I have an MKOverlayView that displays animated radar data as a series of images. The issue I have is that the radar images are chopped into tiles by MapKit. To swap images I have a timer that calls an update function which sets the current image in my overlay and then calls the following
[myRadarOverlayView setNeedsDisplayInMapRect:self.mapView.visibleMapRect];
The overlay updates, but does so one tile at a time so I get a choppy animation. Any ideas about how make all the tiles animate (i.e. swap images) at the exact same time?
I solved this by adding a UIImageView as a subview of the MKOverlayView.
To animate, stop drawing with the normal drawMapRect:zoomScale:inContext: (via an instance variable/property flag) and draw to the UIImageView instead (to the animationImages property), then use startAnimating.
You can handle panning and zooming by reinitializing the UIImageView in response to mapView:regionDidChangeAnimated:.
Sample code how to animate a circle:
http://yickhong-ios.blogspot.com/2012/04/animated-circle-on-mkmapview.html
Is there a callback when all the tiles have finished loading? If so, you could go with double buffering, and update the view offscreen, and then switch it in.
来源：https://stackoverflow.com/questions/4182305/animating-an-mkoverlayview