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JTree

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

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JTree

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  1. JTree javax.swing.tree javax.swing.event

  2. ComponentsJTree and JTable • COMPONENT • Model • Selection Model • Editor • Renderer

  3. 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

  4. Parts of trees • Root • Parent • Node • Branch • Etc.

  5. JTree • The JTree class displays hierarchical data. • It displays the data vertically. • Each row has one item, called a “node.”

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

  7. TreeModel • DefaultTreeModel • TreeNode • DefaultMutableTreeNode

  8. TreeModel methods • getChild(Object parent, int index) • getChildCount (Object parent) • getIndexOfChild(Object parent, Object child) • getRoot() • isLeaf(Object node)

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

  10. 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

  11. 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");

  12. 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);

  13. Customizing a Tree's Display • Java, Windows, and Motif Look & Feel implementations

  14. Add icons to tree nodes

  15. 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());

  16. 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

  17. 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();

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