import static java.util.Calendar.HOUR;
import static java.util.Calendar.MILLISECOND;
import static java.util.Calendar.MINUTE;
import static java.util.Calendar.SECOND;
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.util.Calendar;
import javax.swing.ImageIcon;
import javax.swing.JPanel;

/**
 * 時鐘面板
 * 
 * @author 聽說你很會玩
 */
@SuppressWarnings("serial")
public class ClockPanel extends JPanel {
 // 3個指針的粗細
 private static final BasicStroke HOURS_POINT_WIDTH = new BasicStroke(4);
 private static final BasicStroke MINUETES_POINT_WIDTH = new BasicStroke(3);
 private static final BasicStroke SEC_POINT_WIDTH = new BasicStroke(2);
 ImageIcon background;// 背景圖片對象
 private int centerX;// 中心坐標
 private int centerY;// 中心坐標
 private final static int secLen = 60; // 指針長度
 private final static int minuesLen = 55; // 指針長度
 private final static int hoursLen = 36; // 指針長度
 
 /**
 * 構造方法
 */
 public ClockPanel() {
 setToolTipText("小鍵盤+、-調整透明度，Crtl+Shift+X退出");// 提示信息
 setOpaque(false);
 
 background = new ImageIcon(getClass().getResource("clock.jpg"));// 加載圖片
 int iconWidth = background.getIconWidth();// 獲取圖片大小
 centerX = iconWidth / 2;// 獲取圖片中間坐標
 int iconHeight = background.getIconHeight();
 centerY = iconHeight / 2;// 獲取圖片中間坐標
 setPreferredSize(new Dimension(iconWidth, iconHeight));
 }
 
 @Override
 public void paint(Graphics g) {// 重寫父類方法
 Graphics2D g2 = (Graphics2D) g;
 g2.drawImage(background.getImage(), 0, 0, this);// 繪制背景圖片
 Calendar calendar = Calendar.getInstance();// 獲取日歷對象
 int millisecond = calendar.get(MILLISECOND);// 獲取毫秒值
 int sec = calendar.get(SECOND);// 獲取秒值
 int minutes = calendar.get(MINUTE);// 獲取分值
 int hours = calendar.get(HOUR);// 獲取時值
 double secAngle = (60 - sec) * 6 - (millisecond / 150); // 秒針角度
 int minutesAngle = (60 - minutes) * 6;// 分針角度
 int hoursAngle = (12 - hours) * 360 / 12 - (minutes / 2);// 時針角度
 // 計算秒針、分針、時針指向的坐標
 int secX = (int) (secLen * Math.sin(Math.toRadians(secAngle)));// 秒針指向點的X坐標
 int secY = (int) (secLen * Math.cos(Math.toRadians(secAngle))); // 秒針指向點的Y坐標
 int minutesX = (int) (minuesLen * Math
 .sin(Math.toRadians(minutesAngle))); // 分針指向點的X坐標
 int minutesY = (int) (minuesLen * Math
 .cos(Math.toRadians(minutesAngle))); // 分針指向點的Y坐標
 int hoursX = (int) (hoursLen * Math.sin(Math.toRadians(hoursAngle))); // 時針指向點的X坐標
 int hoursY = (int) (hoursLen * Math.cos(Math.toRadians(hoursAngle))); // 時針指向點的Y坐標
 // 分別繪制時針、分針、秒針
 g2.setStroke(HOURS_POINT_WIDTH);// 設置時針的寬度
 g2.setColor(Color.BLACK);// 設置時針的顏色
 g2.drawLine(centerX, centerY, centerX - hoursX, centerY - hoursY);// 繪制時針
 g2.setStroke(MINUETES_POINT_WIDTH);// 設置分針的寬度
 if (minutesAngle != hoursAngle) // 分針、時針重疊變色
 g2.setColor(new Color(0x2F2F2F));// 設置未重疊時的顏色
 else {
 g2.setColor(Color.GREEN);// 設置重疊時的顏色
 }
 g2.drawLine(centerX, centerY, centerX - minutesX, centerY - minutesY);// 繪制分針
 g2.setStroke(SEC_POINT_WIDTH);// 設置秒針的寬度
 if (secAngle != hoursAngle && secAngle != minutesAngle)// 分針、時針、秒針重疊變色
 g2.setColor(Color.ORANGE);// 設置未重疊時的顏色
 else {
 g2.setColor(Color.GREEN);// 設置重疊時的顏色
 }
 // 繪制3個指針的中心圓和秒針
 g2.fillOval(centerX - 5, centerY - 5, 10, 10);// 繪制中心圓
 g2.drawLine(centerX, centerY, centerX - secX, centerY - secY);// 繪制秒針
 g2.drawLine(centerX + 1, centerY + 1, centerX - secX + 1, centerY
 - secY + 1);// 繪制秒針
 }
}

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

/**
 * @author 張振坤
 */
@SuppressWarnings("serial")
public class ClockFrame extends JDialog {
 private float opqua = 0.7f;
 private ClockPanel clockPanel;
 private Point fp; // 拖曳窗體之前的鼠標位置
 
 public static void main(String args[]) {
 EventQueue.invokeLater(new Runnable() {
  public void run() {
  try {
   ClockFrame frame = new ClockFrame();// 創(chuàng)建窗體對象
   frame.setVisible(true);// 顯示窗體
  } catch (Exception e) {
   e.printStackTrace();
  }
  }
 });
 }
 
 /**
 * 布局窗體的構造方法
 */
 public ClockFrame() {
 super();
 setUndecorated(true);// 取消窗體修飾
 setAlwaysOnTop(true);// 窗體置頂
 setTitle("石英鐘");// 設置窗體標題
 getContentPane().setLayout(new BorderLayout());
 setBounds(100, 30, 217, 257);
 setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
 clockPanel = new ClockPanel();// 創(chuàng)建時鐘面板
 getContentPane().add(clockPanel);
 // 為時鐘面板添加鼠標按鍵事件監(jiān)聽器
 clockPanel.addMouseListener(new MouseAdapter() {
  public void mousePressed(final MouseEvent e) {
  fp = e.getPoint();
  if (e.getButton()==MouseEvent.BUTTON3){
   System.exit(0);// 右鍵退出
  }
  }
 });
 // 在時鐘面板的鼠標拖曳事件中移動窗體
 clockPanel.addMouseMotionListener(new MouseMotionAdapter() {
  public void mouseDragged(final MouseEvent e) {
  JDialog frame = (JDialog) getRootPane().getParent();
  Point point = e.getLocationOnScreen();
  frame.setLocation(point.x - fp.x, point.y - fp.y);
  }
 });
 pack();
 
 addKeyListener(new KeyAdapter() {// 為窗體添加鍵盤事件監(jiān)聽器
  public void keyPressed(final KeyEvent e) {
  int code = e.getKeyCode();
  switch (code) {// 判斷按鍵編碼
   case KeyEvent.VK_ADD:// +符號按鍵會降低透明圖
   opqua += 0.05;
   opqua = opqua > 0.95f ? 1f : opqua;
   break;
   case KeyEvent.VK_SUBTRACT:// -符號按鍵會提升透明度
   opqua -= 0.05;
   opqua = opqua < 0.1f ? 0.1f : opqua;
   break;
  }
  // 如果按Ctrl+Shift+X組合鍵，將退出程序
  if (code == KeyEvent.VK_X
   && e.getModifiersEx() == (KeyEvent.CTRL_DOWN_MASK | KeyEvent.SHIFT_DOWN_MASK))
   System.exit(0);
  }
 });
 
 Dimension screenSize = getToolkit().getScreenSize();
 double width = screenSize.getWidth();
 int x = (int) (width - getWidth() - 30);
 setLocation(x, 30);
 
 new Thread() {// 創(chuàng)建線程對象，更新時鐘面板界面
  @Override
  public void run() {
  try {
   while (true) {
   sleep(1000);// 休眠1秒
   clockPanel.repaint();// 重新繪制時鐘面板界面
   }
  } catch (InterruptedException e) {
   e.printStackTrace();
  }
  }
 }.start();
 }
}