The formula that I have in my code which is causing the error is the formula that was given for the assignment

问题

//The error message I'm getting is saying "cannot find symbol- method second(double) but I feel as though I have identified everything already. (I'm clearly wrong). I think there is a problem with the formula as well but that is the code I was given for the formula. Any help would be greatly appreciated.

    import java.util.GregorianCalendar;
    import javax.swing.JComponent;
    import java.awt.geom.Ellipse2D;
    import java.awt.geom.Line2D;
    import java.awt.*;//import * Class

    public class ClockComponent extends JComponent
    {

        double hour;
        double minute;
        double second;

        public void setCurrentTime()
        { 

            GregorianCalendar calendar = new GregorianCalendar(); 


            hour = calendar.get(calendar.HOUR_OF_DAY);
            minute = calendar.get(calendar.MINUTE);
            second = calendar.get(calendar.SECOND);
        }   

        public void paintComponent(Graphics g)
        {
            Graphics2D g2 = (Graphics2D) g;

            int xCoord = 40;
            int yCoord = 25;



            Ellipse2D.Double clockFace = new Ellipse2D.Double(xCoord, yCoord, 700, 700);      
            g2.setColor(Color.black);
            g2.draw(clockFace);
            g2.fill(clockFace);



            g2.setColor(Color.red);
            Font font1 = new Font("Old English Text MT",Font.BOLD,30);
            g2.setFont(font1);
            g2.drawString("John Doe", 305, 680);



            g2.setColor(Color.yellow);
            Font font2 = new Font("Arial",Font.BOLD,30);
            g2.setFont(font2);
            g2.drawString("III", xCoord + 670, yCoord + 355);
            g2.drawString("VI", xCoord + 340, yCoord + 685);
            g2.drawString("IX", xCoord + 10, yCoord + 355);
            g2.drawString("XII", xCoord + 340, yCoord + 35);



            int xCenter = 380;
            int yCenter = 380;

            double secondHandLength;
            double minuteHandLength;
            double hourHandLength;

            double xSecond = xCenter + secondHandLength; cos(second (2*Math.PI/60));
            double ySecond = yCenter - secondHandLength; sin(second (2*Math.PI/60)); 

            double xMinute = xCenter + minuteHandLength; cos(2*Math.PI/60);
            double yMinute = yCenter - minuteHandLength; sin(2*Math.PI/60);

            double xHour = xCenter + hourHandLength; cos(2*Math.PI/60);
            double yHour = yCenter - hourHandLength; sin(2*Math.PI/60);



            g2.setColor(Color.blue);
            Line2D.Double secHand = new Line2D.Double(xCenter,yCenter,xSecond,ySecond);
            g2.setStroke(new BasicStroke(1));
            g2.draw(secHand);


            Line2D.Double minHand = new Line2D.Double(xCenter,yCenter,xMinute,yMinute);
            g2.setStroke(new BasicStroke(7));
            g2.draw(minHand);


            Line2D.Double hourHand = new Line2D.Double(xCenter,yCenter,xHour,yHour);
            g2.setStroke(new BasicStroke(13));
            g2.draw(hourHand);
        }
    }

回答1:

This probably isn't what you want:

(second (2*Math.PI/60))

Java is going to treat second as a method call, as it is immediately followed by an open-paren, with some value in it. Since that function doesn't exist, Java produces that compilation error.

If you were trying to get the product of the two, you have to explicitly provide the multiplication operator.

(second * (2*Math.PI/60))

EDIT: Now that I've had a moment to look at it, these statements also don't make sense:

double xSecond = xCenter + secondHandLength; cos(second (2*Math.PI/60));

Assuming the call to cos was valid, secondHandLength isn't defined anywhere. What's more, you're dropping the result of your calculation on the floor, which isn't what you likely intend to do. I'm not sure what a sane value would be for them, since they seem independent of the cosine of a circle, but those variables need to be defined.

回答2:

I believe you are missing a multiplication symbol in the xSecond and ySecond calculation. Should be this:

        double xSecond = xCenter + secondHandLength; cos(second * (2*Math.PI/60));
        double ySecond = yCenter - secondHandLength; sin(second * (2*Math.PI/60));

来源：https://stackoverflow.com/questions/22496035/the-formula-that-i-have-in-my-code-which-is-causing-the-error-is-the-formula-tha