帮忙吧，同志们，我的问题一个人都不来回答，YM呀，，时间都有二天了，

Question

这是我的代码
//Sina.java
import javax.swing.*;
import java.awt.*;
public class Sina extends JPanel  implements Runnable
{
double end_x=0.0;
double end_y=0.0;
double start_x=0.0;
double start_y=0.0;
Thread one;
public Sina()
{
one=new Thread(this);
one.start();
}
public void run()
{
while(true)
{
start_x=end_x;
start_y=end_y;
end_x+=0.01;
double end_y=Math.sin(end_x);
repaint();

}
}
public void paint(Graphics g)
{
g.setColor(Color.black);
g.drawLine((int)start_x*100,(int)start_y*100,(int)end_x*100,(int)end_y*100);
}
public static void main(String args[])
{

JFrame jf=new JFrame();
jf.getContentPane().add(new Sina());
jf.setSize(300,300);
jf.setVisible(true);
}
}

我看过帮助文档，说 repaint()方法只有在系统当前任务结束时才用，我不用线程，的确能够画出两条线（这一点我实现了）但是我要如何才能得画出正弦线，请高后指点一二/如能解决，高分谢，，

Answer 1

线程是正确的，但你的正弦线画得有些问题，你可以单步调试一下，end_x早就超出你的边界了。我把它注释掉，然后随便画条线就可以，代码在下面import javax.swing.*;
import java.awt.*;
public class Sina extends JPanel  implements Runnable
{
        double end_x=2.0;
        double end_y=2.0;
        double start_x=2.0;
        double start_y=2.0;
        int x=100;
        Thread one;
        public Sina()
        {
                one=new Thread(this);
               one.start();
        }
        public void run()
        {
                while(true)
                {
                        start_x=end_x;
                        start_y=end_y;
                        end_x+=0.01;
                        double end_y=Math.sin(end_x);
                        repaint();                }
        }
        public void paint(Graphics g)
        {
          g.setColor(Color.red);
        //  g.drawLine((int)start_x*10,(int)start_y*10,(int)end_x*10,(int)end_y*10);
          x++;
          g.drawLine(10,10,100,x);
        }
        public static void main(String args[])
        {
                JFrame jf=new JFrame();
                jf.getContentPane().add(new Sina());
                jf.setSize(500,500);
                jf.setVisible(true);
        }
}