Java clock implementation

I. Core expressions

Because the hour pointer, minute pointer, and second pointer location need to be dynamically displayed, it is very important to confirm the angle of the three pointers;

X: The X coordinate of the origin where the three pointers intersect;

Y: Y coordinate of the origin where the three pointers intersect;

Hour_length, minute_length, and second_length indicate the length of the hour, minute, and second hands;

Hour, minute, and second indicate the current time, minutes, and seconds;

Hourline. X2 = x + hour_length * Math. Cos (hour * (math. PI/6)-math. PI/2 );
Hourline. y2 = Y + hour_length * Math. Sin (hour * (math. PI/6)-math. PI/2 );
Minline. X2 = x + minute_length * Math. Cos (minute * (math. PI/30)-math. PI/2 );
Minline. y2 = Y + minute_length * Math. Sin (minute * (math. PI/30)-math. PI/2 );
Secondline. X2 = x + second_length * Math. Cos (second * (math. PI/30)-math. PI/2 );
Secondline. y2 = Y + second_length * Math. Sin (second * (math. PI/30)-math. PI/2 );

Ii. How to dynamically display

In short, the screen is updated every second. Therefore, timer and timertask are used to meet the requirements and are refreshed every second;

Iii. Code

package org.Demo00;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.geom.Ellipse2D;import java.awt.geom.Line2D;import java.util.Calendar;import java.util.GregorianCalendar;import java.util.Timer;import java.util.TimerTask;import javax.swing.JFrame;import javax.swing.JPanel;public class Test5 extends JFrame {MyPanel clockPanel;Ellipse2D.Double e;int x;int y;Line2D.Double hourLine;Line2D.Double minLine;Line2D.Double secondLine;GregorianCalendar calendar;int hour;int minute;int second;public static final int X = 60;public static final int Y = 60;public static final int X_BEGIN = 10;public static final int Y_BEGIN = 10;public static final int RADIAN = 50;public Test5() {setSize(300, 400);clockPanel = new MyPanel();add(clockPanel);Timer t = new Timer();Task task = new Task();t.schedule(task, 0, 1000);}public static void main(String[] args) {Test5 t = new Test5();t.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);t.setVisible(true);}class MyPanel extends JPanel {public MyPanel() {e = new Ellipse2D.Double(X_BEGIN, Y_BEGIN, 100, 100);hourLine = new Line2D.Double(X, Y, X, Y);minLine = new Line2D.Double(X, Y, X, Y);secondLine = new Line2D.Double(X, Y, X, Y);}public void paintComponent(Graphics g) {super.paintComponent(g);Graphics2D g2 = (Graphics2D) g;g2.drawString("12", 55, 25);g2.drawString("6", 55, 105);g2.drawString("9", 15, 65);g2.drawString("3", 100, 65);g2.draw(e);g2.draw(hourLine);g2.draw(minLine);g2.draw(secondLine);}}class Task extends TimerTask {public void run() {calendar = new GregorianCalendar();hour = calendar.get(Calendar.HOUR);minute = calendar.get(Calendar.MINUTE);second = calendar.get(Calendar.SECOND);hourLine.x2 = X + 40 * Math.cos(hour * (Math.PI / 6) - Math.PI / 2);hourLine.y2 = Y + 40 * Math.sin(hour * (Math.PI / 6) - Math.PI / 2);minLine.x2 = X + 45* Math.cos(minute * (Math.PI / 30) - Math.PI / 2);minLine.y2 = Y + 45* Math.sin(minute * (Math.PI / 30) - Math.PI / 2);secondLine.x2 = X + 50* Math.cos(second * (Math.PI / 30) - Math.PI / 2);secondLine.y2 = Y + 50* Math.sin(second * (Math.PI / 30) - Math.PI / 2);repaint();}}}