Java java.awt.dnd Class DragGestureRecognizer（JDK8）

Field Detail

• dragSource

  protected DragSource dragSource

  The DragSource associated with this DragGestureRecognizer.

• component

  protected Component component

  The Component associated with this DragGestureRecognizer.

• dragGestureListener

  protected transient DragGestureListener dragGestureListener

  The DragGestureListener associated with this DragGestureRecognizer.

• sourceActions

  protected int sourceActions

  An int representing the type(s) of action(s) used in this Drag and Drop operation.

• events

  protected ArrayList<InputEvent> events

  The list of events (in order) that the DragGestureRecognizer "recognized" as a "gesture" that triggers a drag.

Constructor Detail

• DragGestureRecognizer

  protected DragGestureRecognizer(DragSource ds,
                                  Component c,
                                  int sa,
                                  DragGestureListener dgl)

  Construct a new DragGestureRecognizer given the DragSource to be used in this Drag and Drop operation, the Component this DragGestureRecognizer should "observe" for drag initiating gestures, the action(s) supported for this Drag and Drop operation, and the DragGestureListener to notify once a drag initiating gesture has been detected.

  Parameters:

  ds - the DragSource this DragGestureRecognizer will use to process the Drag and Drop operation

  c - the Component this DragGestureRecognizer should "observe" the event stream to, in order to detect a drag initiating gesture. If this value is null, the DragGestureRecognizer is not associated with any Component.

  sa - the set (logical OR) of the DnDConstants that this Drag and Drop operation will support

  dgl - the DragGestureRecognizer to notify when a drag gesture is detected

  Throws:

  IllegalArgumentException - if ds is null.

• DragGestureRecognizer

  protected DragGestureRecognizer(DragSource ds,
                                  Component c,
                                  int sa)

  Construct a new DragGestureRecognizer given the DragSource to be used in this Drag and Drop operation, the Component this DragGestureRecognizer should "observe" for drag initiating gestures, and the action(s) supported for this Drag and Drop operation.

  Parameters:

  ds - the DragSource this DragGestureRecognizer will use to process the Drag and Drop operation

  c - the Component this DragGestureRecognizer should "observe" the event stream to, in order to detect a drag initiating gesture. If this value is null, the DragGestureRecognizer is not associated with any Component.

  sa - the set (logical OR) of the DnDConstants that this Drag and Drop operation will support

  Throws:

  IllegalArgumentException - if ds is null.

• DragGestureRecognizer

  protected DragGestureRecognizer(DragSource ds,
                                  Component c)

  Construct a new DragGestureRecognizer given the DragSource to be used in this Drag and Drop operation, and the Component this DragGestureRecognizer should "observe" for drag initiating gestures.

  Parameters:

  ds - the DragSource this DragGestureRecognizer will use to process the Drag and Drop operation

  c - the Component this DragGestureRecognizer should "observe" the event stream to, in order to detect a drag initiating gesture. If this value is null, the DragGestureRecognizer is not associated with any Component.

  Throws:

  IllegalArgumentException - if ds is null.

• DragGestureRecognizer

  protected DragGestureRecognizer(DragSource ds)

  Construct a new DragGestureRecognizer given the DragSource to be used in this Drag and Drop operation.

  Parameters:

  ds - the DragSource this DragGestureRecognizer will use to process the Drag and Drop operation

  Throws:

  IllegalArgumentException - if ds is null.

Method Detail

• registerListeners

  protected abstract void registerListeners()

  register this DragGestureRecognizer's Listeners with the Component subclasses must override this method

• unregisterListeners

  protected abstract void unregisterListeners()

  unregister this DragGestureRecognizer's Listeners with the Component subclasses must override this method

• getDragSource

  public DragSource getDragSource()

  This method returns the DragSource this DragGestureRecognizer will use in order to process the Drag and Drop operation.

  Returns:

  the DragSource

• getComponent

  public Component getComponent()

  This method returns the Component that is to be "observed" by the DragGestureRecognizer for drag initiating gestures.

  Returns:

  The Component this DragGestureRecognizer is associated with

• setComponent

  public void setComponent(Component c)

  set the Component that the DragGestureRecognizer is associated with registerListeners() and unregisterListeners() are called as a side effect as appropriate.

  Parameters:

  c - The Component or null

• getSourceActions

  public int getSourceActions()

  This method returns an int representing the type of action(s) this Drag and Drop operation will support.

  Returns:

  the currently permitted source action(s)

• setSourceActions

  public void setSourceActions(int actions)

  This method sets the permitted source drag action(s) for this Drag and Drop operation.

  Parameters:

  actions - the permitted source drag action(s)

• getTriggerEvent

  public InputEvent getTriggerEvent()

  This method returns the first event in the series of events that initiated the Drag and Drop operation.

  Returns:

  the initial event that triggered the drag gesture

• resetRecognizer

  public void resetRecognizer()

  Reset the Recognizer, if its currently recognizing a gesture, ignore it.

• addDragGestureListener

  public void addDragGestureListener(DragGestureListener dgl)
                              throws TooManyListenersException

  Register a new DragGestureListener.

  Parameters:

  dgl - the DragGestureListener to register with this DragGestureRecognizer.

  Throws:

  TooManyListenersException - if a DragGestureListener has already been added.

• removeDragGestureListener

  public void removeDragGestureListener(DragGestureListener dgl)

  unregister the current DragGestureListener

  Parameters:

  dgl - the DragGestureListener to unregister from this DragGestureRecognizer

  Throws:

  IllegalArgumentException - if dgl is not (equal to) the currently registered DragGestureListener.

• fireDragGestureRecognized

  protected void fireDragGestureRecognized(int dragAction,
                                           Point p)

  Notify the DragGestureListener that a Drag and Drop initiating gesture has occurred. Then reset the state of the Recognizer.

  Parameters:

  dragAction - The action initially selected by the users gesture

  p - The point (in Component coords) where the gesture originated

• appendEvent

  protected void appendEvent(InputEvent awtie)

  Listeners registered on the Component by this Recognizer shall record all Events that are recognized as part of the series of Events that go to comprise a Drag and Drop initiating gesture via this API.

  This method is used by a DragGestureRecognizer implementation to add an InputEvent subclass (that it believes is one in a series of events that comprise a Drag and Drop operation) to the array of events that this DragGestureRecognizer maintains internally.

  Parameters:

  awtie - the InputEvent to add to this DragGestureRecognizer's internal array of events. Note that null is not a valid value, and will be ignored.