{  self.locationManager = [[CLLocationManager alloc] init];  _locationManager.delegate = self;  if([CLLocationManager locationServicesEnabled] == NO) {   //  NSLog(@"沒有GPS服務");  }  //地理位置精確度  _locationManager.desiredAccuracy=kCLLocationAccuracyNearestTenMeters;  //設置距離篩選器,double類型,只要距離變化多少,就調用委托代理  self.locationManager.distanceFilter = kCLDistanceFilterNone; // meters  [_locationManager requestWhenInUseAuthorization];// 前臺定位  [_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;    //將經度顯示到label上    _longitudeLabel.text = [NSString stringWithFormat:@"%f",longTI];    //將緯度現實到label上    _latitudeLabel.text = [NSString stringWithFormat:@"%f",latTI];  // 獲取當前所在的城市名  CLGeocoder *geocoder = [[CLGeocoder alloc] init];  //根據經緯度反向地理編譯出地址信息  [geocoder reverseGeocodeLocation:locations.lastObject completionHandler:^(NSArray *array, NSError *error)   {     if (array.count > 0)     {       CLPlacemark *placemark = [array objectAtIndex:0];//       //將獲得的所有信息顯示到label上//       self.location.text = placemark.name;       //獲取城市       NSString *city = placemark.locality;       if (!city) {         //四大直轄市的城市信息無法通過locality獲得，只能通過獲取省份的方法來獲得（如果city為空，則可知為直轄市）         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);     }   }];  //系統會一直更新數據，直到選擇停止更新，因為我們只需要獲得一次經緯度即可，所以獲取之后就停止更新  [manager stopUpdatingLocation];}