JTree

[Alan Brooks]

Hello,

I have been making a dynamic JTree but when i delet a node it disapears from the tree but when i click to expand the new tree the node that has been removed reapers. Can anyone help me so that when i remove the node it does not come back when i try expand the tree.

   

	public void populateTree() {
		DefaultMutableTreeNode subFolder = null;
		File SubDir;

		for (int a = 0; a < getNumberOfUsers(); a++) {
			removed = false;
			int count = 0;
			subFolder = new DefaultMutableTreeNode(getUser(a).getName());
			SubDir = getUser(a);
			// treePanel.addObject(null, SubDir.getName());
			treeModel.insertNodeInto(subFolder, rootNode, rootNode
					.getChildCount());
			for (int b = 0; b < getNumberOfRemovedUsers(); b++){
				if (getUser(a).getName().equals(getRemovedUsers(b))){
					treeModel.removeNodeFromParent(subFolder);
				//treeModel.reload(rootNode);
			}
			}

		}
		treeModel.setRoot(rootNode);
		treeModel.reload(rootNode);
	}
 

I am using

   

	protected DefaultMutableTreeNode rootNode;
	protected DefaultTreeModel treeModel;
	protected JTree tree;
 

[Andre Uhres]

Each time, before calling populateTree(), we should initialize again "rootNode" and "treeModel" and set the "treeModel" to the tree:

rootNode = new DefaultMutableTreeNode("Root");
treeModel = new DefaultTreeModel(rootNode);
tree.setModel(treeModel);
populateTree();

[Alan Brooks]

This is being done already and does not help

[Andre Uhres]

Alan Brooks wrote:This is being done already and does not help

Could you please post a short independant and compilable example?

[Alan Brooks]

Hey managed to get the JTree to update I was not redrawing it the correct way. I have one last question. If you use a treeModel is there anyway to rename the node after it has been inserted.

[Gregg Bolinger]

Alan Brooks wrote:Hey managed to get the JTree to update I was not redrawing it the correct way. I have one last question. If you use a treeModel is there anyway to rename the node after it has been inserted.

I noticed you are passing the name of the User object to the constructor of DefaultMutableTreeNode. This works, however, for renaming and IMO best practice dictates that you specify a custom User Object in the constructor of your node. The node will then use the toString method of your object for the node label.

subFolder = new DefaultMutableTreeNode(getUser(a));

And then assuming User's toString returns getName(), you're good. Anytime you want access to this object you can simple do:

User user = (User)node.getUserObject();

Then changing the name of 'user' will change the name of the nodes label.

[Andre Uhres]

Gregg Bolinger wrote:Then changing the name of 'user' will change the name of the nodes label.

To refresh the GUI we also need to call nodeChanged:
defaultTreeModel.nodeChanged(node);

[Alan Brooks]

treeModel.insertNodeInto(subFolder, rootNode, rootNode.getChildCount());
				subFolder = new DefaultMutableTreeNode(getUser(a).getSurName());
				treeModel.nodeChanged(subFolder); 

I know this is still not IMO best practice but is doing this the values in the Jtree do not chnage, do you know were i am going wrong