I want to use MKLocalSearch
for searching in a Map. This functionality is available in iOS 6.1+. Does anybody know how to use this or can anybody give an example of how to use an MKLocalSearch
?
The API for MKLocalSearch
is fairly easy to understand. At its most basic, you
alloc-init
an MKLocalSearchRequest
naturalLanguageQuery
to some search termMKLocalSearch
objectMKMapItem
objects in the response
Search for Cafes:
// Create a search request with a string
MKLocalSearchRequest *searchRequest = [[MKLocalSearchRequest alloc] init];
[searchRequest setNaturalLanguageQuery:@"Cafe"];
// Create the local search to perform the search
MKLocalSearch *localSearch = [[MKLocalSearch alloc] initWithRequest:searchRequest];
[localSearch startWithCompletionHandler:^(MKLocalSearchResponse *response, NSError *error) {
if (!error) {
for (MKMapItem *mapItem in [response mapItems]) {
NSLog(@"Name: %@, Placemark title: %@", [mapItem name], [[mapItem placemark] title]);
}
} else {
NSLog(@"Search Request Error: %@", [error localizedDescription]);
}
}];
You can specify a region for the search like this:
// Search for Cafes in Paris
MKLocalSearchRequest *searchRequest = [[MKLocalSearchRequest alloc] init];
[searchRequest setNaturalLanguageQuery:@"Cafe"];
CLLocationCoordinate2D parisCenter = CLLocationCoordinate2DMake(48.8566667, 2.3509871);
MKCoordinateRegion parisRegion = MKCoordinateRegionMakeWithDistance(parisCenter, 15000, 15000);
[searchRequest setRegion:parisRegion];
You can also take the region from an MKMapView
that the user has zoomed into. This will give better results:
[searchRequest setRegion:self.mapView.region];
The response object, an MKLocalSearchResponse
, contains an array of MKMapItem
objects (mapItems
) and an MKCoordinateRegion
called boundingRegion
, which is a region that contains all the results. You can use it to set a map view to show all results:
[self.mapView setRegion:response.boundingRegion];
The array of MKMapItem
objects can't be placed on a map (they're used for sending to the Maps app) but each contains a placemark
property which can be added to a map:
[localSearch startWithCompletionHandler:^(MKLocalSearchResponse *response, NSError *error) {
if (!error) {
for (MKMapItem *mapItem in [response mapItems]) {
NSLog(@"Name: %@, MKAnnotation title: %@", [mapItem name], [[mapItem placemark] title]);
NSLog(@"Coordinate: %f %f", [[mapItem placemark] coordinate].latitude, [[mapItem placemark] coordinate].longitude);
// Should use a weak copy of self
[self.mapView addAnnotation:[mapItem placemark]];
}
} else {
NSLog(@"Search Request Error: %@", [error localizedDescription]);
}
}];
Search for Dublin places a pin on the map view and logs:
Name: Dublin, Co. Dublin, MKAnnotation title: Dublin, Co. Dublin, Ireland
Coordinate: 53.344104 -6.267494
There are a load of extra details in the returned objects, especially if you search for businesses. Here are a few:
[localSearch startWithCompletionHandler:^(MKLocalSearchResponse *response, NSError *error) {
if (!error) {
NSLog(@"Results: %@", [response mapItems]);
MKMapItem *mapItem = [[response mapItems] objectAtIndex:0];
NSLog(@"Name:%@ Phone:%@ URL:%@", [mapItem name], [mapItem phoneNumber], [mapItem url]);
NSLog(@"Placemark: %@", [mapItem placemark]);
MKPlacemark *placemark = [mapItem placemark];
NSLog(@"Placemark Address: %@", [placemark addressDictionary]);
MKCoordinateRegion boundingRegion = [response boundingRegion];
NSLog(@"Bounds: %f %f", boundingRegion.span.latitudeDelta, boundingRegion.span.longitudeDelta);
}