Java Swing 中的图形绘制仅绘制点

我目前正在开发一个程序，其中随着时间的推移而演变的某些数值变量在每次迭代中显示它们的值。这已经足够好了，但现在我想绘制一个图表来显示它们随时间的演变。 因此，我研究了在 Swing 中绘制图表的代码示例。我的最终代码如下所示：

public class Populus3 extends JPanel
{
    public static void main(String[] args) throws IOException {

        final Populus3 pop = new Populus3();

        JFrame f = new JFrame(); //where I want to plot the graph
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(new GraphingData());
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);


        frame = new JFrame("Animation Frame"); //where I'm running animation for another element of the program
        frame.add(pop, BorderLayout.CENTER);
        frame.setSize(graphSize, graphSize);
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //insert all sort of things

    }


    public void paint(Graphics g) 
    {
        super.paint(g);
        paintCell(g, 1);
        Toolkit.getDefaultToolkit().sync(); // necessary for linux users to draw  and animate image correctly
        g.dispose();
    }


      public void actionPerformed(ActionEvent e) {
        repaint();
    }



    @Override
    protected void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        for(int i = 0; i < particleType.length; i++)
            paintCell(g, i);  //a method that draws a small circle for the animation panel
    }



    public static class GraphingData extends JPanel {
        int[] data = {
            21, 14, 18, 03, 86, 88, 74, 87, 54, 77,
            61, 55, 48, 60, 49, 36, 38, 27, 20, 18
        };
        final int PAD = 20;

        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2 = (Graphics2D)g;
            g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                                RenderingHints.VALUE_ANTIALIAS_ON);
            int w = getWidth();
            int h = getHeight();
            // Draw ordinate.
            g2.draw(new Line2D.Double(PAD, PAD, PAD, h-PAD));

            // Draw abcissa.
            g2.draw(new Line2D.Double(PAD, h-PAD, w-PAD, h-PAD));
            double xInc = (double)(w - 2*PAD)/(data.length-1);
            double scale = (double)(h - 2*PAD)/getMax();
            // Mark data points.
            g2.setPaint(Color.red);
            for(int i = 0; i < data.length; i++) {
                double x = PAD + i*xInc;
                double y = h - PAD - scale*data[i];
                g2.fill(new Ellipse2D.Double(x-2, y-2, 4, 4));
            }
        }

        private int getMax() {
            int max = -Integer.MAX_VALUE;
            for(int i = 0; i < data.length; i++) {
                if(data[i] > max)
                    max = data[i];
            }
            return max;
        }
    }
}

现在，动画面板工作得很好。另一方面，图形面板......当我运行程序时，它显示一堆红点，没有线连接它们。我究竟做错了什么？

除了@Hovercraft 的有用建议之外，还可以考虑以下其他方法：

• 将积分累积到一个GeneralPath可以根据需要呈现，对于example https://stackoverflow.com/a/6697773/230513.

• 使用重复调用连接点drawLine()使用合适的坐标系，概述here https://stackoverflow.com/a/9373195/230513.

• Look at JFreeChart https://stackoverflow.com/tags/jfreechart/info.