dragsourcetree.java

在JAVA中如何实现两棵树之间的拖拽功能.

package twotreedrag;

import javax.swing.JTree;
import java.awt.dnd.DragGestureListener;
import java.awt.dnd.DragSourceListener;
import java.awt.dnd.DragSourceDragEvent;
import java.awt.dnd.DragSourceEvent;
import java.awt.dnd.DragSourceDropEvent;
import java.awt.dnd.DragGestureEvent;
import java.awt.dnd.DragSource;
import javax.swing.tree.DefaultMutableTreeNode;
import java.awt.datatransfer.StringSelection;



/**
*

Title: JTree之间的拖拽中的DragSourceTree


*
Description:通过向从“源树”中拖拽结点在目标树中重新构造一棵树，实现JTree之间的拖拽单向拖拽，这个类是“源树”。


* @author awaysrain(绝对零度)
* @version 1.0
*/



public class DragSourceTree
extends JTree
implements DragGestureListener, DragSourceListener {
private DragSource dragSource = null;
/**
* Construct the source tree
*/
public DragSourceTree() {
super();
dragSource = DragSource.getDefaultDragSource();
dragSource.createDefaultDragGestureRecognizer(this,
java.awt.dnd.DnDConstants.
ACTION_COPY_OR_MOVE, this);
}
/**
* Construct the source tree
* @param treeNode DefaultMutableTreeNode
*/
public DragSourceTree(DefaultMutableTreeNode treeNode) {
super(treeNode);
dragSource = DragSource.getDefaultDragSource();
dragSource.createDefaultDragGestureRecognizer(this,
java.awt.dnd.DnDConstants.
ACTION_COPY_OR_MOVE, this);
}



/**
* dragGestureRecognized
*
* @param dge DragGestureEvent
*/
public void dragGestureRecognized(DragGestureEvent dge) {
java.awt.Cursor cursor = null;
cursor = DragSource.DefaultCopyDrop; //set cursor
java.awt.Point jap = dge.getDragOrigin(); //drag point
int x = (int) jap.getX();
int y = (int) jap.getY();
javax.swing.tree.TreePath tp = this.getPathForLocation(x, y); //get drag node path
if (tp != null) {
DefaultMutableTreeNode node1 = (DefaultMutableTreeNode)
tp.getLastPathComponent(); //get drag node
serializableNode(node1); //Serializable node object
}
//event start
dge.startDrag(cursor, new StringSelection("drag"), this);



}



/**
* dragEnter
*
* @param dsde DragSourceDragEvent
*/
public void dragEnter(DragSourceDragEvent dsde) {
}



/**
* dragOver
*
* @param dsde DragSourceDragEvent
*/
public void dragOver(DragSourceDragEvent dsde) {
}



/**
* dropActionChanged
*
* @param dsde DragSourceDragEvent
*/
public void dropActionChanged(DragSourceDragEvent dsde) {
}



/**
* dragDropEnd
*
* @param dsde DragSourceDropEvent
*/
public void dragDropEnd(DragSourceDropEvent dsde) {
}



/**
* dragExit
*
* @param dse DragSourceEvent
*/
public void dragExit(DragSourceEvent dse) {
}
/**
*Serializable node
*
* @param node DefaultMutableTreeNode
*/
private void serializableNode(DefaultMutableTreeNode node) {
try {
java.io.FileOutputStream objfile = new java.io.FileOutputStream(
"DragNode.OBJ");
java.io.ObjectOutputStream p = new java.io.ObjectOutputStream(objfile);
p.writeObject(node);
p.flush();
objfile.close();
}
catch (java.io.IOException e) {
System.out.println(e.toString());
}



}
}