An abstract adapter class for receiving drop target events. The methods in this class are empty. This class exists only as a convenience for creating listener objects.
Extend this class to create a
DropTargetEvent listener and override the methods for the events of interest. (If you implement the
DropTargetListener interface, you have to define all of the methods in it. This abstract class defines a null implementation for every method except
drop(DropTargetDropEvent), so you only have to define methods for events you care about.) You must provide an implementation for at least
drop(DropTargetDropEvent). This method cannot have a null implementation because its specification requires that you either accept or reject the drop, and, if accepted, indicate whether the drop was successful.
Create a listener object using the extended class and then register it with a
DropTarget. When the drag enters, moves over, or exits the operable part of the drop site for that
DropTarget, when the drop action changes, and when the drop occurs, the relevant method in the listener object is invoked, and the
DropTargetEvent is passed to it.
The operable part of the drop site for the
DropTarget is the part of the associated
Component's geometry that is not obscured by an overlapping top-level window or by another
Component higher in the Z-order that has an associated active
During the drag, the data associated with the current drag operation can be retrieved by calling
DropTargetDragEvent instances passed to the listener's methods.
getTransferable() on the
DropTargetDragEvent instance should only be called within the respective listener's method and all the necessary data should be retrieved from the returned
Transferable before that method returns.