate.latitude;
    //将经度显示到label上
    _longitudeLabel.text = [NSString stringWithFormat:@"%f",longTI];
    //将纬度现实到label上
    _latitudeLabel.text = [NSString stringWithFormat:@"%f",latTI];
  // 获取当前所在的城市名
  CLGeocoder *geocoder = [[CLGeocoder alloc] init];
  //根据经纬度反向地理编译出地址信息
  [geocoder reverseGeocodeLocation:locations.lastObject completionHandler:^(NSArray *array, NSError *error)
   {
     if (array.count > 0)
     {
       CLPlacemark *placemark = [array objectAtIndex:0];
//       //将获得的所有信息显示到label上
//       self.location.text = placemark.name;
       //获取城市
       NSString *city = placemark.locality;
       if (!city) {
         //四大直辖市的城市信息无法通过locality获得，只能通过获取省份的方法来获得（如果city为空，则可知为直辖市）
         city = placemark.administrativeArea;
       }
      // NSLog(@"city = %@", city);
       _cityName=city;
     }
     else if (error == nil && [array count] == 0)
     {
      // NSLog(@"No results were returned.");
     }
     else if (error != nil)
     {
      // NSLog(@"An error occurred = %@", error);
     }
   }];
  //系统会一直更新数据，直到选择停止更新，因为我们只需要获得一次经纬度即可，所以获取之后就停止更新
  [manager stopUpdatingLocation];
}