TreeExpansionListener and TreeExpansionEvent
/*
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* are met:
*
* - Redistributions of source code must retain the above copyright
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*
* - 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.
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* 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
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* TreeExpandEventDemo.java requires no other files.
*/
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import javax.swing.BorderFactory;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTree;
import javax.swing.event.TreeExpansionEvent;
import javax.swing.event.TreeExpansionListener;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.TreeNode;
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();
}
});
}
}
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