CODEWITHSUNDEEP
javaswingjtree
user489041
user489041

Reputation: 28312

Determine if node was deleted in JTree

Right now, I have a TreeSelectionListener on my JTree. This works fine. However, I need to detect the case that a node has been deleted. I am not sure how to do this using a TreeSelectionEvent.

I haven't seen anything in the JavaDoc about it. I was looking for something analogous to a TableModelEvent where it has a getType() method that allows you to know if something was updated,deleted, or inserted into the table. Any idea how this can be detected?

I can't use a TreeModelListener, because when I call:

((DefaultTreeModel)getModel()).removeNodeFromParent(node);

On my tree, it triggers the valueChanged(TreeSelectionEvent) to be fired. This is what I am trying to escape from.

Something like:

public void valueChanged(TreeSelectionEvent treeSelectionEvent){
    if(treeSelectionEvent.someMethod()){ <----need this
        return;
    }
}

Upvotes: 0

Views: 125

Answers (1)

copeg
copeg

Reputation: 8348

I need to detect the case that a node has been deleted

To detect that a node has been deleted, you can use a TreeModelListener. Simple example:

DefaultTreeModel model = new DefaultTreeModel(new DefaultMutableTreeNode("Root"));
JTree tree = new JTree(model);
model.addTreeModelListener(new TreeModelListener(){
    public  void treeNodesRemoved(TreeModelEvent e){
        //do something
    }
    //further listener implementation here
});

EDIT: To prevent the Selection listener from firing when deleting the node, you could

  1. Remove the selection listener
  2. Delete the node
  3. add back the selection listener

Upvotes: 3

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