I have a large tree and don't want to load all the nodes unless they are needed. How do I dynamically load nodes and show when a node has children (which may not be loaded yet)?
Created May 3, 2012
Jay Detwiler
The JTree has a listener that can help here. The TreeWillExpandListener notifies you with an event before the JTree displays the expansion. In particular, if your implementation of a tree model is made up of Node objects pass the willExpand to the node selected like this:
public void treeWillExpand (TreeExpansionEvent event) throws ExpandVetoException {
final TreePath path = event.getPath ();
final Node node = (Node)path.getLastPathComponent();
node.willExpand ();
}
In the same way, your TreeModel implementation can pass the call to isLeaf to the node of interest which can determine dynamically if it has children or not.
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