JTree

javax.swing.tree

javax.swing.event

ComponentsJTree and JTable

COMPONENT– Model– Selection Model– Editor – Renderer

JTree

Tree model– describes a JTree’s underlying data model. It

specifies how a tree is mapped over a data structure.

Tree selection Tree cell editor Tree cell renderer

Parts of trees

Root Parent Node Branch Etc.

JTree

The JTree class displays hierarchical data.

It displays the data vertically.

Each row has one item, called a “node.”

DefaultTreeModel

Is a simple implementation of Tree Model that uses TreeNodes objects to hold items in the tree.

TreeModel– DefaultTreeModel

TreeNode– DefaultMutableTreeNode

TreeModel methods

getChild(Object parent, int index) getChildCount (Object parent) getIndexOfChild(Object parent, Object child) getRoot() isLeaf(Object node)

DefaultMutableTreeNode

There is a rich set of methods in the DefaultMutableTreeNode class for viewing and manipulating nodes in a tree.

DefaultMutableTreeNode methods Tree enumeration

preorderEnumeration()– Conducts a preorder traversal rooted at this node

and returns an enumeration of TreeNode objects

postorderEnumeration()– Conducts a postorder traversal rooted at this node

and returns and enumeration of TreeNode objects

JTree sample code

DefaultMutableTreeNode root = new DefaultMutableTreeNode("Root");

DefaultMutableTreeNode subroot = new DefaultMutableTreeNode("Subroot");

DefaultMutableTreeNode leaf1 = new DefaultMutableTreeNode("Leaf 1");

DefaultMutableTreeNode leaf2 = new

DefaultMutableTreeNode("Leaf 2");

Quick JTree code

treeModel = new DefaultTreeModel(root); tree = new JTree(treeModel); treeModel.insertNodeInto(subroot, root, 0); treeModel.insertNodeInto(leaf1, subroot, 0); treeModel.insertNodeInto(leaf2, root, 1);

Customizing a Tree's Display

Java, Windows, and Motif Look & Feel implementations

Add icons to tree nodes

Dynamically Changing a Tree

tree = new JTree(treeModel); tree.setEditable(true); treeModel.addTreeModelListener(new

MyTreeModelListener()); ... class MyTreeModelListener implements TreeModelListener

{ public void treeNodesChanged(TreeModelEvent e) { DefaultMutableTreeNode node; node = (DefaultMutableTreeNode)

(e.getTreePath().getLastPathComponent());

Homework

Compile and run the following java programs:– TestTree.java– SampleTreeTest.java

Links to the code will be found off the class website or

http://my.fit.edu/~ghrezo/TestTree.java.htm

http://my.fit.edu/~ghrezo/SampleTreeTest.java.htm

Tree node selection(tree listeners)

tree.getSelectionModel().setSelectionMode (TreeSelectionModel.SINGLE_TREE_SELECTION);

//Listen for when the selection changes. tree.addTreeSelectionListener(new TreeSelectionListener() {

public void valueChanged(TreeSelectionEvent e) { DefaultMutableTreeNode node = (DefaultMutableTreeNode)tree.getLastSelectedPathComponent();