/** * A 1.4 application that requires the following additional files: * TreeDemoHelp.html * arnold.html * bloch.html * chan.html * jls.html * swingtutorial.html * tutorial.html * tutorialcont.html * vm.html */ import javax.swing.JEditorPane; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JSplitPane; import javax.swing.UIManager; import javax.swing.JTree; import javax.swing.tree.DefaultMutableTreeNode; import javax.swing.tree.TreeSelectionModel; import javax.swing.event.TreeSelectionEvent; import javax.swing.event.TreeSelectionListener; import java.net.URL; import java.io.IOException; import java.awt.Dimension; import java.awt.GridLayout; public class TreeDemo extends JPanel implements TreeSelectionListener { private JEditorPane htmlPane; private JTree tree; private URL helpURL; private static boolean DEBUG = false; //Optionally play with line styles. Possible values are //"Angled" (the default), "Horizontal", and "None". private static boolean playWithLineStyle = false; private static String lineStyle = "Horizontal"; //Optionally set the look and feel. private static boolean useSystemLookAndFeel = false; public TreeDemo() { super(new GridLayout(1,0)); //Create the nodes. DefaultMutableTreeNode top = new DefaultMutableTreeNode("The Java Series"); createNodes(top); //Create a tree that allows one selection at a time. tree = new JTree(top); tree.getSelectionModel().setSelectionMode (TreeSelectionModel.SINGLE_TREE_SELECTION); //Listen for when the selection changes. tree.addTreeSelectionListener(this); if (playWithLineStyle) { System.out.println("line style = " + lineStyle); tree.putClientProperty("JTree.lineStyle", lineStyle); } //Create the scroll pane and add the tree to it. JScrollPane treeView = new JScrollPane(tree); //Create the HTML viewing pane. htmlPane = new JEditorPane(); htmlPane.setEditable(false); initHelp(); JScrollPane htmlView = new JScrollPane(htmlPane); //Add the scroll panes to a split pane. JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT); splitPane.setTopComponent(treeView); splitPane.setBottomComponent(htmlView); Dimension minimumSize = new Dimension(100, 50); htmlView.setMinimumSize(minimumSize); treeView.setMinimumSize(minimumSize); splitPane.setDividerLocation(100); //XXX: ignored in some releases //of Swing. bug 4101306 //workaround for bug 4101306: //treeView.setPreferredSize(new Dimension(100, 100)); splitPane.setPreferredSize(new Dimension(500, 300)); //Add the split pane to this panel. add(splitPane); } /** Required by TreeSelectionListener interface. */ public void valueChanged(TreeSelectionEvent e) { DefaultMutableTreeNode node = (DefaultMutableTreeNode) tree.getLastSelectedPathComponent(); if (node == null) return; Object nodeInfo = node.getUserObject(); if (node.isLeaf()) { BookInfo book = (BookInfo)nodeInfo; displayURL(book.bookURL); if (DEBUG) { System.out.print(book.bookURL + ": \n "); } } else { displayURL(helpURL); } if (DEBUG) { System.out.println(nodeInfo.toString()); } } private class BookInfo { public String bookName; public URL bookURL; public BookInfo(String book, String filename) { bookName = book; bookURL = TreeDemo.class.getResource(filename); if (bookURL == null) { System.err.println("Couldn't find file: " + filename); } } public String toString() { return bookName; } } private void initHelp() { String s = "TreeDemoHelp.html"; helpURL = TreeDemo.class.getResource(s); if (helpURL == null) { System.err.println("Couldn't open help file: " + s); } else if (DEBUG) { System.out.println("Help URL is " + helpURL); } displayURL(helpURL); } private void displayURL(URL url) { try { if (url != null) { htmlPane.setPage(url); } else { //null url htmlPane.setText("File Not Found"); if (DEBUG) { System.out.println("Attempted to display a null URL."); } } } catch (IOException e) { System.err.println("Attempted to read a bad URL: " + url); } } private void createNodes(DefaultMutableTreeNode top) { DefaultMutableTreeNode category = null; DefaultMutableTreeNode book = null; category = new DefaultMutableTreeNode("Books for Java Programmers"); top.add(category); //original Tutorial book = new DefaultMutableTreeNode(new BookInfo ("The Java Tutorial: A Short Course on the Basics", "tutorial.html")); category.add(book); //Tutorial Continued book = new DefaultMutableTreeNode(new BookInfo ("The Java Tutorial Continued: The Rest of the JDK", "tutorialcont.html")); category.add(book); //JFC Swing Tutorial book = new DefaultMutableTreeNode(new BookInfo ("The JFC Swing Tutorial: A Guide to Constructing GUIs", "swingtutorial.html")); category.add(book); //Bloch book = new DefaultMutableTreeNode(new BookInfo ("Effective Java Programming Language Guide", "bloch.html")); category.add(book); //Arnold/Gosling book = new DefaultMutableTreeNode(new BookInfo ("The Java Programming Language", "arnold.html")); category.add(book); //Chan book = new DefaultMutableTreeNode(new BookInfo ("The Java Developers Almanac", "chan.html")); category.add(book); category = new DefaultMutableTreeNode("Books for Java Implementers"); top.add(category); //VM book = new DefaultMutableTreeNode(new BookInfo ("The Java Virtual Machine Specification", "vm.html")); category.add(book); //Language Spec book = new DefaultMutableTreeNode(new BookInfo ("The Java Language Specification", "jls.html")); category.add(book); } /** * Create the GUI and show it. For thread safety, * this method should be invoked from the * event-dispatching thread. */ private static void createAndShowGUI() { if (useSystemLookAndFeel) { try { UIManager.setLookAndFeel( UIManager.getSystemLookAndFeelClassName()); } catch (Exception e) { System.err.println("Couldn't use system look and feel."); } } //Create and set up the window. JFrame frame = new JFrame("TreeDemo"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Create and set up the content pane. TreeDemo newContentPane = new TreeDemo(); 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(); } }); } }
