关于JTree的图标显示

Question

我想在树中显示不同的图标，就是让不同的目录使用我指定的图片做图标，但不清楚怎么做，清赐教，谢谢！

Answer 1

这个比较简单，用DefaultTreeCellRenderer应该就可以实现

Answer 2

楼主可以参考一下JDK的例子：
/**
 * 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.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.TreeSelectionModel;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.ToolTipManager;
import javax.swing.ImageIcon;
import javax.swing.Icon;import java.net.URL;
import java.io.IOException;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.Component;
public class TreeIconDemo2 extends JPanel 
                           implements TreeSelectionListener {
    private JEditorPane htmlPane;
    private JTree tree;
    private URL helpURL;
    private static boolean DEBUG = false;    public TreeIconDemo2() {
        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);        //Enable tool tips.
        ToolTipManager.sharedInstance().registerComponent(tree);        //Set the icon for leaf nodes.
        ImageIcon tutorialIcon = createImageIcon("images/middle.gif");
        if (tutorialIcon != null) {
            tree.setCellRenderer(new MyRenderer(tutorialIcon));
        } else {
            System.err.println("Tutorial icon missing; using default.");
        }        //Listen for when the selection changes.
        tree.addTreeSelectionListener(this);        //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 = TreeIconDemo.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 = TreeIconDemo.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);
    }

Answer 3

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);
    }    /** Returns an ImageIcon, or null if the path was invalid. */
    protected static ImageIcon createImageIcon(String path) {
        java.net.URL imgURL = TreeIconDemo2.class.getResource(path);
        if (imgURL != null) {
            return new ImageIcon(imgURL);
        } else {
            System.err.println("Couldn't find file: " + path);
            return null;
        }
    }    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() {
        //Make sure we have nice window decorations.
        JFrame.setDefaultLookAndFeelDecorated(true);        //Create and set up the window.
        JFrame frame = new JFrame("TreeIconDemo2");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        //Create and set up the content pane.
        TreeIconDemo2 newContentPane = new TreeIconDemo2();
        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();
            }
        });
    }    private class MyRenderer extends DefaultTreeCellRenderer {
        Icon tutorialIcon;        public MyRenderer(Icon icon) {
            tutorialIcon = icon;
        }        public Component getTreeCellRendererComponent(
                            JTree tree,
                            Object value,
                            boolean sel,
                            boolean expanded,
                            boolean leaf,
                            int row,
                            boolean hasFocus) {            super.getTreeCellRendererComponent(
                            tree, value, sel,
                            expanded, leaf, row,
                            hasFocus);
            if (leaf && isTutorialBook(value)) {
                setIcon(tutorialIcon);
                setToolTipText("This book is in the Tutorial series.");
            } else {
                setToolTipText(null); //no tool tip
            }            return this;
        }        protected boolean isTutorialBook(Object value) {
            DefaultMutableTreeNode node =
                    (DefaultMutableTreeNode)value;
            BookInfo nodeInfo = 
                    (BookInfo)(node.getUserObject());
            String title = nodeInfo.bookName;
            if (title.indexOf("Tutorial") >= 0) {
                return true;
            }             return false;
        }
    }
}

Answer 4

JTree tree;
 DefaultMutableTreeNode tp1;
 DefaultTreeModel treeModel;
 DefaultTreeCellRenderer r = new DefaultTreeCellRenderer();tp1 = new DefaultMutableTreeNode(myname);
treeModel=new DefaultTreeModel(tp1);r.setLeafIcon(new ImageIcon("image/qq.gif"));
r.setOpenIcon(new ImageIcon("image/qq.gif"));
r.setClosedIcon(new ImageIcon("image/qq.gif"));
tree.setCellRenderer(r);tree=new JTree(treeModel);这个简单的够不？
不够可以给多点分吧？