lucky52.java

Java案例开发集锦,里面提供了很好的学习例子

import java.applet.*;
import java.awt.*;
import java.net.*;
import java.awt.event.*;

public class Lucky52 extends Applet implements ActionListener
{
	Panel pnlNorth=new Panel();
	MyImgPanel pnlCenter=new MyImgPanel();
	Panel pnlBottom=new Panel();
	TextField txtField=new TextField(10);
	Label label=new Label("请输入你对商品价格的估计：");
	private int truePrice=3250;
						
	public Lucky52()
	{
		super();
		this.setLayout(new BorderLayout());
		pnlNorth.add(label);
		pnlNorth.add(txtField);
		add(pnlNorth,BorderLayout.NORTH);
		add(pnlCenter,BorderLayout.CENTER);
		Button btnStart=new Button("开始游戏");
		Button btnOk=new Button("确定");
		Button btnCancel=new Button("取消");
		btnStart.setActionCommand("start");
		btnStart.addActionListener(this);
		btnOk.setActionCommand("ok");
		btnOk.addActionListener(this);
		btnCancel.setActionCommand("cancel");
		btnCancel.addActionListener(this);
		pnlBottom.add(btnStart);
		pnlBottom.add(btnOk);
		pnlBottom.add(btnCancel);
		add(pnlBottom,BorderLayout.SOUTH);
		setBackground(Color.white);
		
	}
	public void actionPerformed(ActionEvent evt)
	{
		if(evt.getActionCommand().equals("start"))
		{
			pnlCenter.initImg();
			label.setText("请输入你对商品价格的估计：");
			pnlCenter.repaint();	
		}
		else if(evt.getActionCommand().equals("ok"))
		{
			int guessPrice=0;
			try
			{
				guessPrice=Integer.parseInt(txtField.getText().trim());
				String guess=comparePrice(guessPrice);
				new MsgDlg(guess);
			}
			catch(Exception e)
			{
				e.printStackTrace();
			}
		}
		else if(evt.getActionCommand().equals("cancel"))
		{
			txtField.setText("");
		}
	}
	public String comparePrice(int guessPrice)
	{
		if(guessPrice==truePrice)
		{
			return "猜对了，恭喜你！";
		}
		else if(guessPrice>truePrice)
		{
			return "猜的价格过高，请重新猜！";
		}
		else if(guessPrice<truePrice)
		{
			return "猜的价格过低，请再加价！";
		}
		return "出错了！";
	}
	
}
class MyImgPanel extends Panel
{
	String fileName="IXUS50.jpg";
	Image myImage;
	public void initImg()
	{
        URL url=null;
        try
        {
        	url=Class.forName("Lucky52").getResource("IXUS50.jpg");
        }
        catch(Exception e){}
        myImage=getToolkit().getImage(url);
        MediaTracker myTracker=new MediaTracker(this);
        myTracker.addImage(myImage,1);
        try{
            myTracker.wait();
            myTracker.checkAll();
        }
        catch(Exception e){}
	}
	public void paint(Graphics g)
	{
		g.drawImage(myImage,135,30,55,75,this);
	}
}
class MsgDlg extends Frame implements ActionListener
{
	Label label=new Label();
	public MsgDlg(String strMsg)
	{
		super();
		setTitle("猜测结果显示");
		Panel myPanel=new Panel();
		add(myPanel);
		myPanel.add(label);
		label.setText(strMsg);
		setSize(150,100);
		setLocation(300,200);
		Button btnOk=new Button("确定");
		btnOk.addActionListener(this);
		myPanel.add(btnOk);
		show();
	}
	public void actionPerformed(ActionEvent evt)
	{
		this.dispose();
	}
}