CLGeocoder fails silently
I’m currently developing a location-based app for iPad and iPhone, that will allow users to store locations and use custom icons and colors for the pins.
This is how it currently looks:
In the app, you can pin your location, pin any place by pressing the map or search for an address, which uses CLGeocoder to find a coordinate for an address.
Searching for addresses hasn’t been working great, though. If I search for a street in my current city, I get results in other towns.
For clarity, this is the exact method body I use to kick off a search operation:
CLLocationCoordinate2D *coord = self.mapView.userLocation.location.coordinate;
CLRegion *region = [[CLRegion alloc] initCircularRegionWithCenter:coord
radius:10000
identifier:nil];
id<ForwardGeocoder> geocoder = [ObjectFactory getForwardGeocoder];
geocoder.delegate = self;
[geocoder encodeAddressString:self.searchBar.text inRegion:region];
I first accepted the bad result as a limitation in CLGeocoder’s Swedish geocoding abilities, but then noticed that the same problem occurred for American addresses as well.
As I couldn’t get things to work, I decided to return to the Google-based geocoder I used before - Björn Sållarp’s BSGeocoder. I tried CLGeocoder, since BSForwardGeocoder didn’t support viewport biasing. As it now does, I decided to give it another try.
The app uses an abstract protocol to define how geocoding is done. This makes it really easy to switch implementations. As I replaced Björn’s approach with CLGeocoder, I also changed the protocol to use CLRegion instead of MKCoordinateRegion.
When I re-added Björn’s code, I changed my wrapper class (that implements the protocol and serves as a bridge between the app and the geocoding) so it used a CLRegion as well. As I did, I faced the same behavior using Bjorn’s implementation.
Since, Björn’s code used to work and now didn’t, I realized that the only difference between the old and new implementations was that I CLRegion instead of MKCoordinateRegion. This made me look into the resulting CLRegion and notice that the center lat/long was zero!
How could this be? I verified that the user location was not zero, so how could
the resulting CLRegion have a zero center? Reading the documentation, I found
the answer:
The identifier must not be nil!
So, all this was due to me using a nil identifier, but the app never gave me so much as a silent warning about this. If I pass in nil as an identifier, which I did:
- I don’t get a nil CLRegion in return, but a region with a nil center.
- I don’t crash the application.
- I don’t get any errors whatsoever.
I instead end up with a valid CLRegion, but invalid properties. Talk about silent crashes.