Java小程序时钟代码，请帮忙解释下代码!谢谢！
由于有些类还没学好，所以对程序的绘图不怎么明白，可以帮忙讲解下或者加点注释吗？谢谢了！
import java.awt.*;
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;
private Calendar currentTime = Calendar.getInstance();
private double s = 0.03;
public Clock(int radius)
{
this.radius = radius;
}
public void setCurrentTime(Date time) //设置当前时间
{
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); //返回一个指定宽、高的Dimension
}
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
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);
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);
}
paintHourPointer(r, g2d);
paintMinutePointer(r, g2d);
paintSecondPointer(r, g2d);
paintCenterPoint(g2d);
g2d.scale(1, -1);
g2d.translate(-insets.left - r * (1+s), -insets.top - r * (1+s));
}
private void paintCenterPoint(Graphics2D g2d)
{
g2d.setColor(Color.BLUE);
Rectangle2D rect = new Rectangle2D.Double(-2, -2, 4, 4);
g2d.fill(rect);
}
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);
}
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);
}
private Shape createPointerShape(double r1, double r2, double r3, double angle)
{
GeneralPath gp = new GeneralPath();
double[] pos = calcPos(r1, angle);
double[] pos1 = calcPos(r2, angle + 90);
gp.append(new Line2D.Double(pos[0], pos[1], pos1[0], pos1[1]), true);
double[] pos2 = calcPos(r3, angle + 180);
gp.lineTo((float)pos2[0], (float)pos2[1]);
double[] pos3 = calcPos(r2, angle + 270);
gp.lineTo((float)pos3[0], (float)pos3[1]);
gp.closePath();
return gp;
}
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);
}
private void paintMinuteDot(int r, Graphics2D g2d, double x, double y, boolean flag)
{
g2d.setColor(flag ? Color.RED : Color.BLACK);
if (flag) {
//Rectangle2D rect = new Rectangle2D.Double(
Ellipse2D rect = new Ellipse2D.Double(
x - r * s, y - r * s, r * s * 2, r * s * 2);
g2d.fill(rect);
}
else {
//Rectangle2D rect = new Rectangle2D.Double(
Ellipse2D rect = new Ellipse2D.Double(
x - r * 0.02, y - r * 0.02, r * 0.04, r * 0.04);
g2d.fill(rect);
}
}
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};
}
public static void main(String[] args)
{
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception e) {
e.printStackTrace();
}
final Clock clock = new Clock(50);
clock.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
JFrame f = new JFrame( "软件4班 3104007114 彭洪钰 ");
//f.setBounds(380,200,500,600);
f.getContentPane().add(clock, BorderLayout.CENTER);
f.pack();
f.setLocationRelativeTo(null);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);
new Thread() {
public void run()
{
while (true) {
try {
Thread.sleep(1000);
} catch (InterruptedException ex) {
ex.printStackTrace();
}
clock.setCurrentTime(System.currentTimeMillis());
clock.repaint();
}
}
}.start();
}
}
[解决办法]
这样解释是没用的
你最好结合api文档，哪个类不知道就看看。那里说的更详细
[解决办法]
不懂的地方单独拿出来问吧
[解决办法]
public void setCurrentTime(Date time) //设置当前时间
{
this.currentTime.setTime(time);
}
public void setCurrentTime(long millis)
{
this.currentTime.setTimeInMillis(millis);
}
这两个一样，就是设置时间，参数不同而已。第一个传入Date，第二个是long（java的时间基本单位就是long，其实Date里面也是通过long型来记录时间的）
下面哪个方法是得到长宽