Overlay on MapView animated - ios

Question

I add an overlay (array of multiple coordinates) and draw a path.
It works perfectly, but I would like (if it's possible), to draw the path with an animation (coordinate by coordinate, or fade in, etc.)
My app is only on iOS 7 or later.
Here my methods:
- (void)drawPathWithAnnotations:(NSArray*)annotations
{
CLLocationCoordinate2D array[[annotations count]];
for (CLLocation *loc in annotations)
{
array[[annotations indexOfObject:loc]] = CLLocationCoordinate2DMake(loc.coordinate.latitude, loc.coordinate.longitude);
}
self.routeLine = [MKPolyline polylineWithCoordinates:array count:[annotations count]];
[self.mapview addOverlay:self.routeLine];
}
- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id<MKOverlay>)overlay
{
if(overlay == self.routeLine){
MKPolylineRenderer* lineView = [[MKPolylineRenderer alloc] initWithPolyline:self.routeLine];
lineView.strokeColor = UIColorFromRGB(kAppTintColor);
lineView.lineWidth = 3;
return lineView;
}
return nil;
}
- (void)mapView:(MKMapView *)mapView didAddOverlayRenderers:(NSArray *)renderers
{
// Animation here ?
}
Thank you, any suggestions or ideas are appreciated! :)

Answer 1

I was looking for an answer to your question and didn't find an accepted one so here is my solution. You were right to assume didAddOverlayRenderers is where you put your animations. Here's an example of how to animate a 'fade' for an overlay:
- (void)mapView:(MKMapView *)mapView didAddOverlayRenderers:(NSArray *)renderers
{
// Iterate through all overlayRenderers
for (MKOverlayRenderer *overlayRenderer in renderers)
{
// MKPolylineRenderer
// Animate a 'fade'
if ([overlayRenderer isKindOfClass:[MKPolylineRenderer class]])
{
// Get MKPolylineRenderer
MKPolylineRenderer *polylineRenderer = (MKPolylineRenderer *)overlayRenderer;
// Let's manually set alpha to 0
polylineRenderer.alpha = 0.0f;
// Animate it back to 1
dispatch_async(dispatch_get_main_queue(), ^{
[UIView animateWithDuration:0.4 animations:^{
polylineRenderer.alpha = 1.0f
}];
});
}
}
}