ios - 如果地址行不存在则将其设为空白(Objective-C)

Question

我的应用找到用户的位置，并在标签中显示地址。问题是如果某个地方不存在某些东西，例如邮政编码，那么该行会显示 (null)。我如何使该行空白？我想它必须以某种方式在某处设置为 nil...

请帮忙!

这是我的代码:

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {

NSLog(@"Location: %@", newLocation);
CLLocation *currentLocation = newLocation;

[geoCoder reverseGeocodeLocation:currentLocation completionHandler:^(NSArray<CLPlacemark *> * _Nullable placemarks, NSError * _Nullable error) {

    if (error == nil && [placemarks count] > 0) {

        placeMark = [placemarks lastObject];

        NSString *locationString = [NSString stringWithFormat:@"%@ %@\n%@ %@\n%@\n%@",
                                    placeMark.subThoroughfare,
                                    placeMark.thoroughfare,
                                    placeMark.postalCode,
                                    placeMark.locality,
                                    placeMark.administrativeArea,
                                    placeMark.country];

        locationLabel.text = locationString;

    }

    else {

        NSLog(@"%@", error.debugDescription);

    }

}];

}

Answer 1

此代码检查所有字段是否为 nil(这会导致 <null> 输出)并替换 nil带有空字符串的值。

  NSString *locationString = [NSString stringWithFormat:@"%@ %@\n%@ %@\n%@\n%@",
                                placeMark.subThoroughfare ?: @"",
                                placeMark.thoroughfare ?: @"",
                                placeMark.postalCode ?: @"",
                                placeMark.locality ?: @"",
                                placeMark.administrativeArea ?: @"",
                                placeMark.country ?: @""];