iOS refresh annotations on mapview

Question

I have a mapview where the annotation\'s coordinates are constantly being updated but when I use setCoordinate, the annotation does not move. How do I refresh the annotation

Answer 1

Swift 3.0 version of Nathan's answer (thank you Nathan):

DispatchQueue.main.async {
    mapView.addAnnotation(annotation)
}

Side note, Nathan's answer should have far more upvotes. I actually needed this help with removing an annotation, the same issue exists and is fixed by dispatching the update to the main queue.

Answer 2

Updated (to reflect the solution):

Having your own custom annotations and implementing setCoordinate and/or synthesizing coordinate may cause issues.

Source: http://developer.apple.com/library/ios/#documentation/UserExperience/Conceptual/LocationAwarenessPG/AnnotatingMaps/AnnotatingMaps.html

Previous solution:

You can simply remove all of the annotations and then re-add them.

[mapView removeAnnotations:[mapView.annotations]];

[mapView addAnnotations:(NSArray *)];

or remove them and re-add them one by one:

for (id<MKAnnotation> annotation in mapView.annotations)
{
    [mapView removeAnnotation:annotation];
    // change coordinates etc
    [mapView addAnnotation:annotation]; 
}

Answer 3

Removing all existing annotations, and re-adding the new or updated annotation list will refresh the mapView. Firstly I tried:

mapView.annotations.removeAll()

but received the error:

"Value of type '(MKMapRect) -> Set<AnyHashable>' has no member 'removeAll'"

However this worked:

for annotation in mapView.annotations{
    mapView.removeAnnotation(annotation)
}
// .. code to add the new or updated annotation list

Answer 4

For dark mode purposes I needed to refresh the views of annotations. I had to call also the delegate method to recreate the view of the annotations.

- (void)traitCollectionDidChange:(UITraitCollection *)previousTraitCollection {
    [super traitCollectionDidChange:previousTraitCollection];
    if (@available(iOS 13.0, *)) {
        if ([self.traitCollection hasDifferentColorAppearanceComparedToTraitCollection:previousTraitCollection]) {
            for (id<MKAnnotation> annotation in self.mapView.annotations) {
                [self.mapView removeAnnotation:annotation];
                [self.mapView addAnnotation:annotation];
                [self mapView:self.mapView viewForAnnotation:annotation];
            }
        }
    }
}

Answer 5

Just Add

mapView.reloadStyle(self)

Answer 6

Dispatch the add annotation to the main thread rather then attempt to modify the UI on a background thread

dispatch_async(dispatch_get_main_queue()) {
    self.mapView.addAnnotation(annotation)
}