Gets the item and relative place in the collection that an object is being dropped over.
drop-object-collection-item drop-object => item , placement
(setf (drop-object-collection-item drop-object ) (values new-item new-placement ))
A drop-object , as passed to the drop-callback .
An item of a collection.
One of
:above
,
:item
or
:below
.
The function
drop-object-collection-item
returns the item and place relative to that item within the collection that the object
drop-object
is being dropped over. This information is only meaningful when the pane is an instance of list-panel or tree-view.
The returned value placement indicates whether the user is dropping above, on or below the item.
There is also a setf expander that can be called with these two values within the
:drag
stage of the operation, to adjust where the user will be allowed to drop the object.
drop-object-collection-item
should only be called within a
drop-callback
. It is not supported on X11/Motif. See simple-pane for information about drop callbacks.
For an example illustrating the use of drag and drop in a choice, see
examples/capi/choices/drag-and-drop.lisp