地理编码到UITextfield不会显示

Question

I am using reverse geocoding which works but I am trying to separate the attributes. For example I want to have zip code displayed in it's own text field.

This is what I've tried but I get a breakpoint at if([placemarks count] >0)

- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{

    // Make sure this is a recent location event
    CLLocation *newLocation = [locations lastObject];
    NSTimeInterval eventInterval = [newLocation.timestamp timeIntervalSinceNow];
    if(abs(eventInterval) < 30.0)
    {
        // Make sure the event is valid
        if (newLocation.horizontalAccuracy < 0)
            return;

        // Instantiate _geoCoder if it has not been already
        if (_geocoder == nil)
            _geocoder = [[CLGeocoder alloc] init];

        //Only one geocoding instance per action
        //so stop any previous geocoding actions before starting this one
        if([_geocoder isGeocoding])
            [_geocoder cancelGeocode];

        [_geocoder reverseGeocodeLocation: newLocation
                        completionHandler: ^(NSArray* placemarks, NSError* error)
         {
             if([placemarks count] > 0)
             {
                 CLPlacemark *foundPlacemark = [placemarks objectAtIndex:0];

                 self.address.text =
                 [NSString stringWithFormat:@"%@",
                  foundPlacemark.description];

                 self.zip.text =
                 [NSString stringWithFormat:@"%@",
                  foundPlacemark.postalCode];



             }
             else if (error.code == kCLErrorGeocodeCanceled)
             {
                 NSLog(@"Geocoding cancelled");
             }
             else if (error.code == kCLErrorGeocodeFoundNoResult)
             {
                 self.address.text=@"No geocode result found";
             }
             else if (error.code == kCLErrorGeocodeFoundPartialResult)
             {
                 self.address.text=@"Partial geocode result";
             }
             else
             {
                 self.address.text =
                 [NSString stringWithFormat:@"Unknown error: %@",
                  error.description];
             }
         }
         ];

Answer 1

Try to handle error first by checking if its nil:

if (error) {
    // handle here
    NSLog(@"error: %@", error);
    return; // exit statement 
} 

// handle code here if there was no error

and avoid strong reference cycles create a weak object of your self, when calling a object use this instnace.

__weak typeof(self) weakSelf = self;

so self.address.text=@"Partial geocode result"; will turn to weakSelf.address.text=@"some text here...";