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];}