EventListener
DropTarget
, DropTargetAdapter
public interface DropTargetListener extends EventListener
DropTargetListener
interface is the callback interface used by the DropTarget
class to provide notification of DnD operations that involve the subject DropTarget
. Methods of this interface may be implemented to provide "drag under" visual feedback to the user throughout the Drag and Drop operation. Create a listener object by implementing the interface 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 DropTarget
.
During the drag, the data associated with the current drag operation can be retrieved by calling getTransferable()
on DropTargetDragEvent
instances passed to the listener's methods.
Note that 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.
Modifier and Type | Method | Description |
---|---|---|
void |
dragEnter |
Called while a drag operation is ongoing, when the mouse pointer enters the operable part of the drop site for the DropTarget registered with this listener. |
void |
dragExit |
Called while a drag operation is ongoing, when the mouse pointer has exited the operable part of the drop site for the DropTarget registered with this listener. |
void |
dragOver |
Called when a drag operation is ongoing, while the mouse pointer is still over the operable part of the drop site for the DropTarget registered with this listener. |
void |
drop |
Called when the drag operation has terminated with a drop on the operable part of the drop site for the DropTarget registered with this listener. |
void |
dropActionChanged |
Called if the user has modified the current drop gesture. |
void dragEnter(DropTargetDragEvent dtde)
DropTarget
registered with this listener.dtde
- the DropTargetDragEvent
void dragOver(DropTargetDragEvent dtde)
DropTarget
registered with this listener.dtde
- the DropTargetDragEvent
void dropActionChanged(DropTargetDragEvent dtde)
dtde
- the DropTargetDragEvent
void dragExit(DropTargetEvent dte)
DropTarget
registered with this listener.dte
- the DropTargetEvent
void drop(DropTargetDropEvent dtde)
DropTarget
registered with this listener. This method is responsible for undertaking the transfer of the data associated with the gesture. The DropTargetDropEvent
provides a means to obtain a Transferable
object that represents the data object(s) to be transferred.
From this method, the DropTargetListener
shall accept or reject the drop via the acceptDrop(int dropAction) or rejectDrop() methods of the DropTargetDropEvent
parameter.
Subsequent to acceptDrop(), but not before, DropTargetDropEvent
's getTransferable() method may be invoked, and data transfer may be performed via the returned Transferable
's getTransferData() method.
At the completion of a drop, an implementation of this method is required to signal the success/failure of the drop by passing an appropriate boolean
to the DropTargetDropEvent
's dropComplete(boolean success) method.
Note: The data transfer should be completed before the call to the DropTargetDropEvent
's dropComplete(boolean success) method. After that, a call to the getTransferData() method of the Transferable
returned by DropTargetDropEvent.getTransferable()
is guaranteed to succeed only if the data transfer is local; that is, only if DropTargetDropEvent.isLocalTransfer()
returns true
. Otherwise, the behavior of the call is implementation-dependent.
dtde
- the DropTargetDropEvent
© 1993, 2023, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
https://docs.oracle.com/en/java/javase/21/docs/api/java.desktop/java/awt/dnd/DropTargetListener.html