## java画的时钟 .

2018年01月30日 ⁄ 综合 ⁄ 共 4877字 ⁄ 字号 评论关闭

java画时钟，难点在与计算各点的坐标值，这些计算都与高中所学的几何图形有关。这里的时钟小程序，是从网上搜索到的，这里只是整理了一下。加了点注视，易于理解。

先来看下运行的结果截图：

```package com.mengke.j2se.scpture;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Insets;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.geom.Ellipse2D;
import java.awt.geom.GeneralPath;
import java.awt.geom.Line2D;
import java.awt.geom.Rectangle2D;
import java.util.Calendar;
import java.util.Date;

import javax.swing.BorderFactory;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.UIManager;

public class Clock extends JComponent {
private static final Color INTEGRAL_COLOR = new Color(0, 128, 128);
private double s = 0.03;
private Calendar currentTime = Calendar.getInstance();

}

public void setCurrentTime(Date time) {
this.currentTime.setTime(time);
}

public void setCurrentTime(long millis) {
this.currentTime.setTimeInMillis(millis);
}

public Dimension getPreferredSize() {
Insets insets = getInsets();
int r = (int) (radius == -1 ? 0 : radius * (1 + s)) + 1;
return new Dimension(r * 2 + insets.left + insets.right, r * 2 + insets.top + insets.bottom);
}

protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
//反锯齿开关开
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
Insets insets = getInsets();
int wid = getWidth() - insets.left - insets.right;
int hei = getHeight() - insets.top - insets.bottom;
int r = (int) ((Math.min(wid, hei)) / 2 / (1 + s));
g2d.translate(insets.left + r * (1 + s), insets.top + r * (1 + s));
g2d.scale(1, -1);
//画60个点
for (int i = 0; i < 60; i++) {
int angle = 90 - i * 6;
double pos[] = calcPos(r, angle);
paintMinuteDot(r, g2d, pos[0], pos[1], i % 5 == 0);
}
//画时针
paintHourPointer(r, g2d);

//画分针
paintMinutePointer(r, g2d);

//画秒针
paintSecondPointer(r, g2d);
//画中间点
paintCenterPoint(g2d);
g2d.scale(1, -1);
g2d.translate(-insets.left - r * (1 + s), -insets.top - r * (1 + s));
}

/*
* 画时钟中间那一点
* @param g2d
*/
private void paintCenterPoint(Graphics2D g2d) {
g2d.setColor(Color.BLUE);
Rectangle2D rect = new Rectangle2D.Double(-2, -2, 4, 4);
g2d.fill(rect);
}

/*
* 画分针
* @param r
* @param g2d
*/
private void paintMinutePointer(int r, Graphics2D g2d) {
int minute = currentTime.get(Calendar.MINUTE);
int second = currentTime.get(Calendar.SECOND);
double angle = 90 - (minute + second / 60.0) * 6;
Shape pointerShape = createPointerShape(r * 0.8, r * 0.04, r * 0.08, angle);
g2d.setColor(Color.LIGHT_GRAY);
g2d.fill(pointerShape);
g2d.setColor(Color.DARK_GRAY);
g2d.draw(pointerShape);
}

/*
* 画时针
* @param r
* @param g2d
*/
private void paintHourPointer(int r, Graphics2D g2d) {
int hour = currentTime.get(Calendar.HOUR);
int minute = currentTime.get(Calendar.MINUTE);
int second = currentTime.get(Calendar.SECOND);
double angle = 90 - (hour + minute / 60.0 + second / 3600.0) * 30;
Shape pointerShape = createPointerShape(r * 0.6, r * 0.06, r * 0.1, angle);
g2d.setColor(Color.LIGHT_GRAY);
g2d.fill(pointerShape);
g2d.setColor(Color.DARK_GRAY);
g2d.draw(pointerShape);
}

/*
* 创建指针路径多变形
* @param r1 从圆心到指针定点的长度
* @param r2 从圆心到指针侧边端点的距离
* @param r3 从圆心到指针尾部端点的距离
* @param angle 指针角度
* @return
*/
private Shape createPointerShape(double r1, double r2, double r3, double angle) {
GeneralPath gp = new GeneralPath();
double[] pos = calcPos(r1, angle);//指针定点
double[] pos1 = calcPos(r2, angle + 90);//指针侧边断点
gp.append(new Line2D.Double(pos[0], pos[1], pos1[0], pos1[1]), true);
double[] pos2 = calcPos(r3, angle + 180);//指针尾部
gp.lineTo((float) pos2[0], (float) pos2[1]);
double[] pos3 = calcPos(r2, angle + 270);//指针的另一侧边断点
gp.lineTo((float) pos3[0], (float) pos3[1]);
gp.closePath();
return gp;
}

/*
*画秒针
* @param r
* @param g2d
*/
private void paintSecondPointer(int r, Graphics2D g2d) {
g2d.setColor(Color.BLACK);
int second = currentTime.get(Calendar.SECOND);
int angle = 90 - second * 6;
double pos[] = calcPos(r * 0.9, angle);
double pos1[] = calcPos(r * 0.2, angle + 180);
Line2D line = new Line2D.Double(pos1[0], pos1[1], pos[0], pos[1]);
g2d.draw(line);
}

/**
* 画代表每一分钟的点。
* @param r
* @param g2d
* @param x
* @param y
* @param flag
*/
private void paintMinuteDot(int r, Graphics2D g2d, double x, double y, boolean flag) {
g2d.setColor(flag ? Color.RED : Color.BLACK);
if (flag) {
Ellipse2D rect = new Ellipse2D.Double(x - r * s, y - r * s, r * s * 2, r * s * 2);
g2d.fill(rect);
} else {
Ellipse2D rect = new Ellipse2D.Double(x - r * 0.02, y - r * 0.02, r * 0.04, r * 0.04);
g2d.fill(rect);
}
}

/*
*根据半径和角度计算点的坐标
* @param r
* @param angle
* @return
*/
private double[] calcPos(double r, double angle) {
double x = r * Math.cos(radian);
double y = r * Math.sin(radian);

return new double[] { x, y };
}

/**
* 显示界面
*/
public void showUI(){
public void run() {
while (true) {
try {
} catch (InterruptedException ex) {
ex.printStackTrace();
}
setCurrentTime(System.currentTimeMillis());
repaint();
}
}
}.start();
}
public static void main(String[] args) {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception e) {
e.printStackTrace();
}
final Clock clock = new Clock(50);
clock.showUI();
clock.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
JFrame f = new JFrame("GDI+时钟");