Instance Method

collectionView:canDragItemsAtIndexPaths:withEvent:

Returns a Boolean indicating whether a drag operation involving the specified items can begin.

Declaration

- (BOOL)collectionView:(NSCollectionView *)collectionView canDragItemsAtIndexPaths:(NSSet<NSIndexPath *> *)indexPaths withEvent:(NSEvent *)event;

Parameters

collectionView

The collection view making the request.

indexPaths

The index paths of the items about to be dragged.

event

The mouse-down event that began the drag operation.

Return Value

YES if the drag operation can begin or NO if it cannot.

Discussion

If you do not implement this method and your collection view has only one section, the collection view calls the legacy collectionView:canDragItemsAtIndexes:withEvent: method. If you do not implement either method, the collection view assumes a return value of YES.

See Also

Drag and Drop Support

Supporting Collection View Drag and Drop Through File Promises

Share data between macOS apps during drag and drop by using an item provider.

- collectionView:pasteboardWriterForItemAtIndexPath:

Provides the pasteboard writer for the item at the specified index path.

- collectionView:writeItemsAtIndexPaths:toPasteboard:

Places the data for the drag operation on the pasteboard.

Deprecated
- collectionView:namesOfPromisedFilesDroppedAtDestination:forDraggedItemsAtIndexPaths:

Returns the names of the promised files that you created for a drag operation.

Deprecated
- collectionView:draggingImageForItemsAtIndexPaths:withEvent:offset:

Creates and returns a drag image to represent the specified items during a drag.

- collectionView:draggingSession:willBeginAtPoint:forItemsAtIndexPaths:

Notifies your delegate that a drag session is about to begin.

- collectionView:draggingSession:endedAtPoint:dragOperation:

Notifies your delegate that a drag session ended.

- collectionView:updateDraggingItemsForDrag:

Asks your delegate to update the dragging items during a drag operation.

- collectionView:validateDrop:proposedIndexPath:dropOperation:

Validates whether a drop operation is possible at the specified location.

- collectionView:acceptDrop:indexPath:dropOperation:

Incorporates the dropped content into the collection view.