Interface DropTargetListener
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- All Superinterfaces:
- EventListener
- All Known Implementing Classes:
- DropTarget, DropTargetAdapter
public interface DropTargetListener extends EventListener
TheDropTargetListenerinterface is the callback interface used by theDropTargetclass to provide notification of DnD operations that involve the subjectDropTarget. 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 thatDropTarget, when the drop action changes, and when the drop occurs, the relevant method in the listener object is invoked, and theDropTargetEventis passed to it.The operable part of the drop site for the
DropTargetis the part of the associatedComponent's geometry that is not obscured by an overlapping top-level window or by anotherComponenthigher in the Z-order that has an associated activeDropTarget.During the drag, the data associated with the current drag operation can be retrieved by calling
getTransferable()onDropTargetDragEventinstances passed to the listener's methods.Note that
getTransferable()on theDropTargetDragEventinstance should only be called within the respective listener's method and all the necessary data should be retrieved from the returnedTransferablebefore that method returns.- Since:
- 1.2
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method and Description voiddragEnter(DropTargetDragEvent dtde)Called while a drag operation is ongoing, when the mouse pointer enters the operable part of the drop site for theDropTargetregistered with this listener.voiddragExit(DropTargetEvent dte)Called while a drag operation is ongoing, when the mouse pointer has exited the operable part of the drop site for theDropTargetregistered with this listener.voiddragOver(DropTargetDragEvent dtde)Called when a drag operation is ongoing, while the mouse pointer is still over the operable part of the drop site for theDropTargetregistered with this listener.voiddrop(DropTargetDropEvent dtde)Called when the drag operation has terminated with a drop on the operable part of the drop site for theDropTargetregistered with this listener.voiddropActionChanged(DropTargetDragEvent dtde)Called if the user has modified the current drop gesture.
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Method Detail
dragEnter
void dragEnter(DropTargetDragEvent dtde)
Called while a drag operation is ongoing, when the mouse pointer enters the operable part of the drop site for theDropTargetregistered with this listener.- Parameters:
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dtde- theDropTargetDragEvent
dragOver
void dragOver(DropTargetDragEvent dtde)
Called when a drag operation is ongoing, while the mouse pointer is still over the operable part of the drop site for theDropTargetregistered with this listener.- Parameters:
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dtde- theDropTargetDragEvent
dropActionChanged
void dropActionChanged(DropTargetDragEvent dtde)
Called if the user has modified the current drop gesture.- Parameters:
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dtde- theDropTargetDragEvent
dragExit
void dragExit(DropTargetEvent dte)
Called while a drag operation is ongoing, when the mouse pointer has exited the operable part of the drop site for theDropTargetregistered with this listener.- Parameters:
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dte- theDropTargetEvent
drop
void drop(DropTargetDropEvent dtde)
Called when the drag operation has terminated with a drop on the operable part of the drop site for theDropTargetregistered with this listener.This method is responsible for undertaking the transfer of the data associated with the gesture. The
DropTargetDropEventprovides a means to obtain aTransferableobject that represents the data object(s) to be transfered.From this method, the
DropTargetListenershall accept or reject the drop via the acceptDrop(int dropAction) or rejectDrop() methods of theDropTargetDropEventparameter.Subsequent to acceptDrop(), but not before,
DropTargetDropEvent's getTransferable() method may be invoked, and data transfer may be performed via the returnedTransferable'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
booleanto theDropTargetDropEvent'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 theTransferablereturned byDropTargetDropEvent.getTransferable()is guaranteed to succeed only if the data transfer is local; that is, only ifDropTargetDropEvent.isLocalTransfer()returnstrue. Otherwise, the behavior of the call is implementation-dependent.- Parameters:
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dtde- theDropTargetDropEvent
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