Refreshing a MKMapView when the user location is updated or using default values
- by koichirose
I'm trying to refresh my map view and load new data from the server when the device acquires the user location.
Here's what I'm doing:
- (void)viewDidLoad {
CGRect bounds = self.view.bounds;
mapView = [[MKMapView alloc] initWithFrame:bounds];
mapView.showsUserLocation=YES;
mapView.delegate=self;
[self.view insertSubview:mapView atIndex:0];
[self refreshMap];
}
- (void)mapView:(MKMapView *)theMapView didUpdateUserLocation:(MKUserLocation *)userLocation
{
//this is to avoid frequent updates, I just need one position and don't need to continuously track the user's location
if (userLocation.location.horizontalAccuracy > self.myUserLocation.location.horizontalAccuracy) {
self.myUserLocation = userLocation;
CLLocationCoordinate2D centerCoord = { userLocation.location.coordinate.latitude, userLocation.location.coordinate.longitude };
[theMapView setCenterCoordinate:centerCoord zoomLevel:10 animated:YES];
[self refreshMap];
}
}
- (void)refreshMap {
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];
[self.mapView removeAnnotations:self.mapView.annotations];
//default position
NSString *lat = @"45.464161";
NSString *lon = @"9.190336";
if (self.myUserLocation != nil) {
lat = [[NSNumber numberWithDouble:myUserLocation.coordinate.latitude] stringValue];
lon = [[NSNumber numberWithDouble:myUserLocation.coordinate.longitude] stringValue];
}
NSString *url = [[NSString alloc] initWithFormat:@"http://myserver/geo_search.json?lat=%@&lon=%@", lat, lon];
NSURLRequest *theRequest=[NSURLRequest requestWithURL:[NSURL URLWithString:url]
cachePolicy:NSURLRequestUseProtocolCachePolicy
timeoutInterval:60.0];
[[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
[url release];
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
}
I also have a - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data, to create and add the annotations.
Here's what happens:
sometimes I get the location after a while, so I already loaded data close to the default location.
Then I get the location and it should remove the old annotations and add the new ones, instead I keep seeing the old annotations and the new ones are added anyway (let's say I receive 10 annotations each time, so it means that I have 20 on my map when I should have 10).
What am I doing wrong?
