//: c13:Menu1.java // From 'Thinking in Java, 2nd ed.' by Bruce Eckel // www.BruceEckel.com. See copyright notice in CopyRight.txt. // Shows submenus, checkbox menu // items, and swapping menus // <applet code=Menu1 // width=300 height=100> </applet> import javax.swing.*; import java.awt.*; import java.awt.event.*; import com.bruceeckel.swing.*; public class Menu1 extends JApplet { String[] flavors = { "Chocolate", "Strawberry", "Vanilla Fudge Swirl", "Mint Chip", "Mocha Almond Fudge", "Rum Raisin", "Praline Cream", "Mud Pie" }; JTextField t = new JTextField("No flavor", 30); JMenuBar mb1 = new JMenuBar(); JMenu f = new JMenu("File"), m = new JMenu("Flavors"), s = new JMenu("Safety"); // Alternative approach: JCheckBoxMenuItem[] safety = { new JCheckBoxMenuItem("Guard"), new JCheckBoxMenuItem("Hide") }; JMenuItem[] file = { new JMenuItem("Open"), new JMenuItem("Exit") }; // A second menu bar to swap to: JMenuBar mb2 = new JMenuBar(); JMenu fooBar = new JMenu("fooBar"); JMenuItem[] other = { new JMenuItem("Foo"), new JMenuItem("Bar"), new JMenuItem("Baz"), }; JButton b = new JButton("Swap Menus"); public void init() { for(int i = 0; i < flavors.length; i++) { JMenuItem mi = new JMenuItem(flavors[i]); mi.addActionListener(al); m.add(mi); // Add separators at intervals: if((i+1) % 3 == 0) m.addSeparator(); } for(int i = 0; i < safety.length; i++) { safety[i].addActionListener(al); s.add(safety[i]); } f.add(s); for(int i = 0; i < file.length; i++) { file[i].addActionListener(al); f.add(file[i]); } mb1.add(f); mb1.add(m); t.setEditable(false); Container cp = getContentPane(); cp.add(t, BorderLayout.CENTER); // Set up the system for swapping menus: b.addActionListener(al); cp.add(b, BorderLayout.NORTH); for(int i = 0; i < other.length; i++) { other[i].addActionListener(al); fooBar.add(other[i]); } mb2.add(fooBar); setJMenuBar(mb1); } ActionListener al = new ActionListener() { public void actionPerformed(ActionEvent e) { String arg = e.getActionCommand(); Object source = e.getSource(); if(source.equals(b)) { JMenuBar m = getJMenuBar(); setJMenuBar(m == mb1 ? mb2 : mb1); validate(); // Refresh the frame } else if(source instanceof JMenuItem) { if(arg.equals("Open")) { String s = t.getText(); boolean chosen = false; for(int i = 0; i < flavors.length; i++) if(s.equals(flavors[i])) chosen = true; if(!chosen) t.setText("Choose a flavor first!"); else t.setText("Opening "+s+". Mmm, mm!"); } else if(source.equals(file[1])) System.exit(0); // CheckboxMenuItems cannot use String // matching; you must match getSource(): else if(source.equals(safety[0])) t.setText("Guard the Ice Cream! " + "Guarding is "+safety[0].getState()); else if(source.equals(safety[1])) t.setText("Hide the Ice Cream! " + "Is it cold? "+safety[1].getState()); else t.setText(arg); } } }; public static void main(String[] args) { Console.run(new Menu1(), 300, 100); } } ///:~