画一条箭头线

Question

谁能帮我写这个函数？
要求是画一条箭头线，线条起点是(x1,y1),终点是(x2,y2)，箭头画在终点上。public void drawArrowLine（Graphics2D g，int x1,int y1,int x2,int y2){  ...}

Answer 1

public void paint(Graphics g) {
  Arrow arrow=new Arrow();
  arrow.drawArrow(g,100,100,Math.PI/4,100,Arrow.SIDE_LEAD);
}for example ：import java.awt.*;public class Arrow {
  public static final int SIDE_LEAD=0,
                          SIDE_TRAIL=1,
                          SIDE_BOTH=2,
                          SIDE_NONE=3;
  public final double pi=Math.PI;
  
  public Arrow () { ; }  public void drawArrow(Graphics g,
                        int x,int y,
                        double theta,
                        int length,
                        int side) {
    try {
      if (length < 0) { 
        theta+=pi;
        length*=-1;
      }
      int x1,y1;
      x1=(int)Math.ceil(x + length*Math.cos(theta));
      y1=(int)Math.ceil(y - length*Math.sin(theta));
      g.drawLine(x,y,x1,y1);      switch (side) {
        case SIDE_LEAD :
          drawArrow(g,x1,y1,theta+5*pi/4,5,SIDE_NONE);
          drawArrow(g,x1,y1,theta+3*pi/4,5,SIDE_NONE);
          break;
        case SIDE_TRAIL :
          drawArrow(g,x,y,theta-pi/4,5,SIDE_NONE);
          drawArrow(g,x,y,theta+pi/4,5,SIDE_NONE);
          break;
        case SIDE_BOTH :
          drawArrow(g,x,y,theta-pi/4,5,SIDE_NONE);
          drawArrow(g,x,y,theta+pi/4,5,SIDE_NONE);
          drawArrow(g,x1,y1,theta+5*pi/4,5,SIDE_NONE);
          drawArrow(g,x1,y1,theta+3*pi/4,5,SIDE_NONE);
          break;
        case SIDE_NONE :
          break;
        default:
          throw new IllegalArgumentException();
      }
    }
    catch (IllegalArgumentException iae) {
      System.out.println("Invalid value for variable side.");
    }
  }
}

Answer 2

小弟不才。上面大哥的程序能改造成我提供的接口形式的吗？
public void drawArrowLine（Graphics2D g，int x1,int y1,int x2,int y2)谢谢！

Answer 3

呵呵。你把它就当成一个控件，继承component