randomlines.java

简单的java入门编程

 import java.awt.*;
 import java.awt.event.*;
 import javax.swing.*;
 import java.util.*;
 public class RandomLines extends JFrame
 	implements ActionListener{
 		private Random randomPositions=new Random();
 		private JButton button;
 		private JPanel panel;
 		
 		public static void main (String[] args){
 			RandomLines frame=new RandomLines();
 			frame.setSize(150,200);
 			frame.createGUI();
 			frame.show();
 			
 		}

private void createGUI(){
	setDefaultCloseOperation(EXIT_ON_CLOSE);
	Container window=getContentPane();
	window.setLayout(new FlowLayout());
	
	panel=new JPanel();
	panel.setPreferredSize(new Dimension(100,100));
	panel.setBackground(Color.white);
	window.add(panel);
	
	button =new JButton("Press me");
	window.add(button);
	button.addActionListener(this);
	
}
public void actionPerformed(ActionEvent event){
	int xEnd,yEnd;
	Graphics paper =panel.getGraphics();
	
	paper.setColor(Color.white);
	paper.fillRect(0,0,100,100);
	paper.setColor(Color.red);
	
	xEnd=randomPositions.nextInt(100);
	yEnd=randomPositions.nextInt(100);
	paper.drawLine(0,0,xEnd,yEnd);
 	}
}