Objective-C - Search for streets based on user-entered query

Question

I want to allow the users to search for a street name and have the results displayed in a UITableView. For the moment the region is not important, it can be from any region.

I could not find any relevant example in my searches and I don't know if I should use CLLocation or MKLocalSearch.

Based on docs, I should use MKLocalSearch:

Although local search and geocoding are similar, they support different use cases. Use geocoding when you want to convert between map coordinates and a structured address, such as an Address Book address. Use local search when you want to find a set of locations that match the user’s input.

But I have tried both methods and it gives me only 1 result (even-though there is an NSArray returned.

This is the CLGeocoder approach:

CLGeocoder *geocoding = [[CLGeocoder alloc] init];
[geocoding geocodeAddressString:theTextField.text completionHandler:^(NSArray *placemarks, NSError *error) {
    if (error) {
        NSLog(@"%@", error);
    } else {
        NSLog(@"%i", [placemarks count]);
        for(CLPlacemark *myStr in placemarks) {
            NSLog(@"%@", myStr);
    }
    }
}];

And this is my MKLocalSearch try:

MKLocalSearchRequest *request = [[MKLocalSearchRequest alloc] init];
request.naturalLanguageQuery = theTextField.text;
request.region = self.region;

localSearch = [[MKLocalSearch alloc] initWithRequest:request];

[localSearch startWithCompletionHandler:^(MKLocalSearchResponse *response, NSError *error){

    if (error != nil) {
        [[[UIAlertView alloc] initWithTitle:NSLocalizedString(@"Map Error",nil)
                                    message:[error localizedDescription]
                                   delegate:nil
                          cancelButtonTitle:NSLocalizedString(@"OK",nil) otherButtonTitles:nil] show];
        return;
    }

    if ([response.mapItems count] == 0) {
        [[[UIAlertView alloc] initWithTitle:NSLocalizedString(@"No Results",nil)
                                    message:nil
                                   delegate:nil
                          cancelButtonTitle:NSLocalizedString(@"OK",nil) otherButtonTitles:nil] show];
        return;
    }
    self.streets = response;
    [self.streetsTableView reloadData];
}];

MKLocalSearch seems to return more than 1 response in some cases, but these are related to places not street names searches.

Thanks in advance.

Carvey

did you try setting region to nil? or can you share more details on your self.region? – Jingo

I have a MapView and I am using MapView.region as self.region – Carvey

from my experience MKLocalSearch is very primitive. Would you be opposed to using Google Places API for any reason? – Warthman

google has a more useful api, MKLocalSearch is for a simple tasks only – Commendam

Answer 1

This is the closest I could get. This involves using google places API Web Service.

Note: You could probably use their Google Maps API, etc. I am sure there are other ways to get this information from the various Google APIs.

 NSURL *googlePlacesURL = [NSURL URLWithString:[NSString stringWithFormat:@"https://maps.googleapis.com/maps/api/place/autocomplete/json?input=%@&location=%f,%f&sensor=true&key=API_KEY", formattedSearchText, location.coordinate.latitude,
                                                   location.coordinate.longitude]];

The response is a JSON object. Convert it to a dictionary.

 NSDictionary *response = [NSJSONSerialization JSONObjectWithData:_googlePlacesResponse
                                                                    options:NSJSONReadingMutableContainers error:&error];

if([[response objectForKey:@"status"] isEqualToString:@"OK"])
{
    NSArray *predictions = [response objectForKey:@"predictions"];
    for(NSDictionary *prediction in predictions)
    {
        NSArray *addressTypes = [prediction objectForKey:@"types"];
        if([addressTypes containsObject:@"route"])
        {
            //This search result contains a street name. 
            //Now get the street name.
            NSArray *terms = [prediction objectForKey:@"terms"];
            NSDictionary *streetNameKeyValuePair = [terms objectAtIndex:0];
            NSLog(@"%@",[streetNameKeyValuePair objectForKey@"value"]);
        }
    }
}

The possible types seem to be

Route -> Street name

Locality -> City/location name

Political -> State, etc

Geocode -> lat/long available

You could populate the table view with those predictions that ONLY contain route as an address type. This could work.

Warthman

Yep, that's the way. I have done the same, before reading your answer :). This one helped me: https://mcmap.net/q/1469556/-mklocalsearch-not-finding-obvious-results – Carvey

Answer 2

CLGeocoder simply returns address format. Slap this in your code and play with the contents of mapitems

MKLocalSearchRequest *request = [MKLocalSearchRequest new];
request.naturalLanguageQuery = @"Pizza";
request.region = MKCoordinateRegionMake(location.coordinate, MKCoordinateSpanMake(.01, .01));
MKLocalSearch *search = [[MKLocalSearch alloc]initWithRequest:request];
[search startWithCompletionHandler:^(MKLocalSearchResponse *response, NSError *error) {
    NSArray *mapItems = response.mapItems;
    for (MKMapItem *mapItem in mapItems) {
        MKPointAnnotation *point = [MKPointAnnotation new];
        point.coordinate = mapItem.placemark.coordinate;`
    }
}];

Hag

Answer 3

The array returned contains mapItems, you can iterate over the array to pull out all the mapItems like this:

myMatchingItems = [[NSMutableArray alloc] init];
for (MKMapItem *item in response.mapItems){
                    [myMatchingItems addObject:item];
    }

Each mapItem.placemark.thoroughfare contains the Street of the location that was found.

Investigation