Mega Code Archive
Build a tree based on DefaultMutableTreeNode
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// : c14:Trees.java
// Simple Swing tree. Trees can be vastly more complex.
// <applet code=Trees width=250 height=250></applet>
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JApplet;
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;
// Takes an array of Strings and makes the first
// element a node and the rest leaves:
class Branch {
private DefaultMutableTreeNode r;
public Branch(String[] data) {
r = new DefaultMutableTreeNode(data[0]);
for (int i = 1; i < data.length; i++)
r.add(new DefaultMutableTreeNode(data[i]));
}
public DefaultMutableTreeNode node() {
return r;
}
}
public class Trees extends JApplet {
private String[][] data = { { "Colors", "Red", "Blue", "Green" },
{ "Flavors", "Tart", "Sweet", "Bland" },
{ "Length", "Short", "Medium", "Long" },
{ "Volume", "High", "Medium", "Low" },
{ "Temperature", "High", "Medium", "Low" },
{ "Intensity", "High", "Medium", "Low" }, };
private static int i = 0;
private DefaultMutableTreeNode root, child, chosen;
private JTree tree;
private DefaultTreeModel model;
public void init() {
Container cp = getContentPane();
root = new DefaultMutableTreeNode("root");
tree = new JTree(root);
// Add it and make it take care of scrolling:
cp.add(new JScrollPane(tree), BorderLayout.CENTER);
// Capture the tree's model:
model = (DefaultTreeModel) tree.getModel();
JButton test = new JButton("Press me");
test.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (i < data.length) {
child = new Branch(data[i++]).node();
// What's the last one you clicked?
chosen = (DefaultMutableTreeNode) tree
.getLastSelectedPathComponent();
if (chosen == null)
chosen = root;
// The model will create the appropriate event.
// In response, the tree will update itself:
model.insertNodeInto(child, chosen, 0);
// Puts the new node on the chosen node.
}
}
});
// Change the button's colors:
test.setBackground(Color.BLUE);
test.setForeground(Color.WHITE);
JPanel p = new JPanel();
p.add(test);
cp.add(p, BorderLayout.SOUTH);
}
public static void main(String[] args) {
run(new Trees(), 250, 250);
}
public static void run(JApplet applet, int width, int height) {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(applet);
frame.setSize(width, height);
applet.init();
applet.start();
frame.setVisible(true);
}
} ///:~
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