FileDocCategorySizeDatePackage
Menu1.javaAPI DocExample5416Mon Apr 06 18:10:22 BST 1998None

Menu1.java

//: Menu1.java
//////////////////////////////////////////////////
// Copyright (c) Bruce Eckel, 1998
// Source code file from the book "Thinking in Java"
// All rights reserved EXCEPT as allowed by the
// following statements: You can freely use this file
// for your own work (personal or commercial),
// including modifications and distribution in
// executable form only. Permission is granted to use
// this file in classroom situations, including its
// use in presentation materials, as long as the book
// "Thinking in Java" is cited as the source. 
// Except in classroom situations, you cannot copy
// and distribute this code; instead, the sole
// distribution point is http://www.BruceEckel.com 
// (and official mirror sites) where it is
// freely available. You cannot remove this
// copyright and notice. You cannot distribute
// modified versions of the source code in this
// package. You cannot use this file in printed
// media without the express permission of the
// author. Bruce Eckel makes no representation about
// the suitability of this software for any purpose.
// It is provided "as is" without express or implied
// warranty of any kind, including any implied
// warranty of merchantability, fitness for a
// particular purpose or non-infringement. The entire
// risk as to the quality and performance of the
// software is with you. Bruce Eckel and the
// publisher shall not be liable for any damages
// suffered by you or any third party as a result of
// using or distributing software. In no event will
// Bruce Eckel or the publisher be liable for any
// lost revenue, profit, or data, or for direct,
// indirect, special, consequential, incidental, or
// punitive damages, however caused and regardless of
// the theory of liability, arising out of the use of
// or inability to use software, even if Bruce Eckel
// and the publisher have been advised of the
// possibility of such damages. Should the software
// prove defective, you assume the cost of all
// necessary servicing, repair, or correction. If you
// think you've found an error, please email all
// modified files with clearly commented changes to:
// Bruce@EckelObjects.com. (Please use the same
// address for non-code errors found in the book.)
/////////////////////////////////////////////////

// Menus work only with Frames.
// Shows submenus, checkbox menu items
// and swapping menus.
import java.awt.*;

public class Menu1 extends Frame {
  String[] flavors = { "Chocolate", "Strawberry",
    "Vanilla Fudge Swirl", "Mint Chip", 
    "Mocha Almond Fudge", "Rum Raisin", 
    "Praline Cream", "Mud Pie" };
  TextField t = new TextField("No flavor", 30);
  MenuBar mb1 = new MenuBar();
  Menu f = new Menu("File");
  Menu m = new Menu("Flavors");
  Menu s = new Menu("Safety");
  // Alternative approach:
  CheckboxMenuItem[] safety = {
    new CheckboxMenuItem("Guard"),
    new CheckboxMenuItem("Hide")
  };
  MenuItem[] file = {
    new MenuItem("Open"),
    new MenuItem("Exit")
  };
  // A second menu bar to swap to:
  MenuBar mb2 = new MenuBar();
  Menu fooBar = new Menu("fooBar");
  MenuItem[] other = {
    new MenuItem("Foo"),
    new MenuItem("Bar"),
    new MenuItem("Baz"),
  };
  Button b = new Button("Swap Menus");
  public Menu1() {
    for(int i = 0; i < flavors.length; i++) {
      m.add(new MenuItem(flavors[i]));
      // 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);
    setMenuBar(mb1);
    t.setEditable(false);
    add("Center", t);
    // Set up the system for swapping menus:
    add("North", b);
    for(int i = 0; i < other.length; i++)
      fooBar.add(other[i]);
    mb2.add(fooBar);
  }
  public boolean handleEvent(Event evt) {
    if(evt.id == Event.WINDOW_DESTROY) 
      System.exit(0);
    else 
      return super.handleEvent(evt);
    return true;
  }
  public boolean action(Event evt, Object arg) {
    if(evt.target.equals(b)) {
      MenuBar m = getMenuBar();
      if(m == mb1) setMenuBar(mb2);
      else if (m == mb2) setMenuBar(mb1);
    } 
    else if(evt.target instanceof MenuItem) {
      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(evt.target.equals(file[1]))
        System.exit(0);
      // CheckboxMenuItems cannot use String 
      // matching; you must match the target:
      else if(evt.target.equals(safety[0]))
        t.setText("Guard the Ice Cream! " +
          "Guarding is " + safety[0].getState());
      else if(evt.target.equals(safety[1]))
        t.setText("Hide the Ice Cream! " +
          "Is it cold? " + safety[1].getState());
      else 
        t.setText(arg.toString());
    } 
    else 
      return super.action(evt, arg);
    return true;
  }
  public static void main(String[] args) {
    Menu1 f = new Menu1();
    f.resize(300,200);
    f.show();
  }
} ///:~