Java examples for Swing:JTree
Handle Tree Expand Event
/*//from www . j av a2s. co m * TreeExpandEventDemo.java requires no other files. */ import javax.swing.*; import javax.swing.tree.*; import javax.swing.event.*; import java.awt.*; public class TreeExpandEventDemo extends JPanel { DemoArea demoArea; JTextArea textArea; final static String newline = "\n"; public TreeExpandEventDemo() { super(new GridBagLayout()); GridBagLayout gridbag = (GridBagLayout) getLayout(); GridBagConstraints c = new GridBagConstraints(); 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); 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); add(scrollPane); setPreferredSize(new Dimension(450, 450)); setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20)); } 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); } } /** * Create the GUI and show it. For thread safety, * this method should be invoked from the * event-dispatching thread. */ private static void createAndShowGUI() { //Create and set up the window. JFrame frame = new JFrame("TreeExpandEventDemo"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Create and set up the content pane. JComponent newContentPane = new TreeExpandEventDemo(); newContentPane.setOpaque(true); //content panes must be opaque frame.setContentPane(newContentPane); //Display the window. frame.pack(); frame.setVisible(true); } public static void main(String[] args) { //Schedule a job for the event-dispatching thread: //creating and showing this application's GUI. javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGUI(); } }); } } /* * Copyright (c) 1995, 2008, Oracle and/or its affiliates. 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