e5_11.java

来自「java 初学者学习实例」· Java 代码 · 共 71 行

import java.awt.*;
import java.applet.*;
import java.awt.event.*;
class Mycanvas extends Canvas {
	int x,y;
	Mycanvas(int a,int b)
	{
		x=a;y=b;
		getSize();
	}
	public void paint (Graphics g)
	{
		g.setColor(Color.red);
		g.fillOval(50,50,4*x,4*y);
	//	g.drawString("我在画布上写字呢！",6,30);
		g.drawString("我是第 "+x,20,90);
	}
	public Dimension  PreferredSize()
	{
		return new Dimension(200,100);
	}

}
public class E5_11 extends Applet implements ActionListener
{
	CardLayout mycard;
	Button button1,button2,button3;
	Mycanvas mycanvas[];
	Panel p;
	Panel p2;
	public void init()
	{
		setLayout(new BorderLayout());
		mycard = new CardLayout();
		p = new Panel();
		p.setLayout(mycard);
		button1 = new Button("First"); 
		button2 = new Button("Next");
		button3 = new Button("Last One");
		mycanvas = new Mycanvas[21];
		for (int i=1;i<20;i++)
		{
			mycanvas[i] = new Mycanvas(i,i);
			p.add("I am "+i,mycanvas[i]);
			
		}  
		button1.addActionListener(this);
		button2.addActionListener(this);
		button3.addActionListener(this);
		p2 = new Panel();
		p2.add(button1);p2.add(button2);p2.add(button3);
		add(p,"Center");add(p2,"South");
	}
	public void actionPerformed(ActionEvent e)
	{
		if(e.getSource()==button1)
		{
			mycard.first(p);
		}
		else if(e.getSource()==button2)
		{
			mycard.next(p);
		}
		else if(e.getSource()==button3)
		{
			mycard.last(p);
		}
		
	}
}