MKMapView loading all annotation views at once (including those that are outside the current rect)

Posted by jmans on Stack Overflow See other posts from Stack Overflow or by jmans
Published on 2009-08-11T20:30:59Z Indexed on 2010/03/29 9:13 UTC
Read the original article Hit count: 574

Has anyone else run into this problem? Here's the code:

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(WWMapAnnotation *)annotation {



// Only return an Annotation view for the placemarks. Ignore for the current location--the iPhone SDK will place a blue ball there.

NSLog(@"Request for annotation view");

if ([annotation isKindOfClass:[WWMapAnnotation class]]){



    MKPinAnnotationView *browse_map_annot_view = (MKPinAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:@"BrowseMapAnnot"];



    if (!browse_map_annot_view) {
        browse_map_annot_view = [[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"BrowseMapAnnot"] autorelease];
        NSLog(@"Creating new annotation view");
    } else {
        NSLog(@"Recycling annotation view");
        browse_map_annot_view.annotation = annotation;
    }

...

As soon as the view is displayed, I get

2009-08-05 13:12:03.332 xxx[24308:20b] Request for annotation view
2009-08-05 13:12:03.333 xxx[24308:20b] Creating new annotation view
2009-08-05 13:12:03.333 xxx[24308:20b] Request for annotation view
2009-08-05 13:12:03.333 xxx[24308:20b] Creating new annotation view

and on and on, for every annotation (~60) I've added. The map (correctly) only displays the two annotations in the current rect. I am setting the region in viewDidLoad:

if (center_point.latitude == 0) {
    center_point.latitude = 35.785098;
    center_point.longitude = -78.669899;
}

if (map_span.latitudeDelta == 0) {
    map_span.latitudeDelta = .001;
    map_span.longitudeDelta = .001;
}

map_region.center = center_point;
map_region.span = map_span;

NSLog(@"Setting initial map center and region");

[browse_map_view setRegion:map_region animated:NO];

The log entry for the region being set is printed to the console before any annotation views are requested.

The problem here is that since all of the annotations are being requested at once, [mapView dequeueReusableAnnotationViewWithIdentifier] does nothing, since there are unique MKAnnotationViews for every annotation on the map. This is leading to memory problems for me.

One possible issue is that these annotations are clustered in a pretty small space (~1 mile radius). Although the map is zoomed in pretty tight in viewDidLoad (latitude and longitude delta .001), it still loads all of the annotation views at once.

Thanks...

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