import javax.swing.*;
import javax.swing.tree.*;
import javax.swing.event.*;
import java.awt.*;
public class TreeExpandEventDemo extends JApplet {
DemoArea demoArea;
JTextArea textArea;
final static String newline = "\n";
public void init() {
GridBagLayout gridbag = new GridBagLayout();
GridBagConstraints c = new GridBagConstraints();
JPanel contentPane = new JPanel();
contentPane.setLayout(gridbag);
c.fill = GridBagConstraints.BOTH;
c.gridwidth = GridBagConstraints.REMAINDER;
c.weightx = 1.0;
c.weighty = 1.0;
c.insets = new Insets(1, 1, 1, 1);
demoArea = new DemoArea();
gridbag.setConstraints(demoArea, c);
contentPane.add(demoArea);
c.insets = new Insets(0, 0, 0, 0);
textArea = new JTextArea();
textArea.setEditable(false);
JScrollPane scrollPane = new JScrollPane(textArea);
scrollPane.setVerticalScrollBarPolicy(
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
scrollPane.setPreferredSize(new Dimension(200, 75));
gridbag.setConstraints(scrollPane, c);
contentPane.add(scrollPane);
setContentPane(contentPane);
}
void saySomething(String eventDescription, TreeExpansionEvent e) {
textArea.append(eventDescription + "; "
+ "path = " + e.getPath()
+ newline);
}
class DemoArea extends JScrollPane
implements TreeExpansionListener {
Dimension minSize = new Dimension(100, 100);
JTree tree;
public DemoArea() {
TreeNode rootNode = createNodes();
tree = new JTree(rootNode);
tree.addTreeExpansionListener(this);
setViewportView(tree);
}
private TreeNode createNodes() {
DefaultMutableTreeNode root;
DefaultMutableTreeNode grandparent;
DefaultMutableTreeNode parent;
DefaultMutableTreeNode child;
root = new DefaultMutableTreeNode("San Francisco");
grandparent = new DefaultMutableTreeNode("Potrero Hill");
root.add(grandparent);
//
parent = new DefaultMutableTreeNode("Restaurants");
grandparent.add(parent);
child = new DefaultMutableTreeNode("Thai Barbeque");
parent.add(child);
child = new DefaultMutableTreeNode("Goat Hill Pizza");
parent.add(child);
//
parent = new DefaultMutableTreeNode("Grocery Stores");
grandparent.add(parent);
child = new DefaultMutableTreeNode("Good Life Grocery");
parent.add(child);
child = new DefaultMutableTreeNode("Safeway");
parent.add(child);
grandparent = new DefaultMutableTreeNode("Noe Valley");
root.add(grandparent);
//
parent = new DefaultMutableTreeNode("Restaurants");
grandparent.add(parent);
child = new DefaultMutableTreeNode("Hamano Sushi");
parent.add(child);
child = new DefaultMutableTreeNode("Hahn's Hibachi");
parent.add(child);
//
parent = new DefaultMutableTreeNode("Grocery Stores");
grandparent.add(parent);
child = new DefaultMutableTreeNode("Real Foods");
parent.add(child);
child = new DefaultMutableTreeNode("Bell Market");
parent.add(child);
return root;
}
public Dimension getMinimumSize() {
return minSize;
}
public Dimension getPreferredSize() {
return minSize;
}
// Required by TreeExpansionListener interface.
public void treeExpanded(TreeExpansionEvent e) {
saySomething("Tree-expanded event detected", e);
}
// Required by TreeExpansionListener interface.
public void treeCollapsed(TreeExpansionEvent e) {
saySomething("Tree-collapsed event detected", e);
}
}
}
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