Adding and removing nodes from a JTree

Question

I have a very basic JTree. As I am on a rush, I\'d prefer not to use TreeModel if it is not needed. I wrote a SSCCE to expose the problem:

Some

Answer 1

I don't know why you are deleting and recreating all the nodes.

Update should always be done through the model. You have a couple of choices:

Update the model directly:

DefaultTreeModel model = (DefaultTreeModel) tree.getModel();
DefaultMutableTreeNode root = (DefaultMutableTreeNode) model.getRoot();
model.insertNodeInto(new DefaultMutableTreeNode("another_child"), root, root.getChildCount());

Update the tree nodes and then notify the model:

DefaultTreeModel model = (DefaultTreeModel)tree.getModel();
DefaultMutableTreeNode root = (DefaultMutableTreeNode)model.getRoot();
root.add(new DefaultMutableTreeNode("another_child"));
model.reload(root);

The same applies for removing nodes.

The DefaultTreeModel has a removeNodeFromParent(...) which will update the model directly.

Or you can use the remove(...) method of the DefaultMutableTreeNode class. In which case you would need to do the reload().