Expansion and Collapse Events in a JTree are fired before a node is expanded or collapsed can be vetoed, thereby preventing the operation. : Tree « Swing JFC « Java

1. Java
2. Swing JFC
3. Tree

Expansion and Collapse Events in a JTree are fired before a node is expanded or collapsed can be vetoed, thereby preventing the operation.

    

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.event.TreeExpansionEvent;
import javax.swing.event.TreeExpansionListener;
import javax.swing.event.TreeWillExpandListener;
import javax.swing.tree.ExpandVetoException;
import javax.swing.tree.TreePath;

public class Main {
  public static void main() {
    JTree tree = new JTree();
    tree.addTreeWillExpandListener(new MyTreeWillExpandListener());
    tree.addTreeExpansionListener(new MyTreeExpansionListener());

    JFrame f = new JFrame();
    f.add(new JScrollPane(tree));
    f.setSize(300, 300);
    f.setVisible(true);

  }
}

class MyTreeWillExpandListener implements TreeWillExpandListener {
  public void treeWillExpand(TreeExpansionEvent evt) throws ExpandVetoException {
    JTree tree = (JTree) evt.getSource();

    TreePath path = evt.getPath();
    boolean veto = false;
    if (veto) {
      throw new ExpandVetoException(evt);
    }
  }

  public void treeWillCollapse(TreeExpansionEvent evt) throws ExpandVetoException {
    JTree tree = (JTree) evt.getSource();

    TreePath path = evt.getPath();
    boolean veto = false;
    if (veto) {
      throw new ExpandVetoException(evt);
    }
  }
}

class MyTreeExpansionListener implements TreeExpansionListener {
  public void treeExpanded(TreeExpansionEvent evt) {
    JTree tree = (JTree) evt.getSource();

    TreePath path = evt.getPath();
    System.out.println("treeExpanded");
  }

  public void treeCollapsed(TreeExpansionEvent evt) {
    JTree tree = (JTree) evt.getSource();

    TreePath path = evt.getPath();
    System.out.println("treeCollapsed");
  }
}

   
    
    
    
  

Related examples in the same category

1.	Build a tree based on DefaultMutableTreeNode
2.	Add Tree to JScrollPane
3.	Genealogy Tree
4.	Tree Lines
5.	DefaultMutableTreeNode Node Tree Sample
6.	Display a file system in a JTree view
7.	implements TreeSelectionListener to create your own listener
8.	File folder Tree with icons
9.	File Tree with Popup Menu
10.	File Tree with Tooltips
11.	Ancestor Tree with Icons
12.	Tree Icon Demo
13.	DefaultMutableTreeNode and user object
14.	Display user object in a tree
15.	Tree Expand Event Demo
16.	Tree: Drag and Drop
17.	Tree open Icon
18.	Traverse Tree
19.	Tree based on Array structure
20.	Tree will Expand event and listener
21.	Set the Tree Line
22.	Tree Selection Row
23.	JTree.DynamicUtilTreeNode.createChildren
24.	Install ToolTips for Tree (JTree)
25.	Tree Expand Event Demo 2
26.	A tree with component
27.	A sample component for dragging and dropping a collection of files into a tree.
28.	DnD (drag and drop)JTree code
29.	Build a tree and populate it from hashtables
30.	A simple test to see how we can build a tree and populate it
31.	Installs custom icons
32.	Build a tree and customize its icons
33.	Displaying Hierarchical Data within a JTree
34.	Add and remove tree Node and expand the tree node
35.	File System Tree
36.	TreeExpansionListener and TreeExpansionEvent
37.	Enabling and Disabling Multiple Selections in a JTree Component
38.	Allow only a single node to be selected (default)
39.	Allow selection to span one vertical contiguous set of visible nodes
40.	Allow multiple selections of visible nodes
41.	Setting the Row Height of a JTree
42.	All rows will be given 15 pixels of height
43.	Have the row height for each row computed individually
44.	Flush the internal cache of Row height
45.	Preventing Expansion or Collapse of a Node in a JTree: override JTree.setExpandedState()
46.	Removing a Node to a JTree Component
47.	JTree root cannot be removed with removeNodeFromParent(), use DefaultTreeModel.setRoot() to remove the root
48.	Listening for Expansion and Collapse Events in a JTree Component
49.	Creating a JTree Component
50.	Changing and Removing the Default Icons in a JTree Component
51.	Use UIManager to change the default icon for JTree
52.	Getting the Selected Nodes in a JTree Component
53.	Visiting All the Nodes in a JTree Component
54.	Traverse all expanded nodes in tree
55.	Finding a Node in a JTree Component
56.	Search backward from last visible row looking for any visible node whose name starts with prefix.
57.	Find the path regardless of visibility that matches the specified sequence of names
58.	Adding a Node to a JTree Component
59.	Returns a TreePath containing the specified node.
60.	Converting All Nodes in a JTree Component to a TreePath Array
61.	Get path for all expanded or not expanded tree pathes
62.	Expanding or Collapsing All Nodes in a JTree Component
63.	Preventing the Expansion or Collapse of a Node in a JTree Component
64.	Listening for Selection Events in a JTree Component
65.	Have a popup attached to a JTree
66.	Deleting nodes from JTree
67.	Adding editable nodes to JTree
68.	Searching node in a JTree
69.	Drag and drop of a group of files into a tree
70.	JTree drag and drop utilites
71.	Expand All for a tree path
72.	Get tree path from TreeNode
73.	JTree Utilities
74.	Expand JTree