public interface UICollectionViewDragDelegate

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`default UIDragPreviewParameters`	`collectionViewDragPreviewParametersForItemAtIndexPath(UICollectionView collectionView, NSIndexPath indexPath)`	Allows customization of the preview used for the item being lifted from or cancelling back to the collection view.
`default boolean`	`collectionViewDragSessionAllowsMoveOperation(UICollectionView collectionView, UIDragSession session)`	Controls whether move operations (see UICollectionViewDropProposal.operation) are allowed for the drag session.
`default void`	`collectionViewDragSessionDidEnd(UICollectionView collectionView, UIDragSession session)`	Called to signal the end of the drag session.
`default boolean`	`collectionViewDragSessionIsRestrictedToDraggingApplication(UICollectionView collectionView, UIDragSession session)`	Controls whether the drag session is restricted to the source application.
`default void`	`collectionViewDragSessionWillBegin(UICollectionView collectionView, UIDragSession session)`	Called after the lift animation has completed to signal the start of a drag session.
`default NSArray<? extends UIDragItem>`	`collectionViewItemsForAddingToDragSessionAtIndexPathPoint(UICollectionView collectionView, UIDragSession session, NSIndexPath indexPath, CGPoint point)`	Called to request items to add to an existing drag session in response to the add item gesture.
`NSArray<? extends UIDragItem>`	`collectionViewItemsForBeginningDragSessionAtIndexPath(UICollectionView collectionView, UIDragSession session, NSIndexPath indexPath)`	Provide items to begin a drag associated with a given indexPath.

Method Detail

collectionViewDragPreviewParametersForItemAtIndexPath

default UIDragPreviewParameters collectionViewDragPreviewParametersForItemAtIndexPath(UICollectionView collectionView,
                                                                                      NSIndexPath indexPath)

Allows customization of the preview used for the item being lifted from or cancelling back to the collection view. If not implemented or if nil is returned, the entire cell will be used for the preview.

collectionViewDragSessionAllowsMoveOperation

default boolean collectionViewDragSessionAllowsMoveOperation(UICollectionView collectionView,
                                                             UIDragSession session)

Controls whether move operations (see UICollectionViewDropProposal.operation) are allowed for the drag session. If not implemented this will default to YES.

collectionViewDragSessionDidEnd

default void collectionViewDragSessionDidEnd(UICollectionView collectionView,
                                             UIDragSession session)

Called to signal the end of the drag session.

collectionViewDragSessionIsRestrictedToDraggingApplication

default boolean collectionViewDragSessionIsRestrictedToDraggingApplication(UICollectionView collectionView,
                                                                           UIDragSession session)

Controls whether the drag session is restricted to the source application. If YES the current drag session will not be permitted to drop into another application. If not implemented this will default to NO.

collectionViewDragSessionWillBegin
```
default void collectionViewDragSessionWillBegin(UICollectionView collectionView,
                                                UIDragSession session)
```
Called after the lift animation has completed to signal the start of a drag session. This call will always be balanced with a corresponding call to -collectionView:dragSessionDidEnd:

collectionViewItemsForAddingToDragSessionAtIndexPathPoint

default NSArray<? extends UIDragItem> collectionViewItemsForAddingToDragSessionAtIndexPathPoint(UICollectionView collectionView,
                                                                                                UIDragSession session,
                                                                                                NSIndexPath indexPath,
                                                                                                CGPoint point)

Called to request items to add to an existing drag session in response to the add item gesture. You can use the provided point (in the collection view's coordinate space) to do additional hit testing if desired. If not implemented, or if an empty array is returned, no items will be added to the drag and the gesture will be handled normally.

collectionViewItemsForBeginningDragSessionAtIndexPath

NSArray<? extends UIDragItem> collectionViewItemsForBeginningDragSessionAtIndexPath(UICollectionView collectionView,
                                                                                    UIDragSession session,
                                                                                    NSIndexPath indexPath)

Provide items to begin a drag associated with a given indexPath. If an empty array is returned a drag session will not begin.

Interface UICollectionViewDragDelegate