Mega Code Archive
This program demonstrates tree editing
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/*
This program is a part of the companion code for Core Java 8th ed.
(http://horstmann.com/corejava)
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreeNode;
import javax.swing.tree.TreePath;
/**
* This program demonstrates tree editing.
* @version 1.03 2007-08-01
* @author Cay Horstmann
*/
public class TreeEditTest
{
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
JFrame frame = new TreeEditFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
});
}
}
/**
* A frame with a tree and buttons to edit the tree.
*/
class TreeEditFrame extends JFrame
{
public TreeEditFrame()
{
setTitle("TreeEditTest");
setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
// construct tree
TreeNode root = makeSampleTree();
model = new DefaultTreeModel(root);
tree = new JTree(model);
tree.setEditable(true);
// add scroll pane with tree
JScrollPane scrollPane = new JScrollPane(tree);
add(scrollPane, BorderLayout.CENTER);
makeButtons();
}
public TreeNode makeSampleTree()
{
DefaultMutableTreeNode root = new DefaultMutableTreeNode("World");
DefaultMutableTreeNode country = new DefaultMutableTreeNode("USA");
root.add(country);
DefaultMutableTreeNode state = new DefaultMutableTreeNode("California");
country.add(state);
DefaultMutableTreeNode city = new DefaultMutableTreeNode("San Jose");
state.add(city);
city = new DefaultMutableTreeNode("San Diego");
state.add(city);
state = new DefaultMutableTreeNode("Michigan");
country.add(state);
city = new DefaultMutableTreeNode("Ann Arbor");
state.add(city);
country = new DefaultMutableTreeNode("Germany");
root.add(country);
state = new DefaultMutableTreeNode("Schleswig-Holstein");
country.add(state);
city = new DefaultMutableTreeNode("Kiel");
state.add(city);
return root;
}
/**
* Makes the buttons to add a sibling, add a child, and delete a node.
*/
public void makeButtons()
{
JPanel panel = new JPanel();
JButton addSiblingButton = new JButton("Add Sibling");
addSiblingButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
DefaultMutableTreeNode selectedNode = (DefaultMutableTreeNode) tree
.getLastSelectedPathComponent();
if (selectedNode == null) return;
DefaultMutableTreeNode parent = (DefaultMutableTreeNode) selectedNode.getParent();
if (parent == null) return;
DefaultMutableTreeNode newNode = new DefaultMutableTreeNode("New");
int selectedIndex = parent.getIndex(selectedNode);
model.insertNodeInto(newNode, parent, selectedIndex + 1);
// now display new node
TreeNode[] nodes = model.getPathToRoot(newNode);
TreePath path = new TreePath(nodes);
tree.scrollPathToVisible(path);
}
});
panel.add(addSiblingButton);
JButton addChildButton = new JButton("Add Child");
addChildButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
DefaultMutableTreeNode selectedNode = (DefaultMutableTreeNode) tree
.getLastSelectedPathComponent();
if (selectedNode == null) return;
DefaultMutableTreeNode newNode = new DefaultMutableTreeNode("New");
model.insertNodeInto(newNode, selectedNode, selectedNode.getChildCount());
// now display new node
TreeNode[] nodes = model.getPathToRoot(newNode);
TreePath path = new TreePath(nodes);
tree.scrollPathToVisible(path);
}
});
panel.add(addChildButton);
JButton deleteButton = new JButton("Delete");
deleteButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
DefaultMutableTreeNode selectedNode = (DefaultMutableTreeNode) tree
.getLastSelectedPathComponent();
if (selectedNode != null && selectedNode.getParent() != null) model
.removeNodeFromParent(selectedNode);
}
});
panel.add(deleteButton);
add(panel, BorderLayout.SOUTH);
}
private DefaultTreeModel model;
private JTree tree;
private static final int DEFAULT_WIDTH = 400;
private static final int DEFAULT_HEIGHT = 200;
}
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