Refresh MKAnnotationView on a MKMapView
Solution 1
I haven't tried it myself, but it might work:
Get a view for annotation using MKMapView - (MKAnnotationView *)viewForAnnotation:(id <MKAnnotation>)annotation
method and set new image to it.
Edit: Tried to do that myself and this approach worked fine for me:
// Function where you got new image and want to set it to annotation view
for (MyAnnotationType* myAnnot in myAnnotationContainer){
MKAnnotationView* aView = [mapView viewForAnnotation: myAnnot];
aView.image = [UIImage imageNamed:@"myJustDownloadedImage.png"];
}
After calling this method all annotations images were updated.
Solution 2
I found only one reliable way to update annotation, others methods didn't work for me: just removing and adding annotation again:
id <MKAnnotation> annotation;
// ...
[mapView removeAnnotation:annotation];
[mapView addAnnotation:annotation];
This code will make -[mapView:viewForAnnotation:] to be called again and so your annotation view will be created again (or maybe reused if you use dequeueReusableAnnotationViewWithIdentifier) with correct data.
Solution 3
This is the only way I've found to force redraw of MKAnnotationViews:
// force update of map view (otherwise annotation views won't redraw)
CLLocationCoordinate2D center = mapView.centerCoordinate;
mapView.centerCoordinate = center;
Seems useless, but it works.
Solution 4
This worked for me
#import "EGOImageView.h"
- (MKAnnotationView *)mapView:(MKMapView *)theMapView viewForAnnotation:(id <MKAnnotation>)annotation
{
//ENTER_METHOD;
if([annotation isKindOfClass:[MKUserLocation class]]) return nil;
MKPinAnnotationView *annView;
static NSString *reuseIdentifier = @"reusedAnnView";
annView = [[MKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:reuseIdentifier];
annView.canShowCallout = YES;
annView.calloutOffset = CGPointMake(-5.0f, 0.0f);
annView.opaque = NO;
annView.image = [[UIImage imageNamed:@"tempImage.png"] retain];
YourModel *p = annotation; // make this conform to <MKAnnotation>
EGOImageView *egoIV = [[EGOImageView alloc] initWithPlaceholderImage:[UIImage imageNamed:@"tempImage.png"]];
[egoIV setDelegate:self];
egoIV.imageURL = [NSURL URLWithString:p.theUrlToDownloadFrom];
[annView addSubview:egoIV];
[egoIV release];
return [annView autorelease];
}
cocoapriest
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Updated on January 24, 2021Comments
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cocoapriest over 3 years
I'd like to a-synchronically load images for my custom MKAnnotationView; I'm already using the EGOImageView-framework (it goes very well with UITableViews), but I fail to make it work on MKMapView. Images seem to be loaded, but I cannot refresh them on the map -
[myMap setNeedsDisplay]
does nothing.