本文来自:小易博客专栏。转载请注明出处:http://blog.csdn.net/oldinaction
在此小易将坦克大战这个项目分为几个版本,以此对J2SE的知识进行回顾和总结,希望这样也能给刚学完J2SE的小伙伴们一点启示!
坦克大战V0.4实现功能:
1、写一个Missile类,产生一个可运动的子弹
2、让子弹可以通过按键控制发射,并且从坦克中心发射出来
3、使坦克停下来仍然能发子弹。为坦克添加炮筒,炮筒的方向会随着坦克运动方向而改变
4、能打出多发炮弹
5、解决炮弹不消亡的问题,解决坦克出界的问题
注意事项:
1、java.awt和java.util包中都有个List,所以当着两个包都使用了是,就要明确指定。
2、当写好了Missile类后,要在TankCilent中先new出来再将它画出来
3、根据“坦克打出一发子弹”这句话,来确定Tank中的方法fire,其返回值为Missle
4、让子弹可以通过按键控制发射,并且从坦克中心发射出来,如下图:
所以:
子弹中心点x坐标: x2 = x1 + w1/2 - w2/2;
子弹中心点y坐标: y2 = y1 + h1/2 - h2/2;
5、为了解决坦克停下也能打出炮弹的问题—画出炮筒,Tank类增加新的属性ptDir,炮筒的方向
6、解决炮弹不消亡的问题,步骤:加入控制炮弹生死的量bLive(Missle),当炮弹已经死去就不需要对其重画,当炮弹飞出边界就死亡,当炮弹死亡就从容器中去除。解决坦克出界的问题同样如此
7、打出多发炮弹,步骤:使用容器装炮弹,每当抬起某键就往容器中加入新的炮弹,逐一画出每一发炮弹
坦克大战V0.4源代码:
TankCilent类:
import java.awt.*;
import java.awt.event.*;
import java.util.List; //java.awt包中也有个List,所以此处要导包明确
import java.util.ArrayList;
public class TankClient extends Frame {
public static final int GAME_WIDTH = 800;
public static final int GAME_HEIGHT = 600;
Tank myTank = new Tank(50, 50 ,this);
List missiles = new ArrayList(); //定义一个集合来装子弹
Image offScreenImage = null; //定义一个屏幕后的虚拟图片
@Override
public void paint(Graphics g) {
myTank.drawTank(g);
for (int i = 0; i < missiles.size(); i++) { //遍历集合,把其中的子弹画出来
Missile m = missiles.get(i);
m.drawMissile(g);
}
g.drawString("Missile Count: " + missiles.size(), 10, 50); //用来记录missiles中子弹的个数
}
//利用双缓冲消除圆圈移动时屏幕的闪动
@Override
public void update(Graphics g) {
if (offScreenImage == null) {
offScreenImage = this.createImage(GAME_WIDTH, GAME_HEIGHT); //判断是为了避免每次重画时都给offScreenImage赋值
}
Graphics gOffScreen = offScreenImage.getGraphics(); //定义虚拟图片上的画笔gOffScreen
Color c = gOffScreen.getColor();
gOffScreen.setColor(Color.GREEN);
gOffScreen.fillRect(0, 0, GAME_WIDTH, GAME_HEIGHT); //重画背景,如果没有这句则在屏幕上会保留圆圈的移动路径
gOffScreen.setColor(c);
paint(gOffScreen); //把圆圈画到虚拟图片上
g.drawImage(offScreenImage, 0, 0, null); //再一次性把虚拟图片画到真实屏幕上,在真实屏幕上画则要用真实屏幕的画笔g
}
public void luanchFrame() {
this.setLocation(400, 300);
this.setSize(GAME_WIDTH, GAME_HEIGHT);
this.setTitle("坦克大战 - By:小易 - QQ:381740148");
this.setResizable(false); //不允许改变窗口大小
this.addWindowListener(new WindowAdapter() {
@Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
}); //添加关闭功能,此处使用匿名类比较合适
this.setBackground(Color.GREEN);
this.addKeyListener(new KeyMonitor());
setVisible(true);
new Thread(new PaintThread()).start(); //启动线程,实例化线程对象时不要忘了new Thread(Runnable对象);
}
public static void main(String[] args) {
TankClient tc = new TankClient();
tc.luanchFrame();
}
//PaintThread只为TankClient服务,所以写成内部类好些
public class PaintThread implements Runnable {
public void run() {
while (true) {
repaint(); //repaint()是TankClient或者他的父类的方法,内部类可以访问外部包装类的成员,这也是内部类的好处
try {
Thread.sleep(50); //每隔50毫秒重画一次
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
public class KeyMonitor extends KeyAdapter {
@Override
public void keyReleased(KeyEvent e) {
myTank.keyReleased(e);
}
@Override
public void keyPressed(KeyEvent e) {
myTank.keyPressed(e);
}
}
}
Tank类:
import java.awt.*;
import java.awt.event.*;
public class Tank {
public static final int XSPEED = 5; //定义常量X轴速度
public static final int YSPEED = 5;
public static final int WIDTH = 30;
public static final int HEIGHT = 30;
TankClient tc;
private int x , y; //定义变量画圆圈(坦克)时四边形左上点的x、y左边
private boolean bL = false, bU = false, bR = false, bD = false; //定义变量左上右下的按键是否被按下
enum Direction {L,LU,U,RU,R,RD,D,LD,STOP}; //定义枚举类型,值为左、左上、上、右上、右、右下、下、左下、停止
private Direction dir = Direction.STOP; //定义变量坦克的方向
private Direction ptDir = Direction.D; //定义变量坦克炮筒的方向,起初向下
public Tank(int x, int y) {
this.x = x;
this.y = y;
}
public Tank(int x, int y ,TankClient tc) {
this(x,y); //相当于调用上面的构造方法
this.tc = tc;
}
public void drawTank(Graphics g) {
Color c = g.getColor(); //取得g(以后称为画笔)的颜色
g.setColor(Color.RED);
g.fillOval(x, y, WIDTH, HEIGHT); //"画圆",利用填充一个四边形(四边形的内切圆),参数分别代表:四边形左上点的坐标X,Y,宽度,高度
g.setColor(c); //用完画笔后把画笔默认的颜色(黑色)设置回去
//根据炮筒的方向,画直线代表炮筒
switch (ptDir) {
case L:
g.drawLine(x+Tank.WIDTH/2, y+Tank.HEIGHT/2, x, y+Tank.HEIGHT/2);
break;
case LU:
g.drawLine(x+Tank.WIDTH/2, y+Tank.HEIGHT/2, x, y);
break;
case U:
g.drawLine(x+Tank.WIDTH/2, y+Tank.HEIGHT/2, x+Tank.WIDTH/2, y);
break;
case RU:
g.drawLine(x+Tank.WIDTH/2, y+Tank.HEIGHT/2, x+Tank.WIDTH, y);
break;
case R:
g.drawLine(x+Tank.WIDTH/2, y+Tank.HEIGHT/2, x+Tank.WIDTH, y+Tank.HEIGHT/2);
break;
case RD:
g.drawLine(x+Tank.WIDTH/2, y+Tank.HEIGHT/2, x+Tank.WIDTH, y+Tank.HEIGHT);
break;
case D:
g.drawLine(x+Tank.WIDTH/2, y+Tank.HEIGHT/2, x+Tank.WIDTH/2, y+Tank.HEIGHT);
break;
case LD:
g.drawLine(x+Tank.WIDTH/2, y+Tank.HEIGHT/2, x, y+Tank.HEIGHT);
break;
}
move(); //每次按键都会重画,就会调用drawTank,在这里重画坦克的此时位置
}
public void keyPressed(KeyEvent e) {
int key = e.getKeyCode(); //得到按键的虚拟码,再和下面的KeyEvent.VK_LEFT等虚拟码比较看是否是某按键
switch (key) {
case KeyEvent.VK_LEFT:
bL = true;
break;
case KeyEvent.VK_UP:
bU = true;
break;
case KeyEvent.VK_RIGHT:
bR = true;
break;
case KeyEvent.VK_DOWN:
bD = true;
break;
}
locateDraction();
if (dir != Direction.STOP) {
ptDir = dir;
}
}
public void keyReleased(KeyEvent e) {
int key = e.getKeyCode();
switch (key) {
case KeyEvent.VK_CONTROL: //按Ctrl就发射子弹调用fire方法
fire(); //只有松开Ctrl才能发出子弹
break;
case KeyEvent.VK_LEFT:
bL = false;
break;
case KeyEvent.VK_UP:
bU = false;
break;
case KeyEvent.VK_RIGHT:
bR = false;
break;
case KeyEvent.VK_DOWN:
bD = false;
break;
}
locateDraction();
}
//通过上右下的按键是否被按下判断坦克要运动的方向
void locateDraction() {
if(bL && !bU && !bR && !bD) dir =Direction.L;
else if(bL && bU && !bR && !bD) dir =Direction.LU;
else if(!bL && bU && !bR && !bD) dir =Direction.U;
else if(!bL && bU && bR && !bD) dir =Direction.RU;
else if(!bL && !bU && bR && !bD) dir =Direction.R;
else if(!bL && !bU && bR && bD) dir =Direction.RD;
else if(!bL && !bU && !bR && bD) dir =Direction.D;
else if(bL && !bU && !bR && bD) dir =Direction.LD;
else if(!bL && !bU && !bR && !bD) dir =Direction.STOP;
}
public void move() {
switch (dir) {
case L:
x -= XSPEED;
break;
case LU:
x -= XSPEED;
y -= YSPEED;
break;
case U:
y -= YSPEED;
break;
case RU:
x += XSPEED;
y -= YSPEED;
break;
case R:
x += XSPEED;
break;
case RD:
x += XSPEED;
y += YSPEED;
break;
case D:
y += YSPEED;
break;
case LD:
x -= XSPEED;
y += YSPEED;
break;
case STOP:
break;
}
//防止坦克出界
if (x < 0) x = 0;
if (y < 25) y = 25; //考虑了标题栏的高度
if (x + Tank.WIDTH > TankClient.GAME_WIDTH) x = TankClient.GAME_WIDTH - Tank.WIDTH;
if (y + Tank.HEIGHT > TankClient.GAME_HEIGHT) y = TankClient.GAME_HEIGHT - Tank.HEIGHT;
}
//坦克开火,就new一个子弹出来
private Missile fire() {
int x = this.x + Tank.WIDTH/2 - Missile.WIDTH/2; //让子弹从坦克中心打出
int y = this.y + Tank.HEIGHT/2 - Missile.HEIGHT/2;
Missile m = new Missile(x, y, ptDir , this.tc);
tc.missiles.add(m); //每new一个Missile对象就把他装到集合中
return m; //返回的m,其他地方可调用可不调用
}
}
Missile类:
import java.awt.*;
public class Missile {
public static final int XSPEED = 10;
public static final int YSPEED = 10;
public static final int WIDTH = 10;
public static final int HEIGHT = 10;
int x, y;
Tank.Direction dir;
boolean live = true; //定义一个判断子弹是否出界的变量
private TankClient tc;
public Missile(int x, int y, Tank.Direction dir) {
this.x = x;
this.y = y;
this.dir = dir;
}
public Missile(int x, int y, Tank.Direction dir, TankClient tc) {
this(x, y, dir);
this.tc = tc;
}
public void drawMissile(Graphics g) {
Color c = g.getColor();
g.setColor(Color.BLACK);
g.fillOval(x, y, WIDTH, HEIGHT);
g.setColor(c);
move();
}
private void move() {
switch (dir) {
case L:
x -= XSPEED;
break;
case LU:
x -= XSPEED;
y -= YSPEED;
break;
case U:
y -= YSPEED;
break;
case RU:
x += XSPEED;
y -= YSPEED;
break;
case R:
x += XSPEED;
break;
case RD:
x += XSPEED;
y += YSPEED;
break;
case D:
y += YSPEED;
break;
case LD:
x -= XSPEED;
y += YSPEED;
break;
}
if (x < 0 || y < 0 || x > tc.GAME_WIDTH || y > tc.GAME_HEIGHT) {
live = false;
tc.missiles.remove(this);
}
}
public boolean isLive() {
return live;
}
}
知识点回顾:
1、泛型的使用:数据类型的限定,此处数据类型指封装数据类型和类
2、MyEclipse生成get和set方法:光标处于该变量名上 - 单击右键 - Source - Generate Getters and Setters
3、生成成员变量的get和set方法的好处是可以再其他类中访问这个类的此成员变量