问题
I've been trying to add an MKOverlay to a map with animation. I'm trying to make it fade in when it's added and fade out when it's removed. Could this be done by created a custom overlay class or overlay view class?
回答1:
On iOS 7 you could achieve this even with the new MKOverlayRenderer. It has an alpha property which you could animate by setting up a timer to repeatedly change its value and call setNeedsDisplayInMapRect:zoomScale:.
回答2:
This is trickier in iOS 7 and above since the overlays aren't represented with views anymore, but rather drawn with renderers (either using the stock ones or rendering yourself in a provided CGContext in the delegate).
Whatever you do here will be rendered on a tiled basis, which could lead to differences in appearance across you map view.
You can read more on this here: https://github.com/mapbox/mbxmapkit/issues/39
来源：https://stackoverflow.com/questions/22696949/objective-c-add-mkoverlay-to-map-view-animated-fade-in