Java Tutorial/Swing Event/TreeSelectionListener
Содержание
Add nodes to a tree with tree node selection listener
<source lang="java">
import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JTree; import javax.swing.event.TreeSelectionEvent; import javax.swing.event.TreeSelectionListener; import javax.swing.tree.DefaultMutableTreeNode; import javax.swing.tree.TreeSelectionModel; public class MainClass extends JFrame {
private JTree tree1;
private JLabel showName = new JLabel();
public static void main(String[] args) {
new MainClass();
}
public MainClass() {
this.setSize(225, 325);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel1 = new JPanel();
DefaultMutableTreeNode root, a, b, c, d, e;
root = new DefaultMutableTreeNode("A");
a = makeShow("B", root);
makeShow("C", a);
makeShow("D", a);
b = makeShow("E", root);
d = makeShow("F", b);
makeShow("G", d);
e = makeShow("H", b);
makeShow("I", e);
makeShow("J", b);
makeShow("K", b);
c = makeShow("L", root);
makeShow("M", c);
makeShow("N", c);
makeShow("O", c);
tree1 = new JTree(root);
tree1.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
tree1.setVisibleRowCount(12);
tree1.addTreeSelectionListener(new TreeListener());
JScrollPane scroll = new JScrollPane(tree1);
panel1.add(scroll);
panel1.add(showName);
this.add(panel1);
this.setVisible(true);
}
private DefaultMutableTreeNode makeShow(String title, DefaultMutableTreeNode parent) {
DefaultMutableTreeNode show;
show = new DefaultMutableTreeNode(title);
parent.add(show);
return show;
}
private class TreeListener implements TreeSelectionListener {
public void valueChanged(TreeSelectionEvent e) {
Object o = tree1.getLastSelectedPathComponent();
DefaultMutableTreeNode show = (DefaultMutableTreeNode) o;
String title = (String) show.getUserObject();
showName.setText(title);
}
}
}</source>
How to Write a Tree Selection Listener
<source lang="java">
import javax.swing.JFrame; import javax.swing.JScrollPane; import javax.swing.JTree; import javax.swing.event.TreeSelectionEvent; import javax.swing.event.TreeSelectionListener; import javax.swing.tree.DefaultMutableTreeNode; import javax.swing.tree.TreeSelectionModel; public class UsingTreeSelectionListener {
public static void main(String[] a) {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JTree tree = new JTree();
tree.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
tree.addTreeSelectionListener(new SelectionListener());
frame.add(new JScrollPane(tree));
frame.setSize(300, 200);
frame.setVisible(true);
}
} class SelectionListener implements TreeSelectionListener {
public void valueChanged(TreeSelectionEvent se) {
JTree tree = (JTree) se.getSource();
DefaultMutableTreeNode selectedNode = (DefaultMutableTreeNode) tree
.getLastSelectedPathComponent();
String selectedNodeName = selectedNode.toString();
if (selectedNode.isLeaf()) {
System.out.println(selectedNodeName);
}
}
}</source>
implements TreeSelectionListener
<source lang="java">
import java.awt.BorderLayout; import javax.swing.JFrame; import javax.swing.JTree; import javax.swing.event.TreeSelectionEvent; import javax.swing.event.TreeSelectionListener; import javax.swing.tree.DefaultMutableTreeNode; import javax.swing.tree.DefaultTreeModel; import javax.swing.tree.TreeModel; import javax.swing.tree.TreeSelectionModel; public class Main extends JFrame {
public Main() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
DefaultMutableTreeNode root = new DefaultMutableTreeNode("abcde");
DefaultMutableTreeNode node = new DefaultMutableTreeNode("1");
node.add(new DefaultMutableTreeNode("12345"));
node.add(new DefaultMutableTreeNode("testing"));
root.add(node);
root.add(new DefaultMutableTreeNode("1234567890"));
TreeModel tm = new DefaultTreeModel(root);
JTree tree = new JTree(tm);
tree.getSelectionModel().addTreeSelectionListener(new Selector());
tree.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
getContentPane().add(tree, BorderLayout.CENTER);
pack();
setVisible(true);
}
private class Selector implements TreeSelectionListener {
public void valueChanged(TreeSelectionEvent event) {
Object obj = event.getNewLeadSelectionPath().getLastPathComponent();
System.out.println("" + obj.toString().length());
}
}
public static void main(String[] args) {
Main m = new Main();
}
}</source>
TreeSelectionEvent.getNewLeadSelectionPath().getLastPathComponent()
<source lang="java">
import java.awt.BorderLayout; import javax.swing.JFrame; import javax.swing.JTree; import javax.swing.event.TreeSelectionEvent; import javax.swing.event.TreeSelectionListener; import javax.swing.tree.DefaultMutableTreeNode; import javax.swing.tree.DefaultTreeModel; import javax.swing.tree.TreeModel; import javax.swing.tree.TreeSelectionModel; public class Main extends JFrame {
public Main() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
DefaultMutableTreeNode root = new DefaultMutableTreeNode("abcde");
DefaultMutableTreeNode node = new DefaultMutableTreeNode("1");
node.add(new DefaultMutableTreeNode("12345"));
node.add(new DefaultMutableTreeNode("testing"));
root.add(node);
root.add(new DefaultMutableTreeNode("1234567890"));
TreeModel tm = new DefaultTreeModel(root);
JTree tree = new JTree(tm);
tree.getSelectionModel().addTreeSelectionListener(new Selector());
tree.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
getContentPane().add(tree, BorderLayout.CENTER);
pack();
setVisible(true);
}
private class Selector implements TreeSelectionListener {
public void valueChanged(TreeSelectionEvent event) {
Object obj = event.getNewLeadSelectionPath().getLastPathComponent();
System.out.println("" + obj.toString().length());
}
}
public static void main(String[] args) {
Main m = new Main();
}
}</source>
TreeSelectionListener and TreeSelectionEvent
<source lang="java">
/*
* Copyright (c) 1995 - 2008 Sun Microsystems, Inc. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * - Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * - Neither the name of Sun Microsystems nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
/**
* 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 java.awt.Dimension; import java.awt.GridLayout; import java.io.IOException; import java.net.URL; import javax.swing.ImageIcon; 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.event.TreeSelectionEvent; import javax.swing.event.TreeSelectionListener; import javax.swing.tree.DefaultMutableTreeNode; import javax.swing.tree.DefaultTreeCellRenderer; import javax.swing.tree.TreeSelectionModel; public class TreeIconDemo extends JPanel implements TreeSelectionListener {
private JEditorPane htmlPane;
private JTree tree;
private URL helpURL;
private static boolean DEBUG = false;
public TreeIconDemo() {
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);
// Set the icon for leaf nodes.
ImageIcon leafIcon = createImageIcon("images/middle.gif");
if (leafIcon != null) {
DefaultTreeCellRenderer renderer = new DefaultTreeCellRenderer();
renderer.setLeafIcon(leafIcon);
tree.setCellRenderer(renderer);
} else {
System.err.println("Leaf 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);
}
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 = TreeIconDemo.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() {
// Create and set up the window.
JFrame frame = new JFrame("TreeIconDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Create and set up the content pane.
TreeIconDemo newContentPane = new TreeIconDemo();
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();
}
});
}
}</source>
