author | weijun |
Thu, 11 Dec 2014 15:19:12 +0800 | |
changeset 28228 | be83f404724d |
parent 25859 | 3317bb8137f4 |
permissions | -rw-r--r-- |
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/* |
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* Copyright (c) 2005, 2008, Oracle and/or its affiliates. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. Oracle designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Oracle in the LICENSE file that accompanied this code. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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*/ |
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package javax.swing.plaf.basic; |
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import java.awt.Toolkit; |
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import java.awt.event.*; |
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import java.awt.dnd.DragSource; |
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import javax.swing.*; |
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import sun.awt.dnd.SunDragSourceContextPeer; |
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import sun.awt.AppContext; |
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/** |
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* Drag gesture recognition support for classes that have a |
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* <code>TransferHandler</code>. The gesture for a drag in this class is a mouse |
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* press followed by movement by <code>DragSource.getDragThreshold()</code> |
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* pixels. An instance of this class is maintained per AppContext, and the |
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* public static methods call into the appropriate instance. |
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* |
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* @author Shannon Hickey |
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*/ |
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class DragRecognitionSupport { |
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private int motionThreshold; |
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private MouseEvent dndArmedEvent; |
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private JComponent component; |
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/** |
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* This interface allows us to pass in a handler to mouseDragged, |
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* so that we can be notified immediately before a drag begins. |
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*/ |
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public static interface BeforeDrag { |
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public void dragStarting(MouseEvent me); |
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} |
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/** |
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* Returns the DragRecognitionSupport for the caller's AppContext. |
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*/ |
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private static DragRecognitionSupport getDragRecognitionSupport() { |
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DragRecognitionSupport support = |
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(DragRecognitionSupport)AppContext.getAppContext(). |
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get(DragRecognitionSupport.class); |
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if (support == null) { |
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support = new DragRecognitionSupport(); |
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AppContext.getAppContext().put(DragRecognitionSupport.class, support); |
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} |
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return support; |
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} |
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/** |
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* Returns whether or not the event is potentially part of a drag sequence. |
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*/ |
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public static boolean mousePressed(MouseEvent me) { |
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return getDragRecognitionSupport().mousePressedImpl(me); |
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} |
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/** |
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* If a dnd recognition has been going on, return the MouseEvent |
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* that started the recognition. Otherwise, return null. |
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*/ |
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public static MouseEvent mouseReleased(MouseEvent me) { |
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return getDragRecognitionSupport().mouseReleasedImpl(me); |
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} |
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/** |
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* Returns whether or not a drag gesture recognition is ongoing. |
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*/ |
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public static boolean mouseDragged(MouseEvent me, BeforeDrag bd) { |
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rupashka
parents:
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diff
changeset
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return getDragRecognitionSupport().mouseDraggedImpl(me, bd); |
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} |
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private void clearState() { |
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dndArmedEvent = null; |
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component = null; |
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} |
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private int mapDragOperationFromModifiers(MouseEvent me, |
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TransferHandler th) { |
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if (th == null || !SwingUtilities.isLeftMouseButton(me)) { |
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return TransferHandler.NONE; |
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} |
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return SunDragSourceContextPeer. |
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convertModifiersToDropAction(me.getModifiersEx(), |
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th.getSourceActions(component)); |
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} |
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/** |
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* Returns whether or not the event is potentially part of a drag sequence. |
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*/ |
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private boolean mousePressedImpl(MouseEvent me) { |
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component = (JComponent)me.getSource(); |
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if (mapDragOperationFromModifiers(me, component.getTransferHandler()) |
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!= TransferHandler.NONE) { |
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motionThreshold = DragSource.getDragThreshold(); |
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dndArmedEvent = me; |
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return true; |
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} |
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clearState(); |
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return false; |
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} |
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/** |
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* If a dnd recognition has been going on, return the MouseEvent |
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* that started the recognition. Otherwise, return null. |
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*/ |
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private MouseEvent mouseReleasedImpl(MouseEvent me) { |
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/* no recognition has been going on */ |
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if (dndArmedEvent == null) { |
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return null; |
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} |
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MouseEvent retEvent = null; |
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if (me.getSource() == component) { |
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retEvent = dndArmedEvent; |
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} // else component has changed unexpectedly, so return null |
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clearState(); |
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return retEvent; |
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} |
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/** |
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* Returns whether or not a drag gesture recognition is ongoing. |
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*/ |
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private boolean mouseDraggedImpl(MouseEvent me, BeforeDrag bd) { |
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/* no recognition is in progress */ |
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if (dndArmedEvent == null) { |
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return false; |
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} |
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/* component has changed unexpectedly, so bail */ |
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if (me.getSource() != component) { |
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clearState(); |
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return false; |
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} |
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int dx = Math.abs(me.getX() - dndArmedEvent.getX()); |
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int dy = Math.abs(me.getY() - dndArmedEvent.getY()); |
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if ((dx > motionThreshold) || (dy > motionThreshold)) { |
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TransferHandler th = component.getTransferHandler(); |
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int action = mapDragOperationFromModifiers(me, th); |
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if (action != TransferHandler.NONE) { |
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/* notify the BeforeDrag instance */ |
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if (bd != null) { |
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bd.dragStarting(dndArmedEvent); |
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} |
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th.exportAsDrag(component, dndArmedEvent, action); |
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clearState(); |
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} |
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} |
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return true; |
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} |
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} |