Support drag-and-drop (iOS 11)

[friedbunny]

One of the primary new features in iOS 11 is inter-app drag and drop. We should make any necessary changes so that our map view supports drag and drop well out of the box, without external dependencies or network calls.

Considerations

• Rasterization — the snapshot workaround in Add map snapshot API #1701 may be good enough, as users will be dragging from already-rendered foreground maps.
• Attribution — Hide the ℹ️ attribution button if map isn't interactive #3804 would replace the ℹ️ button with text when a map is not interactive.

Marking this as “MapKit parity” on assumption, but I actually have no idea the extent to which they support drag and drop.

Resources

• https://www.mapbox.com/blog/mapbox-drag-and-drop-ios11/
• WWDC ’17: Data Delivery with Drag and Drop
• UIKit docs: Adopting drag and drop in a custom view

/cc @jmkiley @captainbarbosa @mapbox/ios

[jmkiley]

Agreed! This is something I've been exploring, and can see a lot of potential uses. I think that the first step is to look into how/if we can make MGLMapViews conform to NSItemProviderWriting.

Attribution and MAUs are another challenge. We could adopt a similar approach as what was taken in @captainbarbosa's blog post and switch to static attribution once the drag/drop begins. If the map remains interactive, we could look into adapting the attribution button. Switching to text attribution once a drag interaction is detected is likely the best approach, since without an interactive map, telemetry opt-in/out isn't necessary.

[stale]

This issue has been automatically detected as stale because it has not had recent activity and will be archived. Thank you for your contributions.

[stale]

This issue has been automatically detected as stale because it has not had recent activity and will be archived. Thank you for your contributions.