collectionView performDropWithCoordinator:(id<UICollectionViewDropCoordinator>)coordinator;UIDragItem不幸的是,当我打印出item时,Xcode一直告诉我Property 'sourceIndexPath' not found on object of type 'UIDragItem *',我清楚地看到该属性是可用的
attributes to print
}}func dragItemFor(indexPath: IndexPath) -> [UIDragItem("pre drag vc: ",attr.key, attr.value)// prints the font let dragItem = UIDragItem