Called when dragged content enters the collection view's bounds rectangle.
- iOS 11.0+
The collection view that is tracking the dragged content.
The drop session object containing information about the type of data being dragged.
The collection view calls this method when dragged content enters its bounds rectangle. The method is not called again until the dragged content exits the collection view's bounds (triggering a call to the
collection method) and enters again.
Use this method to perform any one-time setup associated with tracking dragged content over the collection view.