Question

我试图通过使用数组定义点然后在每个时间步上用一条线连接它来“绘制”以下“随机漫步”的路径。我已经尝试了几乎所有东西，但线条根本没有画入...屏幕是空白的。任何帮助将不胜感激！显然，以下内容使用了JFrame库。我的代码如下：

import java.awt.Graphics;
import java.awt.Color;
import javax.swing.JPanel;
import javax.swing.JFrame;

public class RandomWalk extends JPanel {

public static void main(String args[]) {

    //The number of steps the algorithm iterates over.
    int num = 2000;

    //The length of a line.
    int range = 50;

    //Arrays for points.
    float[] ax = new float[num];
    float[] ay = new float[num];

    //Dimensions of the combined array.
    for (int i = 0; i < num; i++) {
        ax[i] = 768;
        ay[i] = 1280;
    }

    //Generates frame.
    JFrame frame = new JFrame();

    //Sets frame resolution and other parameters.
    frame.setSize(768,1280);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    RandomWalk panel = new RandomWalk();
    frame.add(panel);
    frame.setVisible(true);
    frame.setResizable(false);
   }

   public void paintComponent(Graphics g, int num, int range, int [] ax, int [] ay) {

   //Shift all elements 1 place to the left.
   for(int i = 1; i < num; i++) {
       ax[i-1] = ax[i];
       ay[i-1] = ay[i];
   }

   //Put a new value at the end of the array.
   ax[num-1] += (int) ((Math.random() * -range) + range);
   ay[num-1] += (int) ((Math.random() * -range) + range); 

   //Draw a line connecting the points
   for(int i=1; i<num; i++) {    
     float val = (float) ((i)/num * 204.0 + 51);
     //Sets line color black
     g.setColor(new Color((int) 0));
     g.drawLine(ax[i-1], ay[i-1], ax[i], ay[i]);
   }

   repaint();
}
}

Answer 1

试试这个

public class RandomWalk extends JPanel
{
final int   range   = 50;//max space to move in width or height
final int   num     = 50;//number of line-1 to draw
final int[] ax      = new int[num];
final int[] ay      = new int[num];

public RandomWalk(final int width, final int height)
{

    final Random rand = new Random();//better to use Random. Easier to debug since you can set a seed

    // lets set first point in the middle
    ax[0] = width / 2;
    ay[0] = height / 2;

    // generating random point
    for (int i = 1; i < num; i++)
    {
        //make sure that we dont go outside the bound of the panel
        ax[i] = (int) Math.max(0, Math.min(width, ax[i - 1] + ((rand.nextFloat() - .5f) * range)));
        ay[i] = (int) Math.max(0, Math.min(height, ay[i - 1] + ((rand.nextFloat() - .5f) * range)));
    }

}

public void paintComponent(Graphics g)
{

    g.setColor(Color.black);
    for (int i = 1; i < num; i++)
        g.drawLine((int) ax[i - 1], (int) ay[i - 1], (int) ax[i], (int) ay[i]);

}

public static void main(String[] args)
{
    // Generates frame.
    JFrame frame = new JFrame();

    // Sets frame resolution and other parameters.
    frame.setSize(300, 300);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    RandomWalk panel = new RandomWalk(frame.getWidth(), frame.getHeight());
    frame.getContentPane().add(panel);
    frame.setVisible(true);
     frame.setResizable(false);
}

}

使用数组在Java中绘制随机游走

1 个答案: