Java java.awt.dnd Class DropTarget（JDK8）

Constructor Detail

• DropTarget

  public DropTarget(Component c,
                    int ops,
                    DropTargetListener dtl,
                    boolean act,
                    FlavorMap fm)
             throws HeadlessException

  Creates a new DropTarget given the Component to associate itself with, an int representing the default acceptable action(s) to support, a DropTargetListener to handle event processing, a boolean indicating if the DropTarget is currently accepting drops, and a FlavorMap to use (or null for the default FlavorMap).

  The Component will receive drops only if it is enabled.

  Parameters:

  c - The Component with which this DropTarget is associated

  ops - The default acceptable actions for this DropTarget

  dtl - The DropTargetListener for this DropTarget

  act - Is the DropTarget accepting drops.

  fm - The FlavorMap to use, or null for the default FlavorMap

  Throws:

  HeadlessException - if GraphicsEnvironment.isHeadless() returns true

  See Also:

  GraphicsEnvironment.isHeadless()

• DropTarget

  public DropTarget(Component c,
                    int ops,
                    DropTargetListener dtl,
                    boolean act)
             throws HeadlessException

  Creates a DropTarget given the Component to associate itself with, an int representing the default acceptable action(s) to support, a DropTargetListener to handle event processing, and a boolean indicating if the DropTarget is currently accepting drops.

  The Component will receive drops only if it is enabled.

  Parameters:

  c - The Component with which this DropTarget is associated

  ops - The default acceptable actions for this DropTarget

  dtl - The DropTargetListener for this DropTarget

  act - Is the DropTarget accepting drops.

  Throws:

  HeadlessException - if GraphicsEnvironment.isHeadless() returns true

  See Also:

  GraphicsEnvironment.isHeadless()

• DropTarget

  public DropTarget()
             throws HeadlessException

  Creates a DropTarget.

  Throws:

  HeadlessException - if GraphicsEnvironment.isHeadless() returns true

  See Also:

  GraphicsEnvironment.isHeadless()

• DropTarget

  public DropTarget(Component c,
                    DropTargetListener dtl)
             throws HeadlessException

  Creates a DropTarget given the Component to associate itself with, and the DropTargetListener to handle event processing.

  The Component will receive drops only if it is enabled.

  Parameters:

  c - The Component with which this DropTarget is associated

  dtl - The DropTargetListener for this DropTarget

  Throws:

  HeadlessException - if GraphicsEnvironment.isHeadless() returns true

  See Also:

  GraphicsEnvironment.isHeadless()

• DropTarget

  public DropTarget(Component c,
                    int ops,
                    DropTargetListener dtl)
             throws HeadlessException

  Creates a DropTarget given the Component to associate itself with, an int representing the default acceptable action(s) to support, and a DropTargetListener to handle event processing.

  The Component will receive drops only if it is enabled.

  Parameters:

  c - The Component with which this DropTarget is associated

  ops - The default acceptable actions for this DropTarget

  dtl - The DropTargetListener for this DropTarget

  Throws:

  HeadlessException - if GraphicsEnvironment.isHeadless() returns true

  See Also:

  GraphicsEnvironment.isHeadless()

Method Detail

• setComponent

  public void setComponent(Component c)

  Note: this interface is required to permit the safe association of a DropTarget with a Component in one of two ways, either: component.setDropTarget(droptarget); or droptarget.setComponent(component);

  The Component will receive drops only if it is enabled.

  Parameters:

  c - The new Component this DropTarget is to be associated with.

• getComponent

  public Component getComponent()

  Gets the Component associated with this DropTarget.

  Returns:

  the current Component

• setDefaultActions

  public void setDefaultActions(int ops)

  Sets the default acceptable actions for this DropTarget

  Parameters:

  ops - the default actions

  See Also:

  DnDConstants

• getDefaultActions

  public int getDefaultActions()

  Gets an int representing the current action(s) supported by this DropTarget.

  Returns:

  the current default actions

• setActive

  public void setActive(boolean isActive)

  Sets the DropTarget active if true, inactive if false.

  Parameters:

  isActive - sets the DropTarget (in)active.

• isActive

  public boolean isActive()

  Reports whether or not this DropTarget is currently active (ready to accept drops).

  Returns:

  true if active, false if not

• addDropTargetListener

  public void addDropTargetListener(DropTargetListener dtl)
                             throws TooManyListenersException

  Adds a new DropTargetListener (UNICAST SOURCE).

  Parameters:

  dtl - The new DropTargetListener

  Throws:

  TooManyListenersException - if a DropTargetListener is already added to this DropTarget.

• removeDropTargetListener

  public void removeDropTargetListener(DropTargetListener dtl)

  Removes the current DropTargetListener (UNICAST SOURCE).

  Parameters:

  dtl - the DropTargetListener to deregister.

• dragEnter

  public void dragEnter(DropTargetDragEvent dtde)

  Calls dragEnter on the registered DropTargetListener and passes it the specified DropTargetDragEvent. Has no effect if this DropTarget is not active.

  Specified by:

  dragEnter in interface DropTargetListener

  Parameters:

  dtde - the DropTargetDragEvent

  Throws:

  NullPointerException - if this DropTarget is active and dtde is null

  See Also:

  isActive()

• dragOver

  public void dragOver(DropTargetDragEvent dtde)

  Calls dragOver on the registered DropTargetListener and passes it the specified DropTargetDragEvent. Has no effect if this DropTarget is not active.

  Specified by:

  dragOver in interface DropTargetListener

  Parameters:

  dtde - the DropTargetDragEvent

  Throws:

  NullPointerException - if this DropTarget is active and dtde is null

  See Also:

  isActive()

• dropActionChanged

  public void dropActionChanged(DropTargetDragEvent dtde)

  Calls dropActionChanged on the registered DropTargetListener and passes it the specified DropTargetDragEvent. Has no effect if this DropTarget is not active.

  Specified by:

  dropActionChanged in interface DropTargetListener

  Parameters:

  dtde - the DropTargetDragEvent

  Throws:

  NullPointerException - if this DropTarget is active and dtde is null

  See Also:

  isActive()

• dragExit

  public void dragExit(DropTargetEvent dte)

  Calls dragExit on the registered DropTargetListener and passes it the specified DropTargetEvent. Has no effect if this DropTarget is not active.

  This method itself does not throw any exception for null parameter but for exceptions thrown by the respective method of the listener.

  Specified by:

  dragExit in interface DropTargetListener

  Parameters:

  dte - the DropTargetEvent

  See Also:

  isActive()

• drop

  public void drop(DropTargetDropEvent dtde)

  Calls drop on the registered DropTargetListener and passes it the specified DropTargetDropEvent if this DropTarget is active.

  Specified by:

  drop in interface DropTargetListener

  Parameters:

  dtde - the DropTargetDropEvent

  Throws:

  NullPointerException - if dtde is null and at least one of the following is true: this DropTarget is not active, or there is no a DropTargetListener registered.

  See Also:

  isActive()

• getFlavorMap

  public FlavorMap getFlavorMap()

  Gets the FlavorMap associated with this DropTarget. If no FlavorMap has been set for this DropTarget, it is associated with the default FlavorMap.

  Returns:

  the FlavorMap for this DropTarget

• setFlavorMap

  public void setFlavorMap(FlavorMap fm)

  Sets the FlavorMap associated with this DropTarget.

  Parameters:

  fm - the new FlavorMap, or null to associate the default FlavorMap with this DropTarget.

• addNotify

  public void addNotify(java.awt.peer.ComponentPeer peer)

  Notify the DropTarget that it has been associated with a Component This method is usually called from java.awt.Component.addNotify() of the Component associated with this DropTarget to notify the DropTarget that a ComponentPeer has been associated with that Component. Calling this method, other than to notify this DropTarget of the association of the ComponentPeer with the Component may result in a malfunction of the DnD system.

  Parameters:

  peer - The Peer of the Component we are associated with!

• removeNotify

  public void removeNotify(java.awt.peer.ComponentPeer peer)

  Notify the DropTarget that it has been disassociated from a Component This method is usually called from java.awt.Component.removeNotify() of the Component associated with this DropTarget to notify the DropTarget that a ComponentPeer has been disassociated with that Component. Calling this method, other than to notify this DropTarget of the disassociation of the ComponentPeer from the Component may result in a malfunction of the DnD system.

  Parameters:

  peer - The Peer of the Component we are being disassociated from!

• getDropTargetContext

  public DropTargetContext getDropTargetContext()

  Gets the DropTargetContext associated with this DropTarget.

  Returns:

  the DropTargetContext associated with this DropTarget.

• createDropTargetContext

  protected DropTargetContext createDropTargetContext()

  Creates the DropTargetContext associated with this DropTarget. Subclasses may override this method to instantiate their own DropTargetContext subclass. This call is typically *only* called by the platform's DropTargetContextPeer as a drag operation encounters this DropTarget. Accessing the Context while no Drag is current has undefined results.

• createDropTargetAutoScroller

  protected DropTarget.DropTargetAutoScroller createDropTargetAutoScroller(Component c,
                                                                           Point p)

  create an embedded autoscroller

  Parameters:

  c - the Component

  p - the Point

• initializeAutoscrolling

  protected void initializeAutoscrolling(Point p)

  initialize autoscrolling

  Parameters:

  p - the Point

• updateAutoscroll

  protected void updateAutoscroll(Point dragCursorLocn)

  update autoscrolling with current cursor location

  Parameters:

  dragCursorLocn - the Point

• clearAutoscroll

  protected void clearAutoscroll()

  clear autoscrolling