java画的时钟

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：

界面还是比较好看的。

下面贴出代码：

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 int radius;//半径 private double s = 0.03; private Calendar currentTime = Calendar.getInstance(); public Clock(int radius) { this.radius = radius; } 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 radian = Math.toRadians(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(){ new Thread() { public void run() { while (true) { try { Thread.sleep(1000); } 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”); f.add(clock, BorderLayout.CENTER); f.pack(); f.setLocationRelativeTo(null); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setVisible(true); } }