🚀 go-pugleaf

On 7/24/2004 at 10:21:42 PM, Ramon F Herrera wrote:

> However, I don't know what event should trigger the above
> response.  The only Tree Listener seems to be 'valueChanged'
> which is fired only when one of the folders is clicked.
> 
> How can I detect a click on the background of a tree??

JTree is derived from JComponent and Component, so it inherits all of
their methods.  If you check Component, you will find the
addMouseListener() method.

You will need to add a MouseListener and respond to one of the MouseEvents
(mousePressed, mouseReleased, mouseClicked), and determine if the mouse
position is pointing to one of the JTree's nodes.  I think you should be
able to use the JTree getRowForLocation() method to do that.

-- 
Regards,

John McGrath [TeamB]

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Ramon F Herrera wrote:
> 
> I have a problem with JTrees: the user can click away
> selecting a set of paths (with the usual <shift> and
> <control> keys) but there is no click method that will
> restore the tree to its original, pristine, unselected
> state.
> 
> What I would like to implement is the familiar Mac and
> Windows icon selection: when the user clicks on the
> desktop all the file icons become unselected.
> 
> I figured out how to perform the actual unselection:
> 
>     rightTree.setSelectionPath(null);
> 
> However, I don't know what event should trigger the above
> response.  The only Tree Listener seems to be 'valueChanged'
> which is fired only when one of the folders is clicked.
> 
> How can I detect a click on the background of a tree??

Examine the snippet below.


------------TreeDemo.java------------

import java.awt.BorderLayout;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

import javax.swing.JFrame;
import javax.swing.JTree;
import javax.swing.event.TreeExpansionEvent;
import javax.swing.event.TreeWillExpandListener;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.TreePath;

public class TreeDemo extends JFrame implements MouseListener,
         TreeWillExpandListener {
     JTree tree;

     boolean isExpanding = false;

     public TreeDemo() {
         super();

         DefaultMutableTreeNode nodeRoot = new 
DefaultMutableTreeNode("Folder1");
         DefaultMutableTreeNode nodeFolder1 = new DefaultMutableTreeNode(
                 "Folder1");
         DefaultMutableTreeNode nodeFolder2 = new DefaultMutableTreeNode(
                 "Folder2");
         DefaultMutableTreeNode nodeItem1 = new 
DefaultMutableTreeNode("Item1");
         nodeRoot.add(nodeFolder1);
         nodeFolder1.add(nodeFolder2);
         nodeFolder2.add(nodeItem1);
         tree = new JTree(nodeRoot);
         tree.addMouseListener(this);
         tree.addTreeWillExpandListener(this);

         this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         this.setSize(300, 300);
         this.getContentPane().setLayout(new BorderLayout());
         this.getContentPane().add(BorderLayout.CENTER, tree);
         this.setVisible(true);

     }

     public static void main(String[] args) {
         new TreeDemo();
     }

     public void mouseClicked(MouseEvent e) {
         if (e.getSource().equals(tree)) {
             TreePath path = tree.getPathForLocation(e.getX(), e.getY());
             if (path != null) {
                 DefaultMutableTreeNode clickedNode = 
(DefaultMutableTreeNode) path
                         .getLastPathComponent();
                 System.out.println(clickedNode.toString());
             } else {
                 if (!isExpanding) {
                     tree.clearSelection();
                 }
             }
             isExpanding = false;
         }
     }

     public void mouseEntered(MouseEvent e) {
     }

     public void mouseExited(MouseEvent e) {
     }

     public void mousePressed(MouseEvent e) {
     }

     public void mouseReleased(MouseEvent e) {
     }

     public void treeWillCollapse(TreeExpansionEvent event) {
         isExpanding = true;
     }

     public void treeWillExpand(TreeExpansionEvent event) {
         isExpanding = true;
     }

}

------------------------------------------------

     --Stephan.