sharkattack.java

鲨鱼攻击猎物游戏 是一个Applet程序

package shark;

import javax.swing.*;
import java.awt.event.*;
import java.applet.AudioClip;
import java.awt.MediaTracker;
import java.awt.Image;
import java.awt.Graphics;

public class SharkAttack extends JApplet implements Runnable {
    private Shark shark = null; //定义鲨鱼

    private SharkPrey prey[] = null; //用数组保存猎物

    private SharkControls guide = null; //控制鲨鱼运动的面板

    private SwanCounter count = null; //猎物计数面板

    private Image river = null, aSwan = null; //背景图片和猎物图片

    private AudioClip music = null, splash = null; //背景音乐和声音

    private Thread thread = null;

    /**
     * 绘制背景图片、鲨鱼和猎物图片
     */
    private class Arena extends JPanel {
        public void paintComponent(Graphics g) {
            super.paintComponent(g);
            g.drawImage(river, 0, 0, getSize().width, getSize().height, this);
            shark.paintComponent(g);
            for (int i = 0; i < prey.length; i++) {
                if (prey[i] != null) {
                    prey[i].paintComponent(g);
                }
            }
        }
    }

    private Arena arena = new Arena();

    /**
     * 当鼠标单击时，显示控制鲨鱼运动的面板，并置于所有窗口之前
     */
    private class Clicker extends MouseAdapter {
        public void mouseClicked(MouseEvent me) {
            guide.setVisible(true);
            guide.toFront();
        }
    }

    /**
     * applet的初始化代码。加载图片和背景声音，实例化Shark类、SharkPrey类、SwanCounter类
     * 和SharkControls类，并进行版面布局。
     */
    public void init() {
        river = getImage(getDocumentBase(), "Images/river.jpg");
        aSwan = getImage(getDocumentBase(), "Images/swan.gif");
        music = getAudioClip(getDocumentBase(), "Audio/jaws.wav");
        splash = getAudioClip(getDocumentBase(), "Audio/splash.wav");
        MediaTracker tracker = new MediaTracker(this);
        tracker.addImage(river, 0);
        tracker.addImage(aSwan, 1);
        try {
            tracker.waitForAll(); //加载背景图片和猎物图片
        } catch (InterruptedException ie) {
            JOptionPane.showMessageDialog(this, "Error loading images");
        }
        shark = new Shark(this);
        prey = new SharkPrey[10];
        count = new SwanCounter(new ImageIcon(aSwan), prey.length);
        //对组件布局
        getContentPane().add("Center", new JPanelBox(arena, "Shark Attack"));
        getContentPane().add("South", count);
        guide = new SharkControls(this, shark);
        arena.setToolTipText("Click to show controls");
        arena.addMouseListener(new Clicker()); //添加事件监听器
    }

    /**
     * 当页面获得焦点时执行该方法。功能是产生一个线程并启动它，开始播放背景音乐，生成10个猎物对象。
     */
    public void start() {
        thread = new Thread(this);
        count.reset();
        thread.start(); //开始线程运行
        music.loop(); //循环播放音乐
        for (int i = 0; i < prey.length; i++) {
            prey[i] = new SharkPrey(aSwan, this);
        }
    }

    /**
     * 当页面失去焦点时执行该方法。功能是停止播放背景声音和停止计数。
     */
    public void stop() {
        music.stop();
        count.stop();
        thread = null;
    }

    public void run() {
        Thread currentThread = Thread.currentThread();
        while (thread == currentThread) {
            shark.move(); //鲨鱼移动
            //让所有猎物移动
            for (int i = 0; i < prey.length; i++) {
                if (prey[i] != null) {
                    prey[i].move();
                }
            }
            try {
                thread.sleep(200); //线程休眠200毫秒
            } catch (InterruptedException ie) {
                System.err.println("Error: " + ie);
            }
            //依次判断每个猎物是否被吃掉，如果被吃掉则作相应的处理
            for (int i = 0; i < prey.length; i++) {
                if ((prey[i] != null) && (prey[i].isEatenBy(shark))) {
                    splash.play();
                    prey[i] = null;
                    count.remove();
                    if (count.getCount() == 0) { //如果所有的猎物被吃完，则applet停止运行
                        stop();
                    }
                }
            }
            arena.repaint();
        }
    }
}