MenuNew.java

//: c13:MenuNew.java
// From 'Thinking in Java, 2nd ed.' by Bruce Eckel
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
// Menu shortcuts and action commands.
// <applet code=MenuNew width=300
// height=100> </applet>
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import com.bruceeckel.swing.*;

public class MenuNew 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 = {
    // No menu shortcut:
    new JMenuItem("Open"),
    // Adding a menu shortcut is very simple:
    new JMenuItem("Exit", KeyEvent.VK_E)
  };
  // 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");
  class BL implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      JMenuBar m = getJMenuBar();
      setJMenuBar(m == mb1 ? mb2 : mb1);
      validate(); // Refresh the frame ///////// Necessary???
    }
  }
  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!");
      } else if(actionCommand.equals("Exit")) {
        // This trick won't work with applets
        // because MenuNew.this doesn't produce
        // a Window if this is a JApplet:
        //dispatchEvent(
        //  new WindowEvent(MenuNew.this, 
        //    WindowEvent.WINDOW_CLOSING));
      }
    }
  }
  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 cold? " + target.getState());
    }
  }
  public void init() {
    ML ml = new ML();
    CMIL cmil = new CMIL();
    safety[0].setActionCommand("Guard");
    safety[0].addItemListener(cmil);
    safety[1].setActionCommand("Hide");
    safety[1].addItemListener(cmil);
    file[0].setActionCommand("Open");
    file[0].addActionListener(ml);
    file[1].setActionCommand("Exit");
    file[1].addActionListener(ml);
    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]);
    f.add(s);
    for(int i = 0; i < file.length; i++)
      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());
    cp.add(b, BorderLayout.NORTH);
    for(int i = 0; i < other.length; i++)
      fooBar.add(other[i]);
    mb2.add(fooBar);
  }
  public static void main(String[] args) {
    Console.run(new MenuNew(), 300, 100);
  }
} ///:~