Menus.java

//: c14:Menus.java
// Submenus, checkbox menu items, swapping menus,
// mnemonics (shortcuts) and action commands.
// <applet code=Menus width=300 height=100></applet>
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import com.bruceeckel.swing.*;

public class Menus extends JApplet {
  private String[] flavors = { 
    "Chocolate", "Strawberry", "Vanilla Fudge Swirl", 
    "Mint Chip", "Mocha Almond Fudge", "Rum Raisin",
    "Praline Cream", "Mud Pie" 
  };
  private JTextField t = new JTextField("No flavor", 30);
  private JMenuBar mb1 = new JMenuBar();
  private JMenu
    f = new JMenu("File"),
    m = new JMenu("Flavors"),
    s = new JMenu("Safety");
  // Alternative approach:
  private JCheckBoxMenuItem[] safety = {
    new JCheckBoxMenuItem("Guard"),
    new JCheckBoxMenuItem("Hide")
  };
  private JMenuItem[] file = { new JMenuItem("Open") };
  // A second menu bar to swap to:
  private JMenuBar mb2 = new JMenuBar();
  private JMenu fooBar = new JMenu("fooBar");
  private JMenuItem[] other = {
    // Adding a menu shortcut (mnemonic) is very
    // simple, but only JMenuItems can have them
    // in their constructors:
    new JMenuItem("Foo", KeyEvent.VK_F),
    new JMenuItem("Bar", KeyEvent.VK_A),
    // No shortcut:
    new JMenuItem("Baz"),
  };
  private JButton b = new JButton("Swap Menus");
  class BL implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      JMenuBar m = getJMenuBar();
      setJMenuBar(m == mb1 ? mb2 : mb1);
      validate(); // Refresh the frame
    }
  }
  class ML implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      JMenuItem target = (JMenuItem)e.getSource();
      String actionCommand = target.getActionCommand();
      if(actionCommand.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!");
      }
    }
  }
  class FL implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      JMenuItem target = (JMenuItem)e.getSource();
      t.setText(target.getText());
    }
  }
  // Alternatively, you can create a different
  // class for each different MenuItem. Then you
  // Don't have to figure out which one it is:
  class FooL implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      t.setText("Foo selected");
    }
  }
  class BarL implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      t.setText("Bar selected");
    }
  }
  class BazL implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      t.setText("Baz selected");
    }
  }
  class CMIL implements ItemListener {
    public void itemStateChanged(ItemEvent e) {
      JCheckBoxMenuItem target =
        (JCheckBoxMenuItem)e.getSource();
      String actionCommand = target.getActionCommand();
      if(actionCommand.equals("Guard"))
        t.setText("Guard the Ice Cream! " +
          "Guarding is " + target.getState());
      else if(actionCommand.equals("Hide"))
        t.setText("Hide the Ice Cream! " +
          "Is it hidden? " + target.getState());
    }
  }
  public void init() {
    ML ml = new ML();
    CMIL cmil = new CMIL();
    safety[0].setActionCommand("Guard");
    safety[0].setMnemonic(KeyEvent.VK_G);
    safety[0].addItemListener(cmil);
    safety[1].setActionCommand("Hide");
    safety[1].setMnemonic(KeyEvent.VK_H);
    safety[1].addItemListener(cmil);
    other[0].addActionListener(new FooL());
    other[1].addActionListener(new BarL());
    other[2].addActionListener(new BazL());
    FL fl = new FL();
    for(int i = 0; i < flavors.length; i++) {
      JMenuItem mi = new JMenuItem(flavors[i]);
      mi.addActionListener(fl);
      m.add(mi);
      // Add separators at intervals:
      if((i+1) % 3 == 0)
        m.addSeparator();
    }
    for(int i = 0; i < safety.length; i++)
      s.add(safety[i]);
    s.setMnemonic(KeyEvent.VK_A);
    f.add(s);
    f.setMnemonic(KeyEvent.VK_F);
    for(int i = 0; i < file.length; i++) {
      file[i].addActionListener(fl);
      f.add(file[i]);
    }
    mb1.add(f);
    mb1.add(m);
    setJMenuBar(mb1);
    t.setEditable(false);
    Container cp = getContentPane();
    cp.add(t, BorderLayout.CENTER);
    // Set up the system for swapping menus:
    b.addActionListener(new BL());
    b.setMnemonic(KeyEvent.VK_S);
    cp.add(b, BorderLayout.NORTH);
    for(int i = 0; i < other.length; i++)
      fooBar.add(other[i]);
    fooBar.setMnemonic(KeyEvent.VK_B);
    mb2.add(fooBar);
  }
  public static void main(String[] args) {
    Console.run(new Menus(), 300, 100);
  }
} ///:~