Interface TreeWillExpandListener

All Superinterfaces:: EventListener

public interface TreeWillExpandListener extends EventListener

The listener that's notified when a tree expands or collapses a node. For further information and examples see How to Write a Tree-Will-Expand Listener, a section in The Java Tutorial.

Method Summary

Modifier and Type	Method	Description
`void`	`treeWillCollapse(TreeExpansionEvent event)`	Invoked whenever a node in the tree is about to be collapsed.
`void`	`treeWillExpand(TreeExpansionEvent event)`	Invoked whenever a node in the tree is about to be expanded.

Method Details

treeWillExpand

void treeWillExpand(TreeExpansionEvent event) throws ExpandVetoException

Invoked whenever a node in the tree is about to be expanded.

Parameters:: event - a TreeExpansionEvent containing a TreePath object for the node
Throws:: ExpandVetoException - to signify expansion has been canceled

treeWillCollapse

void treeWillCollapse(TreeExpansionEvent event) throws ExpandVetoException

Invoked whenever a node in the tree is about to be collapsed.

Parameters:: event - a TreeExpansionEvent containing a TreePath object for the node
Throws:: ExpandVetoException - to signify collapse has been canceled

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https://docs.oracle.com/en/java/javase/25/docs/api/java.desktop/javax/swing/event/TreeWillExpandListener.html