JTree javax.swing.tree javax.swing.event

Components JTree 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().getLastPa thComponent());

Homework Compile and run the following java programs: – TestTree.java – SampleTreeTest.java Links to the code will be found off the class website or

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.getLastSelectedP athComponent();