ball.java

分子无规则运动演示

import java.awt.*;
import javax.swing.*;

public class Ball
{
	private int xpos;
	private int ypos;
	private int diameter=30;
	private int dx=10;
	private int dy=10;
	
	private JPanel panel;
	
	private Color color=Color.black;
	
	public Ball()
	{
	}
	public Ball(int x,int y,JPanel panel)
	{
		xpos=x;
		ypos=y;
		this.panel=panel;
		dx=(int)(Math.random()*31);
		dy=(int)(Math.random()*31);
		int sgnx=(int)(Math.random()*2);
		int sgny=(int)(Math.random()*2);
		
		if(sgnx==0)
			dx=-dx;
		if(sgny==0)
			dy=-dy;
	}
	
	public void drawBall(Graphics g)
	{
		g.fillOval(xpos,ypos,diameter,diameter);
	}
	
	public void motion()
	{
		xpos+=dx;
		ypos+=dy;
		if(xpos<0)
		{
			xpos=0;
			dx=-dx;
		}
		if(xpos>panel.getWidth()-diameter)
		{
			xpos=panel.getWidth()-diameter;
			dx=-dx;
		}
		if(ypos<0)
		{
			ypos=0;
			dy=-dy;
		}
		if(ypos>panel.getHeight()-diameter)
		{
			ypos=panel.getHeight()-diameter;
			dy=-dy;
		}
		
		panel.repaint();
		
	}

	
	public void setXpos(int xpos) {
		this.xpos = xpos; 
	}

	public void setYpos(int ypos) {
		this.ypos = ypos; 
	}

	public void setDiameter(int diameter) {
		this.diameter = diameter; 
	}

	public void setDx(int dx) {
		this.dx = dx; 
	}

	public void setDy(int dy) {
		this.dy = dy; 
	}

	public void setPanel(JPanel panel) {
		this.panel = panel; 
	}

	public void setColor(Color color) {
		this.color = color; 
	}

	public int getXpos() {
		return (this.xpos); 
	}

	public int getYpos() {
		return (this.ypos); 
	}

	public int getDiameter() {
		return (this.diameter); 
	}

	public int getDx() {
		return (this.dx); 
	}

	public int getDy() {
		return (this.dy); 
	}

	public JPanel getPanel() {
		return (this.panel); 
	}

	public Color getColor() {
		return (this.color); 
	}
}