buttondemo.java

Java学习源代码检索系统免费版

//==============================================================
// ButtonDemo.java - Demonstrate buttons and check boxes
//
// Java学习源代码检索系统 Ver 1.0 20031015 免费正式版
// 版权所有: 中国IT认证实验室(www.ChinaITLab.com)
// 程序制作: ChinaITLab网校教研中心
// 主页地址: www.ChinaITLab.com    中国IT认证实验室
// 论坛地址: bbs.chinaitlab.com  
// 电子邮件: [e-mail]
//==============================================================

import javax.swing.*;
import javax.swing.border.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;

// The main program class
public class ButtonDemo 
 extends JFrame implements ActionListener {

 // GUI objects displayed in the frame window
 ButtonGroup group;            // Groups radio buttons
 JRadioButton redButton;       // First radio button
 JRadioButton whiteButton;     // Second radio button
 JRadioButton blueButton;      // Third radio button
 JPanel colorBox;              // Displays selected color
 JCheckBox showColorsButton;   // First check box
 JCheckBox exitOnCloseButton;  // Second check box
 JButton exitButton;           // Plain button

// Constructor initializes the GUI objects and panels
 public ButtonDemo() {

  // Select local system look and feel
  try {
   UIManager.setLookAndFeel(
    UIManager.getSystemLookAndFeelClassName());
//    UIManager.getCrossPlatformLookAndFeelClassName());
  } catch (Exception e) { }

  // End program when window closes
  addWindowListener(new WindowAdapter() {
   public void windowClosing(WindowEvent e) {
    System.exit(0);
   }
  });

  //==========================================================
  // Radio button panel and GUI objects
  //==========================================================

  // Create radio button panel and an inner pane
  // to help display the GUI objects neatly
  JPanel radioPane = new JPanel();
  JPanel innerRadioPane = new JPanel();
  radioPane.setBorder(
   BorderFactory.createBevelBorder(BevelBorder.RAISED));
  innerRadioPane.setLayout(
   new BoxLayout(innerRadioPane, BoxLayout.Y_AXIS));
  innerRadioPane.setBorder(
   BorderFactory.createEmptyBorder(10, 10, 10, 10));

  // Construct the radio group and its buttons
  // All button events go to the program's ActionListener
  group       = new ButtonGroup();
  redButton   = new JRadioButton("Red  ");
  whiteButton = new JRadioButton("White");
  blueButton  = new JRadioButton("Blue ");
  whiteButton.setSelected(true); // Select one button
  redButton.addActionListener(this);  // See ActionPerformed()
  whiteButton.addActionListener(this);
  blueButton.addActionListener(this);
  group.add(redButton);   // The group ensures that when one
  group.add(whiteButton); // button is selected, the previously
  group.add(blueButton);  // selected button is turned off

  // Construct a small panel for displaying the selected color
  colorBox = new JPanel();
  colorBox.setBackground(Color.white);
  colorBox.setPreferredSize(new Dimension(50, 50));

  // Add the GUI objects to the inner radio pane
  innerRadioPane.add(redButton);
  innerRadioPane.add(whiteButton);
  innerRadioPane.add(blueButton);
  innerRadioPane.add(
   Box.createRigidArea(new Dimension(0, 25)));  // Spacer
  innerRadioPane.add(colorBox);

  // Add the inner pane to the raised radio panel (left side)
  radioPane.add(innerRadioPane);

  //==========================================================
  // Check box panel and GUI objects
  //==========================================================

  // Create check box panel and an inner panel
  // for a neat appearance
  JPanel checkPane = new JPanel();
  JPanel innerCheckPane = new JPanel();
  checkPane.setBorder(
   BorderFactory.createBevelBorder(BevelBorder.RAISED));
  innerCheckPane.setLayout(
   new BoxLayout(innerCheckPane, BoxLayout.Y_AXIS));
  innerCheckPane.setBorder(
   BorderFactory.createEmptyBorder(10, 10, 10, 10));

  // Create the "show colors" check box object and
  // enable or disable the color radio buttons
  showColorsButton = new JCheckBox("Show colors");
  showColorsButton.setSelected(true);
  showColorsButton.addChangeListener(new ChangeListener() {
   public void stateChanged(ChangeEvent e) {
    boolean t = showColorsButton.isSelected();
    redButton.setEnabled(t);   // Enable or disable all 
    whiteButton.setEnabled(t); // radio buttons depending on
    blueButton.setEnabled(t);  // state of check box
   }
  });

  // Create the "exit on close" check box object and
  // enable or disable the Exit Program button
  exitOnCloseButton = new JCheckBox("Exit on close");
  exitOnCloseButton.addChangeListener(new ChangeListener() {
   public void stateChanged(ChangeEvent e) {
    boolean t = exitOnCloseButton.isSelected();
    exitButton.setEnabled(t);
   }
  });

  // Create the plain "Exit Program" button
  // and its action event listener
  exitButton = new JButton("Exit Program");
  exitButton.setEnabled(false);  // Initially disabled
  exitButton.addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent e) {
     System.exit(0);
   }
  });

  // Add the buttons to the inner pane
  innerCheckPane.add(showColorsButton);
  innerCheckPane.add(exitOnCloseButton);
  innerCheckPane.add(
   Box.createRigidArea(new Dimension(0, 50)));
  innerCheckPane.add(exitButton);

  // Add the inner pane to the raised check box panel
  checkPane.add(innerCheckPane);

  // Add the panels and GUI objects to the frame's content pane
  Container content = getContentPane();
  content.setLayout(new GridLayout(1, 3, 2, 2));
  content.add(radioPane);
  content.add(checkPane);
 }

 // Change the colorBox background color when user
 // selects a radio button.
 public void actionPerformed(ActionEvent e) {
  Color c;
  if (redButton.isSelected()) c = Color.red;
  else if (whiteButton.isSelected()) c = Color.white;
  else c = Color.blue;
  colorBox.setBackground(c);
 }

 // Main program simply constructs the ButtonDemo 
 // application object, and then sizes and shows the window
 public static void main(String[] args) {
  ButtonDemo app = new ButtonDemo();
  app.setTitle("Button and Check Box Demo");
  app.setSize(320, 240);
  app.show();
 }
}