Check if mapView already contains an annotation - objective-c

Question

I have a method of adding secondary nearby annotations (ann2) when I tap on another annotation (ann1). But when I deselect and re-select the exact same annotation (ann1) the ann2 re-creates it self and is getting added again. Is there a way to check if the annotation already exists on the map and if yes then do nothing otherwise add the new annotation. I have already checked this: Restrict Duplicate Annotation on MapView but it did not help me.. Any advice is appreciated. This is what I have so far:
fixedLocationsPin *pin = [[fixedLocationsPin alloc] init];
pin.title = [NSString stringWithFormat:#"%#",nearestPlace];
pin.subtitle = pinSubtitle;
pin.coordinate = CLLocationCoordinate2DMake(newObject.lat, newObject.lon);
for (fixedLocationsPin *pins in mapView.annotations) {
if (MKMapRectContainsPoint(mapView.visibleMapRect, MKMapPointForCoordinate (pins.coordinate))) {
NSLog(#"already in map");
}else{
[mapView addAnnotation:pin];
}
In this case I get the log already on map but I also get the drop animation of the annotation adding to the map. Any ideas?
Thank you in advance..

Answer 1

Your for loop isn't checking if the annotation is on the screen, it is checking if the coordinates of the pin are currently within the visible area. Even if it was checking if the pin object was already in the mapView.annotations it would never be true, because you've only just created pin a few lines earlier, it can't possibly be the same object as on in the mapView.annotations. It might though have the same coordinates and title, and that's what you need to check:
bool found = false;
for (fixedLocationsPin *existingPin in mapView.annotations)
{
if (([existingPin.title isEqualToString:pin.title] &&
(existingPin.coordinate.latitude == pin.coordinate.latitude)
(existingPin.coordinate.longitude == pin.coordinate.longitude))
{
NSLog(#"already in map");
found = true;
break;
}
}
if (!found)
{
[mapView addAnnotation:pin];
}

Answer 2

Annotations array exist in map object so you just have to check
if ( yourmap.annotations.count==0)
{
NSLog(#"no annotations");
}

Answer 3

NSNumber *latCord = [row valueForKey:#"latitude"];
NSNumber *longCord = [row valueForKey:#"longitude"];
NSString *title = [row valueForKey:#"name"];
CLLocationCoordinate2D coord;
coord.latitude = latCord.doubleValue;
coord.longitude = longCord.doubleValue;
MapAnnotation *annotation = [[MapAnnotation alloc]initWithCoordinate:coord withTitle:title];
if([mkMapView.annotations containsObject:annotation]==YES){
//add codes here if the map contains the annotation.
}else {
//add codes here if the annotation does not exist in the map.
}

Answer 4

if (sampleMapView.annotations.count > 0) {
sampleMapView.removeAnnotation(detailMapView.annotations.last!)
}

Answer 5

Following my comment on Craig's answer, I think the solution could look like something like this :
import MapKit
extension MKMapView {
func containsAnnotation(annotation: MKAnnotation) -> Bool {
if let existingAnnotations = self.annotations as? [MKAnnotation] {
for existingAnnotation in existingAnnotations {
if existingAnnotation.title == annotation.title
&& existingAnnotation.coordinate.latitude == annotation.coordinate.latitude
&& existingAnnotation.coordinate.longitude == annotation.coordinate.longitude {
return true
}
}
}
return false
}
}
This code allows you to check if a mapView contains a given annotation. Use this in a "for" loop on all your annotations:
for annotation in annotations {
if mapView.containsAnnotation(annotation) {
// do nothing
} else {
mapView.addAnnotation(annotation)
}
PS: this works well if you need to add new annotations to a mapView. But if you need also to remove entries, you may have to do the opposite: check that each existing annotation exists in the new array of annotations ; if not, remove it.
Or you could remove everything and add everything again (but then you will have the change animated ...)