How to Write a Tree Model Listener
By implementing a tree model listener, you can detect when the data displayed by a tree changes. You can use a tree model listener to detect when the user edits tree nodes. All notifications describe changes relative to a node in the tree. For details, read Dynamically Changing a Tree.
The Tree Model Listener API
The TreeModelListener Interface
TreeModelListener has no adapter class.
| Method | Purpose |
|---|---|
treeNodesChanged(TreeModelEvent)
| Called when one or more sibling nodes have changed in some way. |
treeNodesInserted(TreeModelEvent)
| Called after nodes have been inserted into the tree. |
treeNodesRemoved(TreeModelEvent)
| Called after nodes have been removed from the tree. |
treeStructureChanged(TreeModelEvent)
| Called after the tree's structure has drastically changed from the current node on down. This event applies to all nodes connected to this node. |
| Method | Purpose |
|---|---|
Object getSource()
(in java.util.EventObject)
| Return the object that fired the event. |
int[] getChildIndices()
| For treeNodesChanged, treeNodesInserted, and treeNodesRemoved, returns the indices of the changed, inserted, or deleted nodes, respectively. Returns nothing useful for treeStructureChanged.
|
Object[] getChildren()
| Returns the objects corresponding to the child indices. |
Object[] getPath()
| Returns the path to the parent of the changed, inserted, or deleted nodes. For treeStructureChanged, returns the path to the node beneath which the structure has changed.
|
TreePath getTreePath()
| Returns the same thing as getPath, but as a TreePath object. |
Examples that Use Tree Model Listeners
The following table lists the examples that use tree expansion listeners.
| Example | Where Described | Notes |
|---|---|---|
DynamicTreeDemo
| How to Use Trees | The DynamicTree class implements a tree model listener to detect when the user has edited a node's data. |