1 reply to this topic

[brightmatter]

I am having some trouble trying to understand this concept. I am relatively new to Java and I am trying to tackle something new, GUI. I have made a simple tree with three buttons. I am trying to add the ability to drag one node from one location in the tree to another location and drop it there. I feel certain that I have run across the exact article I need to do this found here, but I am afraid that it is just a bit over my head. I wonder if anyone will be able to translate or better explain what I need to do to my code to accomplish this task. Any and all help you can provide is welcomed. The following is code that I have made in Netbeans GUI builder.

import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.UIManager;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreePath;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

/*
 * TestTree.java
 *
 * Created on Jun 3, 2009, 1:08:08 PM
 */

/**
 *
 * @author jacobenn
 */
public class TestTree extends javax.swing.JFrame {
 /** Creates new form Aonori_Test_GUI */
 public TestTree(){
  try {
   UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
  } catch (Exception ex) {
   Logger.getLogger(TestTree.class.getName()).log(Level.SEVERE, null, ex);
  } 
  initComponents();
  treeNode1 = new javax.swing.tree.DefaultMutableTreeNode("New Root Item");
  jTree1.setModel(new javax.swing.tree.DefaultTreeModel(treeNode1));
  jTree1.setEditable(true);
  jScrollPane1.setViewportView(jTree1);
 }


    /** This method is called from within the constructor to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
 // <editor-fold defaultstate="collapsed" desc="Generated Code">
 private void initComponents() {

  jScrollPane1 = new javax.swing.JScrollPane();
  jTree1 = new javax.swing.JTree();
  jButton1 = new javax.swing.JButton();
  jButton2 = new javax.swing.JButton();
  jButton3 = new javax.swing.JButton();

  setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

  jTree1.setDragEnabled(true);
  jTree1.setEditable(true);
  jTree1.setRootVisible(false);
  jTree1.setShowsRootHandles(true);
  jScrollPane1.setViewportView(jTree1);

  jButton1.setText("Delete");
  jButton1.setPreferredSize(new java.awt.Dimension(60, 20));
  jButton1.addActionListener(new java.awt.event.ActionListener() {
   public void actionPerformed(java.awt.event.ActionEvent evt) {
    jButton1ActionPerformed(evt);
   }
  });

  jButton2.setText("Add Child");
  jButton2.setPreferredSize(new java.awt.Dimension(60, 20));
  jButton2.addActionListener(new java.awt.event.ActionListener() {
   public void actionPerformed(java.awt.event.ActionEvent evt) {
    jButton2ActionPerformed(evt);
   }
  });

  jButton3.setText("Add Root");
  jButton3.setPreferredSize(new java.awt.Dimension(60, 20));
  jButton3.addActionListener(new java.awt.event.ActionListener() {
   public void actionPerformed(java.awt.event.ActionEvent evt) {
    jButton3ActionPerformed(evt);
   }
  });

  javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
  getContentPane().setLayout(layout);
  layout.setHorizontalGroup(
   layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
   .addGroup(layout.createSequentialGroup()
    .addContainerGap()
    .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
     .addComponent(jScrollPane1, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 340, Short.MAX_VALUE)
     .addGroup(layout.createSequentialGroup()
      .addComponent(jButton3, javax.swing.GroupLayout.PREFERRED_SIZE, 111, javax.swing.GroupLayout.PREFERRED_SIZE)
      .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
      .addComponent(jButton2, javax.swing.GroupLayout.PREFERRED_SIZE, 105, javax.swing.GroupLayout.PREFERRED_SIZE)
      .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
      .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 112, javax.swing.GroupLayout.PREFERRED_SIZE)))
    .addContainerGap())
  );
  layout.setVerticalGroup(
   layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
   .addGroup(layout.createSequentialGroup()
    .addContainerGap()
    .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
     .addComponent(jButton3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
     .addComponent(jButton2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
     .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
    .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
    .addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 301, Short.MAX_VALUE)
    .addContainerGap())
  );

  pack();
 }// </editor-fold>

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
     TreePath currentSelection = jTree1.getSelectionPath();
     if (currentSelection != null) {
      DefaultMutableTreeNode node = (DefaultMutableTreeNode) currentSelection.getLastPathComponent();
      DefaultTreeModel model = ((DefaultTreeModel) jTree1.getModel());
      model.removeNodeFromParent(node);
     }
    }

    private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
     TreePath currentSelection = jTree1.getSelectionPath();
     if (currentSelection != null) {
      DefaultMutableTreeNode node = (DefaultMutableTreeNode) currentSelection.getLastPathComponent();
      DefaultTreeModel model = ((DefaultTreeModel) jTree1.getModel());

      node.add(new DefaultMutableTreeNode("New Item"));
      model.nodeStructureChanged(node);
     }
    }

    private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {
     String temp = treeNode1.getRoot().toString();
     javax.swing.tree.DefaultMutableTreeNode treeNode = new javax.swing.tree.DefaultMutableTreeNode(temp);
     treeNode1.add(treeNode);
     jTree1.setModel(new javax.swing.tree.DefaultTreeModel(treeNode1));
    }

    /**
    * @param args the command line arguments
    */
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new TestTree().setVisible(true);
            }
        });
    }
javax.swing.tree.DefaultMutableTreeNode treeNode1;
 // Variables declaration - do not modify
 private javax.swing.JButton jButton1;
 private javax.swing.JButton jButton2;
 private javax.swing.JButton jButton3;
 private javax.swing.JScrollPane jScrollPane1;
 private javax.swing.JTree jTree1;
 // End of variables declaration

}

[brightmatter]

I did this.

package ICONS;

import java.awt.Point;
import java.awt.dnd.DragGestureEvent;
import java.awt.dnd.DragGestureListener;
import java.awt.dnd.DragGestureRecognizer;
import java.awt.dnd.DragSource;
import java.awt.dnd.DropTarget;
import java.awt.dnd.DropTargetContext;
import java.awt.dnd.DropTargetDragEvent;
import java.awt.dnd.DropTargetDropEvent;
import java.awt.dnd.DropTargetEvent;
import java.awt.dnd.DropTargetListener;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreePath;

public class DragNDrop implements DragGestureListener, DropTargetListener {

 DropTarget target;
 JTree sourceTree;
 DragSource source = new DragSource();
 DragGestureRecognizer recognizer;
 DefaultMutableTreeNode subTreeDuplicate = null;
 DefaultMutableTreeNode startPoint = null;

 public DragNDrop(JTree tree, int actions) {
  target = new DropTarget(tree, this);
  sourceTree = tree;
  recognizer = source.createDefaultDragGestureRecognizer(sourceTree,
          actions, this);
 }

 public void dragEnter(DropTargetDragEvent dtde) {
 }

 public void dragOver(DropTargetDragEvent dtde) {
 }

 public void dragExit(DropTargetEvent dte) {
 }

 public void dragGestureRecognized(DragGestureEvent dge) {
  TreePath path = sourceTree.getSelectionPath();
  if ((path == null) || (path.getPathCount() <= 1) || ((DefaultMutableTreeNode) path.getLastPathComponent()).isRoot()) {
   return;
  } else {
   try {
    subTreeDuplicate = recursiveTreeTools.analyzeTreePath(path);
   } catch (CloneNotSupportedException ex) {
    Logger.getLogger(DragNDrop.class.getName()).log(Level.SEVERE, null, ex);
   }
   startPoint = (DefaultMutableTreeNode) path.getLastPathComponent();
  }
 }

 public void dropActionChanged(DropTargetDragEvent dtde) {
 }

 public void drop(DropTargetDropEvent dtde) {
  DefaultMutableTreeNode dropPoint;
  if (startPoint != null && subTreeDuplicate != null) {
   Point pt = dtde.getLocation();
   DropTargetContext dtc = dtde.getDropTargetContext();
   JTree tree = (JTree) dtc.getComponent();
   TreePath parentpath = tree.getClosestPathForLocation(pt.x, pt.y);
   dropPoint = (DefaultMutableTreeNode) parentpath.getLastPathComponent();
   if (!dropPoint.equals(startPoint) && !startPoint.isNodeDescendant(dropPoint)) {
    DefaultTreeModel model = ((DefaultTreeModel) tree.getModel());
    dropPoint.add(subTreeDuplicate);
    model.removeNodeFromParent(startPoint);
    model.nodeStructureChanged(dropPoint);
   }
  }
  startPoint = null;
  subTreeDuplicate = null;
 }
}

That is the main portion of what needs to be done. Also enable some basic stuff like this under the initComponents():

    jTree1.setAutoscrolls(true);
    jTree1.setDragEnabled(true);
    jTree1.setEditable(true);
    jTree1.setShowsRootHandles(true);
    jScrollPane1.setViewportView(jTree1);
    ROOT = new javax.swing.tree.DefaultMutableTreeNode("Root");
    jTree1.setModel(new javax.swing.tree.DefaultTreeModel(ROOT));
    ds = new DragNDrop(jTree1, DnDConstants.ACTION_COPY_OR_MOVE);

If anyone has any improvements, I am all eyes.

BM