JavaTM 2 Platform
Std. Ed. v1.3

Package java.awt.dnd

Drag and Drop is a direct manipulation gesture found in many Graphical User Interface systems that provides a mechanism to transfer information between two entities logically associated with presentation elements in the GUI.


Interface Summary
Autoscroll During DnD operations it is possible that a user may wish to drop the subject of the operation on a region of a scrollable GUI control that is not currently visible to the user.
DragGestureListener This interface is sourced from a DragGestureRecognizer and is invoked when an object of that (sub)class detects a drag initiating gesture.
DragSourceListener The DragSourceListener defines the event interface for originators of Drag and Drop operations to track the state of the user's gesture, and to provide appropriate "drag over" feedback to the user throughout the Drag and Drop operation.
DropTargetListener The DropTargetListener interface is the callback interface used by the DropTarget class to provide notification of DnD operations that involve the subject DropTarget.

Class Summary
DnDConstants This class contains constant values representing the type of action(s) to be performed by a Drag and Drop operation.
DragGestureEvent A DragGestureEvent is passed to DragGestureListener's dragGestureRecognized() method when a particular DragGestureRecognizer detects that a platform dependent drag initiating gesture has occurred on the Component that it is tracking.
DragGestureRecognizer The DragGestureRecognizer is an abstract base class for the specification of a platform-dependent listener that can be associated with a particular Component in order to identify platform-dependent drag initiating gestures.
DragSource The DragSource is the entity responsible for the initiation of the Drag and Drop operation, and may be used in a number of scenarios: 1 default instance per JVM for the lifetime of that JVM.
DragSourceContext The DragSourceContext class is responsible for managing the initiator side of the Drag and Drop protocol.
DragSourceDragEvent The DragSourceDragEvent is delivered from the DragSourceContextPeer, via the DragSourceContext, to the currently registered DragSourceListener.
DragSourceDropEvent The DragSourceDropEvent is delivered from the DragSourceContextPeer, via the DragSourceContext, to its currently registered DragSourceListener's dragDropEnd() method.
DragSourceEvent This class is the base class for DragSourceDragEvent and DragSourceDropEvent.
DropTarget The DropTarget is associated with a Component when that Component wishes to accept drops during Drag and Drop operations.
DropTarget.DropTargetAutoScroller this protected nested class implements autoscrolling
DropTargetContext A DropTargetContext is created whenever the logical cursor associated with a Drag and Drop operation coincides with the visible geometry of a Component associated with a DropTarget.
DropTargetDragEvent The DropTargetDragEvent is delivered to a DropTargetListener via its dragEnter() and dragOver() methods.
DropTargetDropEvent The DropTargetDropEvent is delivered via the DropTargetListener drop() method.
DropTargetEvent The DropTargetEvent is the base class for both the DropTargetDragEvent and the DropTargetDropEvent.
MouseDragGestureRecognizer This abstract subclass of DragGestureRecognizer defines a DragGestureRecognizer for mouse based gestures.

Exception Summary
InvalidDnDOperationException This exception is thrown by various methods in the java.awt.dnd package.

Package java.awt.dnd Description

Drag and Drop is a direct manipulation gesture found in many Graphical User Interface systems that provides a mechanism to transfer information between two entities logically associated with presentation elements in the GUI. Normally driven by a physical gesture of a human user using an appropriate input device, Drag and Drop provides both a mechanism to enable continuous feedback regarding the possible outcome of any subsequent data transfer to the user during navigation over the presentation elements in the GUI, and the facilities to provide for any subsequent data negotiation and transfer.

This package defines the classes and interfaces necessary to perform Drag and Drop operations in Java. It defines classes for the drag-source and the drop-target, as well as events for transferring the data being dragged. This package also provides a means for giving visual feedback to the user throughout the duration of the Drag and Drop operation.

A typical Drag and Drop operation can be decomposed into the following states (not entirely sequentially):

The gesture itself moves a logical cursor across the GUI hierarchy, intersecting the geometry of GUI Component(s), possibly resulting in the logical "Drag" cursor entering, crossing, and subsequently leaving Component(s) and associated DropTarget(s).

The DragSource object manifests "Drag Over" feedback to the user, in the typical case by animating the GUI Cursor associated with the logical cursor.

DropTarget objects manifest "Drag Under" feedback to the user, in the typical case, by rendering animations into their associated GUI Component(s) under the GUI Cursor.

The determination of the feedback effects, and the ultimate success or failure of the data transfer, should one occur, is parameterized as follows:


JavaTM 2 Platform
Std. Ed. v1.3

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