1.显示任意时间时钟
2.设置三个可见性属性 分别表示时针，分针，秒针的可见性
3.一个精细的时钟
主类：StillClock
@SuppressWarnings("serial")
class DetailedClock extends JPanel {
private int hour;
private int minute;
private int second;
protected int xCenter, yCenter;
protected int clockRadius;
public DetailedClock() {
}
// Construct a clock panel
public DetailedClock(int hour, int minute, int second) {
this.hour = hour;
this.minute = minute;
this.second = second;
}
// Draw the clock
protected void paintComponent(Graphics g) {
super.paintComponent(g);
// Initialize clock parameters
clockRadius =
(int)(Math.min(getSize().width, getSize().height) * 0.9 * 0.5);
xCenter = (getSize().width) / 2;
yCenter = (getSize().height) / 2;
// Draw circle
g.setColor(Color.black);
g.drawOval(xCenter - clockRadius, yCenter - clockRadius,
2 * clockRadius, 2 * clockRadius);
// Draw second hand
if (secondHandVisible) {
int sLength = (int)(clockRadius * 0.7);
int xSecond =
(int)(xCenter + sLength * Math.sin(second * (2 * Math.PI / 60)));
int ySecond =
(int)(yCenter - sLength * Math.cos(second * (2 * Math.PI / 60)));
g.setColor(Color.red);
g.drawLine(xCenter, yCenter, xSecond, ySecond);
}
// Draw minute hand
if (minuteHandVisible) {
int mLength = (int)(clockRadius * 0.6);
int xMinute =
(int)(xCenter + mLength * Math.sin(minute * (2 * Math.PI / 60)));
int yMinute =
(int)(yCenter - mLength * Math.cos(minute * (2 * Math.PI / 60)));
g.setColor(Color.blue);
g.drawLine(xCenter, yCenter, xMinute, yMinute);
}
// Draw hour hand
if (hourHandVisible) {
int hLength = (int)(clockRadius * 0.5);
int xHour = (int)(xCenter +
hLength *
Math.sin((hour + minute / 60.0) * (2 * Math.PI / 12)));
int yHour = (int)(yCenter -
hLength *
Math.cos((hour + minute / 60.0) * (2 * Math.PI / 12)));
g.setColor(Color.black);
g.drawLine(xCenter, yCenter, xHour, yHour);
}
// Display more details on the clock
for (int i = 0; i < 60; i++) {
double percent;
if (i % 5 == 0) {
percent = 0.9;
}
else {
percent = 0.95;
}
int xOuter = (int)(xCenter +
clockRadius * Math.sin(i * (2 * Math.PI / 60)));
int yOuter = (int)(yCenter -
clockRadius * Math.cos(i * (2 * Math.PI / 60)));
int xInner = (int)(xCenter +
percent * clockRadius * Math.sin(i * (2 * Math.PI / 60)));
int yInner = (int)(yCenter -
percent * clockRadius * Math.cos(i * (2 * Math.PI / 60)));
g.drawLine(xOuter, yOuter, xInner, yInner);
}
// Display hours on the clock
g.setColor(Color.black);
for (int i = 0; i < 12; i++) {
int x = (int)(xCenter +
0.8 * clockRadius * Math.sin(i * (2 * Math.PI / 12)));
int y = (int)(yCenter -
0.8 * clockRadius * Math.cos(i * (2 * Math.PI / 12)));
g.drawString("" + ((i == 0) ? 12 : i), x, y);
}
}
/** Return hour */
public int getHour() {
return hour;
}
/** Set a new hour */
public void setHour(int hour) {
this.hour = hour;
repaint();
}
/** Return minute */
public int getMinute() {
return minute;
}
/** Set a new minute */
public void setMinute(int minute) {
this.minute = minute;
repaint();
}
/** Return second */
public int getSecond() {
return second;
}
/** Set a new second */
public void setSecond(int second) {
this.second = second;
repaint();
}
private boolean hourHandVisible = true;
private boolean minuteHandVisible = true;
private boolean secondHandVisible = true;
public boolean isHourHandVisible() {
return hourHandVisible;
}
public boolean isMinuteHandVisible() {
return hourHandVisible;
}
public boolean isSecondHandVisible() {
return secondHandVisible;
}
public void setHourHandVisible(boolean hourHandVisible) {
this.hourHandVisible = hourHandVisible;
repaint();
}
public void setMinuteHandVisible(boolean minuteHandVisible) {
this.minuteHandVisible = minuteHandVisible;
repaint();
}
public void setSecondHandVisible(boolean secondHandVisible) {
this.secondHandVisible = secondHandVisible;
repaint();
}
}
MessagePanel类
@SuppressWarnings("serial")
class MessagePanel extends JPanel {
/** The message to be displayed */
private String message = "Welcome to Java";
/** The x coordinate where the message is displayed */
private int xCoordinate = 20;
/** The y coordinate where the message is displayed */
private int yCoordinate = 20;
/** Indicate whether the message is displayed in the center */
private boolean centered;
/** The interval for moving the message horizontally
* and vertically */
private int interval = 10;
/** Construct with default properties */
public MessagePanel() {
}
/** Construct a message panel with a specified message */
public MessagePanel(String message) {
this.message = message;
}
/** Return message */
public String getMessage() {
return message;
}
/** Set a new message */
public void setMessage(String message) {
this.message = message;
repaint();
}
/** Return xCoordinator */
public int getXCoordinate() {
return xCoordinate;
}
/** Set a new xCoordinator */
public void setXCoordinate(int x) {
this.xCoordinate = x;
repaint();
}
/** Return yCoordinator */
public int getYCoordinate() {
return yCoordinate;
}
/** Set a new yCoordinator */
public void setYCoordinate(int y) {
this.yCoordinate = y;
repaint();
}
/** Return centered */
public boolean isCentered() {
return centered;
}
/** Set a new centered */
public void setCentered(boolean centered) {
this.centered = centered;
repaint();
}
/** Return interval */
public int getInterval() {
return interval;
}
/** Set a new interval */
public void setInterval(int interval) {
this.interval = interval;
repaint();
}
/** Paint the message */
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (centered) {
// Get font metrics for the current font
FontMetrics fm = g.getFontMetrics();
// Find the center location to display
int stringWidth = fm.stringWidth(message);
int stringAscent = fm.getAscent();
// Get the position of the leftmost character in the baseline
xCoordinate = getWidth() / 2 - stringWidth / 2;
yCoordinate = getHeight() / 2 + stringAscent / 2;
}
g.drawString(message, xCoordinate, yCoordinate);
}
/** Move the message left */
public void moveLeft() {
xCoordinate -= interval;
repaint();
}
/** Move the message right */
public void moveRight() {
xCoordinate += interval;
repaint();
}
/** Move the message up */
public void moveUp() {
yCoordinate -= interval;
repaint();
}
/** Move the message down */
public void moveDown() {
yCoordinate += interval;
repaint();
}
/** Override get method for preferredSize */
public Dimension getPreferredSize() {
return new Dimension(200, 30);
}
}
1.显示任意时间时钟
package chapter15_编程练习题;
import java.awt.*;
import java.util.Calendar;
import java.util.GregorianCalendar;
import javax.swing.*;
@SuppressWarnings("serial")
public class Exercise15_18 extends JFrame {
public Exercise15_18() {
setLayout(new GridLayout(1, 2));
StillClock clock1 = new StillClock(4, 20, 45);
StillClock clock2 = new StillClock(22, 46, 15);
add(clock1);
add(clock2);
}
public static void main(String[] args) {
Exercise15_18 frame = new Exercise15_18();
frame.setTitle("Exercise15_18");
frame.setSize(400, 400);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null); // Center the frame
frame.setVisible(true);
}
}
@SuppressWarnings("serial")
class StillClock extends JPanel {
private int hour;
private int minute;
private int second;
/** Construct a default clock with the current time */
public StillClock() {
setCurrentTime();
}
/** Construct a clock with specified hour, minute, and second */
public StillClock(int hour, int minute, int second) {
this.hour = hour;
this.minute = minute;
this.second = second;
}
/** Return hour */
public int getHour() {
return hour;
}
/** Set a new hour */
public void setHour(int hour) {
this.hour = hour;
repaint();
}
/** Return minute */
public int getMinute() {
return minute;
}
/** Set a new minute */
public void setMinute(int minute) {
this.minute = minute;
repaint();
}
/** Return second */
public int getSecond() {
return second;
}
/** Set a new second */
public void setSecond(int second) {
this.second = second;
repaint();
}
/** Draw the clock */
protected void paintComponent(Graphics g) {
super.paintComponent(g);
// Initialize clock parameters
int clockRadius = (int) (Math.min(getWidth(), getHeight()) * 0.8 * 0.5);
int xCenter = getWidth() / 2;
int yCenter = getHeight() / 2;
// Draw circle
g.setColor(Color.black);
g.drawOval(xCenter - clockRadius, yCenter - clockRadius,
2 * clockRadius, 2 * clockRadius);
g.drawString("12", xCenter - 5, yCenter - clockRadius + 12);
g.drawString("9", xCenter - clockRadius + 3, yCenter + 5);
g.drawString("3", xCenter + clockRadius - 10, yCenter + 3);
g.drawString("6", xCenter - 3, yCenter + clockRadius - 3);
// Draw second hand
int sLength = (int) (clockRadius * 0.8);
int xSecond = (int) (xCenter + sLength
* Math.sin(second * (2 * Math.PI / 60)));
int ySecond = (int) (yCenter - sLength
* Math.cos(second * (2 * Math.PI / 60)));
g.setColor(Color.red);
g.drawLine(xCenter, yCenter, xSecond, ySecond);
// Draw minute hand
int mLength = (int) (clockRadius * 0.65);
int xMinute = (int) (xCenter + mLength
* Math.sin(minute * (2 * Math.PI / 60)));
int yMinute = (int) (yCenter - mLength
* Math.cos(minute * (2 * Math.PI / 60)));
g.setColor(Color.blue);
g.drawLine(xCenter, yCenter, xMinute, yMinute);
// Draw hour hand
int hLength = (int) (clockRadius * 0.5);
int xHour = (int) (xCenter + hLength
* Math.sin((hour % 12 + minute / 60.0) * (2 * Math.PI / 12)));
int yHour = (int) (yCenter - hLength
* Math.cos((hour % 12 + minute / 60.0) * (2 * Math.PI / 12)));
g.setColor(Color.BLACK);
g.drawLine(xCenter, yCenter, xHour, yHour);
}
public void setCurrentTime() {
// Construct a calendar for the current date and time
Calendar calendar = new GregorianCalendar();
// Set current hour, minute and second
this.hour = calendar.get(Calendar.HOUR_OF_DAY);
this.minute = calendar.get(Calendar.MINUTE);
this.second = calendar.get(Calendar.SECOND);
}
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}
2.设置三个可见性属性 分别表示时针，分针，秒针的可见性
package chapter15_编程练习题;
import javax.swing.*;
import java.awt.*;
import java.util.Calendar;
import java.util.GregorianCalendar;
@SuppressWarnings("serial")
public class Exercise15_19 extends JFrame {
public Exercise15_19() {
StillClock2 clock = new StillClock2();
clock.setSecondHandVisible(false);
clock.setHour((int)(Math.random() * 12));
clock.setMinute((int)(Math.random() * 2) == 0 ? 0 : 30);
add(clock);
}
public static void main(String[] args) {
Exercise15_19 frame = new Exercise15_19();
frame.setSize(400, 400);
frame.setTitle("Exercise15_19");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null); // Center the frame
frame.setVisible(true);
}
}
@SuppressWarnings("serial")
class StillClock2 extends JPanel {
private int hour;
private int minute;
private int second;
/** Construct a default clock with the current time */
public StillClock2() {
setCurrentTime();
}
/** Construct a clock with specified hour, minute, and second */
public StillClock2(int hour, int minute, int second) {
this.hour = hour;
this.minute = minute;
this.second = second;
}
/** Return hour */
public int getHour() {
return hour;
}
/** Set a new hour */
public void setHour(int hour) {
this.hour = hour;
repaint();
}
/** Return minute */
public int getMinute() {
return minute;
}
/** Set a new minute */
public void setMinute(int minute) {
this.minute = minute;
repaint();
}
/** Return second */
public int getSecond() {
return second;
}
/** Set a new second */
public void setSecond(int second) {
this.second = second;
repaint();
}
/** Draw the clock */
protected void paintComponent(Graphics g) {
super.paintComponent(g);
// Initialize clock parameters
int clockRadius = (int) (Math.min(getWidth(), getHeight()) * 0.8 * 0.5);
int xCenter = getWidth() / 2;
int yCenter = getHeight() / 2;
// Draw circle
g.setColor(Color.black);
g.drawOval(xCenter - clockRadius, yCenter - clockRadius,
2 * clockRadius, 2 * clockRadius);
g.drawString("12", xCenter - 5, yCenter - clockRadius + 12);
g.drawString("9", xCenter - clockRadius + 3, yCenter + 5);
g.drawString("3", xCenter + clockRadius - 10, yCenter + 3);
g.drawString("6", xCenter - 3, yCenter + clockRadius - 3);
// Draw second hand
if(secondHandVisible){
int sLength = (int) (clockRadius * 0.8);
int xSecond = (int) (xCenter + sLength
* Math.sin(second * (2 * Math.PI / 60)));
int ySecond = (int) (yCenter - sLength
* Math.cos(second * (2 * Math.PI / 60)));
g.setColor(Color.red);
g.drawLine(xCenter, yCenter, xSecond, ySecond);
}
// Draw minute hand
if(minuteHandVisible){
int mLength = (int) (clockRadius * 0.65);
int xMinute = (int) (xCenter + mLength
* Math.sin(minute * (2 * Math.PI / 60)));
int yMinute = (int) (yCenter - mLength
* Math.cos(minute * (2 * Math.PI / 60)));
g.setColor(Color.blue);
g.drawLine(xCenter, yCenter, xMinute, yMinute);
}
// Draw hour hand
if(hourHandVisible){
int hLength = (int) (clockRadius * 0.5);
int xHour = (int) (xCenter + hLength
* Math.sin((hour % 12 + minute / 60.0) * (2 * Math.PI / 12)));
int yHour = (int) (yCenter - hLength
* Math.cos((hour % 12 + minute / 60.0) * (2 * Math.PI / 12)));
g.setColor(Color.BLACK);
g.drawLine(xCenter, yCenter, xHour, yHour);
}
}
public void setCurrentTime() {
// Construct a calendar for the current date and time
Calendar calendar = new GregorianCalendar();
// Set current hour, minute and second
this.hour = calendar.get(Calendar.HOUR_OF_DAY);
this.minute = calendar.get(Calendar.MINUTE);
this.second = calendar.get(Calendar.SECOND);
}
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
private boolean hourHandVisible = true;
private boolean minuteHandVisible = true;
private boolean secondHandVisible = true;
public boolean isHourHandVisible() {
return hourHandVisible;
}
public void setHourHandVisible(boolean hourHandVisible) {
this.hourHandVisible = hourHandVisible;
repaint();
}
public boolean isMinuteHandVisible() {
return minuteHandVisible;
}
public void setMinuteHandVisible(boolean minuteHandVisible) {
this.minuteHandVisible = minuteHandVisible;
repaint();
}
public boolean isSecondHandVisible() {
return secondHandVisible;
}
public void setSecondHandVisible(boolean secondHandVisible) {
this.secondHandVisible = secondHandVisible;
repaint();
}
}
3.一个精细的时钟
package chapter15_编程练习题;
import java.awt.*;
import javax.swing.*;
@SuppressWarnings("serial")
public class Exercise15_20 extends JFrame {
public static void main(String[] args) {
// Obtain the total seconds since the midnight, Jan 1, 1970
long totalSeconds = System.currentTimeMillis() / 1000;
// Compute the current second in the minute in the hour
int currentSecond = (int)(totalSeconds % 60);
// Obtain the total minutes
long totalMinutes = totalSeconds / 60;
// Compute the current minute in the hour
int currentMinute = (int)(totalMinutes % 60);
// Obtain the total hours
long totalHours = totalMinutes / 60;
// Compute the current hour
int currentHour = (int)(totalHours % 24);
// Create a frame to hold the clock
Exercise15_20 frame = new Exercise15_20();
frame.setTitle("Exercise15_20");
DetailedClock clock = new DetailedClock(currentHour, currentMinute, currentSecond);
clock.setSecondHandVisible(false);
frame.add(clock);
MessagePanel messagePanel = new MessagePanel(
currentHour + ":" + currentMinute + ":" + currentSecond + " GMT");
messagePanel.setCentered(true);
messagePanel.setForeground(Color.blue);
frame.add(messagePanel, BorderLayout.SOUTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 350);
frame.setLocationRelativeTo(null); // Center the frame
frame.setVisible(true);
}
}
@SuppressWarnings("serial")
class DetailedClock extends JPanel {
private int hour;
private int minute;
private int second;
protected int xCenter, yCenter;
protected int clockRadius;
public DetailedClock() {
}
// Construct a clock panel
public DetailedClock(int hour, int minute, int second) {
this.hour = hour;
this.minute = minute;
this.second = second;
}
// Draw the clock
protected void paintComponent(Graphics g) {
super.paintComponent(g);
// Initialize clock parameters
clockRadius =
(int)(Math.min(getSize().width, getSize().height) * 0.9 * 0.5);
xCenter = (getSize().width) / 2;
yCenter = (getSize().height) / 2;
// Draw circle
g.setColor(Color.black);
g.drawOval(xCenter - clockRadius, yCenter - clockRadius,
2 * clockRadius, 2 * clockRadius);
// Draw second hand
if (secondHandVisible) {
int sLength = (int)(clockRadius * 0.7);
int xSecond =
(int)(xCenter + sLength * Math.sin(second * (2 * Math.PI / 60)));
int ySecond =
(int)(yCenter - sLength * Math.cos(second * (2 * Math.PI / 60)));
g.setColor(Color.red);
g.drawLine(xCenter, yCenter, xSecond, ySecond);
}
// Draw minute hand
if (minuteHandVisible) {
int mLength = (int)(clockRadius * 0.6);
int xMinute =
(int)(xCenter + mLength * Math.sin(minute * (2 * Math.PI / 60)));
int yMinute =
(int)(yCenter - mLength * Math.cos(minute * (2 * Math.PI / 60)));
g.setColor(Color.blue);
g.drawLine(xCenter, yCenter, xMinute, yMinute);
}
// Draw hour hand
if (hourHandVisible) {
int hLength = (int)(clockRadius * 0.5);
int xHour = (int)(xCenter +
hLength *
Math.sin((hour + minute / 60.0) * (2 * Math.PI / 12)));
int yHour = (int)(yCenter -
hLength *
Math.cos((hour + minute / 60.0) * (2 * Math.PI / 12)));
g.setColor(Color.black);
g.drawLine(xCenter, yCenter, xHour, yHour);
}
// Display more details on the clock
for (int i = 0; i < 60; i++) {
double percent;
if (i % 5 == 0) {
percent = 0.9;
}
else {
percent = 0.95;
}
int xOuter = (int)(xCenter +
clockRadius * Math.sin(i * (2 * Math.PI / 60)));
int yOuter = (int)(yCenter -
clockRadius * Math.cos(i * (2 * Math.PI / 60)));
int xInner = (int)(xCenter +
percent * clockRadius * Math.sin(i * (2 * Math.PI / 60)));
int yInner = (int)(yCenter -
percent * clockRadius * Math.cos(i * (2 * Math.PI / 60)));
g.drawLine(xOuter, yOuter, xInner, yInner);
}
// Display hours on the clock
g.setColor(Color.black);
for (int i = 0; i < 12; i++) {
int x = (int)(xCenter +
0.8 * clockRadius * Math.sin(i * (2 * Math.PI / 12)));
int y = (int)(yCenter -
0.8 * clockRadius * Math.cos(i * (2 * Math.PI / 12)));
g.drawString("" + ((i == 0) ? 12 : i), x, y);
}
}
/** Return hour */
public int getHour() {
return hour;
}
/** Set a new hour */
public void setHour(int hour) {
this.hour = hour;
repaint();
}
/** Return minute */
public int getMinute() {
return minute;
}
/** Set a new minute */
public void setMinute(int minute) {
this.minute = minute;
repaint();
}
/** Return second */
public int getSecond() {
return second;
}
/** Set a new second */
public void setSecond(int second) {
this.second = second;
repaint();
}
private boolean hourHandVisible = true;
private boolean minuteHandVisible = true;
private boolean secondHandVisible = true;
public boolean isHourHandVisible() {
return hourHandVisible;
}
public boolean isMinuteHandVisible() {
return hourHandVisible;
}
public boolean isSecondHandVisible() {
return secondHandVisible;
}
public void setHourHandVisible(boolean hourHandVisible) {
this.hourHandVisible = hourHandVisible;
repaint();
}
public void setMinuteHandVisible(boolean minuteHandVisible) {
this.minuteHandVisible = minuteHandVisible;
repaint();
}
public void setSecondHandVisible(boolean secondHandVisible) {
this.secondHandVisible = secondHandVisible;
repaint();
}
}
@SuppressWarnings("serial")
class MessagePanel extends JPanel {
/** The message to be displayed */
private String message = "Welcome to Java";
/** The x coordinate where the message is displayed */
private int xCoordinate = 20;
/** The y coordinate where the message is displayed */
private int yCoordinate = 20;
/** Indicate whether the message is displayed in the center */
private boolean centered;
/** The interval for moving the message horizontally
* and vertically */
private int interval = 10;
/** Construct with default properties */
public MessagePanel() {
}
/** Construct a message panel with a specified message */
public MessagePanel(String message) {
this.message = message;
}
/** Return message */
public String getMessage() {
return message;
}
/** Set a new message */
public void setMessage(String message) {
this.message = message;
repaint();
}
/** Return xCoordinator */
public int getXCoordinate() {
return xCoordinate;
}
/** Set a new xCoordinator */
public void setXCoordinate(int x) {
this.xCoordinate = x;
repaint();
}
/** Return yCoordinator */
public int getYCoordinate() {
return yCoordinate;
}
/** Set a new yCoordinator */
public void setYCoordinate(int y) {
this.yCoordinate = y;
repaint();
}
/** Return centered */
public boolean isCentered() {
return centered;
}
/** Set a new centered */
public void setCentered(boolean centered) {
this.centered = centered;
repaint();
}
/** Return interval */
public int getInterval() {
return interval;
}
/** Set a new interval */
public void setInterval(int interval) {
this.interval = interval;
repaint();
}
/** Paint the message */
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (centered) {
// Get font metrics for the current font
FontMetrics fm = g.getFontMetrics();
// Find the center location to display
int stringWidth = fm.stringWidth(message);
int stringAscent = fm.getAscent();
// Get the position of the leftmost character in the baseline
xCoordinate = getWidth() / 2 - stringWidth / 2;
yCoordinate = getHeight() / 2 + stringAscent / 2;
}
g.drawString(message, xCoordinate, yCoordinate);
}
/** Move the message left */
public void moveLeft() {
xCoordinate -= interval;
repaint();
}
/** Move the message right */
public void moveRight() {
xCoordinate += interval;
repaint();
}
/** Move the message up */
public void moveUp() {
yCoordinate -= interval;
repaint();
}
/** Move the message down */
public void moveDown() {
yCoordinate += interval;
repaint();
}
/** Override get method for preferredSize */
public Dimension getPreferredSize() {
return new Dimension(200, 30);
}
}
时间： 2024-12-27 05:39:44