//: c13:Trees.java // From Thinking in Java, 2nd Edition // Available at http://www.BruceEckel.com // (c) Bruce Eckel 1999 // Copyright notice in Copyright.txt // Simple Swing tree example. Trees can be made // vastly more complex than this. import javax.swing.*; import java.awt.*; import java.awt.event.*; import javax.swing.tree.*; // Takes an array of Strings and makes the first // element a node and the rest leaves: class Branch { DefaultMutableTreeNode r; public Branch(String[] data) { r = new DefaultMutableTreeNode(data[0]); for(int i = 1; i < data.length; i++) r.add(new DefaultMutableTreeNode(data[i])); } public DefaultMutableTreeNode node() { return r; } } public class Trees extends JPanel { String[][] data = { { "Colors", "Red", "Blue", "Green" }, { "Flavors", "Tart", "Sweet", "Bland" }, { "Length", "Short", "Medium", "Long" }, { "Volume", "High", "Medium", "Low" }, { "Temperature", "High", "Medium", "Low" }, { "Intensity", "High", "Medium", "Low" }, }; static int i = 0; DefaultMutableTreeNode root, child, chosen; JTree tree; DefaultTreeModel model; public Trees() { setLayout(new BorderLayout()); root = new DefaultMutableTreeNode("root"); tree = new JTree(root); // Add it and make it take care of scrolling: add(new JScrollPane(tree), BorderLayout.CENTER); // Capture the tree's model: model =(DefaultTreeModel)tree.getModel(); JButton test = new JButton("Press me"); test.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e){ if(i < data.length) { child = new Branch(data[i++]).node(); // What's the last one you clicked? chosen = (DefaultMutableTreeNode) tree.getLastSelectedPathComponent(); if(chosen == null) chosen = root; // The model will create the // appropriate event. In response, the // tree will update itself: model.insertNodeInto(child, chosen, 0); // This puts the new node on the // currently chosen node. } } }); // Change the button's colors: test.setBackground(Color.blue); test.setForeground(Color.white); JPanel p = new JPanel(); p.add(test); add(p, BorderLayout.SOUTH); } public static void main(String args[]) { Show.inFrame(new Trees(),200,500); } } ///:~