adding multiple circles around a pin in iOS - ios

Question

How can I add and display multiple circles in different colors inside a map (MKMapView)? I figured out how to add one circle, but can't figure out how to add multiple circles in various sizes and colors ... any help would be appreciated!

Answer 1

Here's some code I use to draw two concentric circles at a given location on the map. The outer one is gray, and the inner one is white. (in my example "range" is the circle radius) Both have some transparency:
- (void)drawRangeRings: (CLLocationCoordinate2D) where {
// first, I clear out any previous overlays:
[mapView removeOverlays: [mapView overlays]];
float range = [self.rangeCalc currentRange] / MILES_PER_METER;
MKCircle* outerCircle = [MKCircle circleWithCenterCoordinate: where radius: range];
outerCircle.title = #"Stretch Range";
MKCircle* innerCircle = [MKCircle circleWithCenterCoordinate: where radius: (range / 1.425f)];
innerCircle.title = #"Safe Range";
[mapView addOverlay: outerCircle];
[mapView addOverlay: innerCircle];
}
Then, make sure your class implements the MKMapViewDelegate protocol, and define how your overlays look in the following method:
- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id <MKOverlay>)overlay {
MKCircle* circle = overlay;
MKCircleView* circleView = [[MKCircleView alloc] initWithCircle: circle];
if ([circle.title compare: #"Safe Range"] == NSOrderedSame) {
circleView.fillColor = [UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:0.25];
circleView.strokeColor = [UIColor whiteColor];
} else {
circleView.fillColor = [UIColor colorWithRed:0.5 green:0.5 blue:0.5 alpha:0.25];
circleView.strokeColor = [UIColor grayColor];
}
circleView.lineWidth = 2.0;
return circleView;
}
And, of course, don't forget to set the delegate on your MKMapView object, or the above method will never get called:
mapView.delegate = self;