对于游戏来说,需要构建一个桌面窗体,建立MyFrame类,继承Frame类,专用用于游戏窗体的构建。在MyFrame类中建立launchFrame()方法,用于实现窗口的生成。
这三行代码分别用于设置窗体大小,位置和可见的,这三个方法继承自Frame类。
setSize(Constant.GAME_HEIGHT,Constant.GAME_WIDTH);
setLocation(100, 100);
setVisible(true);
定义内部类PaintThread继承Thread,重写Runnable接口方法run(),一直执行 repaint()函数,Thread.sleep(40)是让线程停止40ms。PaintThread().start()让线程的run()方法执行,可以实现窗口的动态更新。
new PaintThread().start();
class PaintThread extends Thread{
public void run(){
while(true){
repaint();
try {
Thread.sleep(40);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
在addWindowListener方法中定义内部类WindowAdapter,内部内重写了windowClosing()方法,用于窗体的退出(如果没有这个方法,窗体将无法退出)
addWindowListener(new WindowAdapter() {
@Override
public void windowClosing(WindowEvent e){
System.exit(0);
}
});
}
窗体构建类MyFrame 的完整代码如下:
package com.zhong.util;
import java.awt.Frame;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
public class MyFrame extends Frame {
/**
* 加载窗口
*/
public void launchFrame(){
setSize(Constant.GAME_HEIGHT,Constant.GAME_WIDTH);
setLocation(100, 100);
setVisible(true);
new PaintThread().start();
addWindowListener(new WindowAdapter() {
@Override
public void windowClosing(WindowEvent e){
System.exit(0);
}
});
}
class PaintThread extends Thread{
public void run(){
while(true){
repaint();
try {
Thread.sleep(40);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
定义常量类Constant,用于保存项目中的所有常量。代码如下:
package com.zhong.util;
/**
* 常量
* @author lenovo
*
*/
public class Constant {
public static final int GAME_WIDTH=800;
public static final int GAME_HEIGHT=800;
}
定义 GameUtil类,用于一般工具的实现。里面的 getImage(String path)方法,用于从指定地址读取图片。完整代码如下:
package com.zhong.util;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import javax.imageio.ImageIO;
/**
*
* 常用工具类
* @author Kobe Zhong
*
*/
public class GameUtil {
private GameUtil(){
}
public static Image getImage(String path){
URL url=GameUtil.class.getClassLoader().getResource(path);
BufferedImage img=null;
try {
img=ImageIO.read(url);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return img;
}
}
星球类Star是所有的星球所共有的属性。
定义星球的属性有图片(代表每种星球),坐标,宽度和长度(图片的)。代码如下:
Image img;
double x,y;
int width,height;
定义星球类的重载构造函数,代码如下:
public Star(){
}
public Star(Image img){
this.img=img;
this.width=img.getWidth(null);
this.height=img.getHeight(null);
}
public Star(Image img,double x,double y){
this(img);
this.x=x;
this.y=y;
}
public Star(String imgpath,double x,double y){
this(GameUtil.getImage(imgpath),x,y);
}
定义星球类的draw()方法,可以在窗体上画出星球的图片。代码如下:
public void draw(Graphics g){
g.drawImage(img,(int)x,(int)y,null);
}
星球类Star的完整代码如下:
package com.zhong.solar;
import java.awt.Graphics;
import java.awt.Image;
import com.zhong.util.GameUtil;
public class Star {
Image img;
double x,y;
int width,height;
public void draw(Graphics g){
g.drawImage(img,(int)x,(int)y,null);
}
public Star(){
}
public Star(Image img){
this.img=img;
this.width=img.getWidth(null);
this.height=img.getHeight(null);
}
public Star(Image img,double x,double y){
this(img);
this.x=x;
this.y=y;
}
public Star(String imgpath,double x,double y){
this(GameUtil.getImage(imgpath),x,y);
}
}
行星类Planet继承星球类Star,还拥有自己所特有的属性。
行星类包含长轴、短轴、运动速度、角度、中心恒星以及是否为卫星。属性定义代码如下:
double longAxis;//长轴
double shortAxis;//短轴
double speed;
double degree;//角度
Star center;
boolean isSattilite;
行星Planet的重载构造函数的代码如下:
public Planet(Star center,String imgpath, double longAxis,double shortAxis, double speed) {
super(GameUtil.getImage(imgpath));
this.x=center.x+longAxis;
this.y=center.y;
// this.img=GameUtil.getImage(imgpath);
this.shortAxis = shortAxis;
this.longAxis = longAxis;
this.speed = speed;
this.center = center;
}
public Planet(Star center,String imgpath, double longAxis,double shortAxis, double speed,boolean isSattlite) {
this(center, imgpath, longAxis,shortAxis,speed);
this.isSattilite=isSattlite;
}
public Planet(Image img, double x, double y) {
super(img, x, y);
// TODO Auto-generated constructor stub
}
public Planet(String imgpath, double x, double y) {
super(imgpath, x, y);
// TODO Auto-generated constructor stub
}
行星的运动是绕着恒星中心,做椭圆运动,其坐标变化的代码如下:
public void move(){
x=center.x+center.width/2+longAxis*Math.cos(degree);
y=center.y+center.height/2+shortAxis*Math.sin(degree);
degree+=speed;
}
行星运动轨迹也是椭圆,根据中心位置和长短轴的大小,画出其轨迹即可,代码如下:
public void drawTrace(Graphics g){
double ovalX,ovalY,ovalWidth,ovalHeight;
ovalWidth=longAxis*2;
ovalHeight=shortAxis*2;
ovalX=center.x+center.width/2-longAxis;
ovalY=center.y+center.height/2-shortAxis;
Color c=g.getColor();
g.setColor(Color.BLUE);
g.drawOval((int)ovalX, (int)ovalY, (int)ovalWidth, (int)ovalHeight);
}
行星在窗体上的绘制重写父类Star的draw()方法,并调用move()坐标变化方法,还有是否为卫星的判断,不是卫星就画运动轨迹。具体代码如下:
public void draw(Graphics g){
super.draw(g);
move();
if(!isSattilite){
drawTrace(g);
}
}
行星类Planet的完整代码如下所示:
package com.zhong.solar;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import com.zhong.util.GameUtil;
public class Planet extends Star{
double longAxis;//长轴
double shortAxis;//短轴
double speed;
double degree;//角度
Star center;
boolean isSattilite;
public void draw(Graphics g){
super.draw(g);
move();
if(!isSattilite){
drawTrace(g);
}
}
public void drawTrace(Graphics g){
double ovalX,ovalY,ovalWidth,ovalHeight;
ovalWidth=longAxis*2;
ovalHeight=shortAxis*2;
ovalX=center.x+center.width/2-longAxis;
ovalY=center.y+center.height/2-shortAxis;
Color c=g.getColor();
g.setColor(Color.BLUE);
g.drawOval((int)ovalX, (int)ovalY, (int)ovalWidth, (int)ovalHeight);
}
public void move(){
x=center.x+center.width/2+longAxis*Math.cos(degree);
y=center.y+center.height/2+shortAxis*Math.sin(degree);
degree+=speed;
}
public Planet(Star center,String imgpath, double longAxis,double shortAxis, double speed) {
super(GameUtil.getImage(imgpath));
this.x=center.x+longAxis;
this.y=center.y;
// this.img=GameUtil.getImage(imgpath);
this.shortAxis = shortAxis;
this.longAxis = longAxis;
this.speed = speed;
this.center = center;
}
public Planet(Star center,String imgpath, double longAxis,double shortAxis, double speed,boolean isSattlite) {
this(center, imgpath, longAxis,shortAxis,speed);
this.isSattilite=isSattlite;
}
public Planet(Image img, double x, double y) {
super(img, x, y);
// TODO Auto-generated constructor stub
}
public Planet(String imgpath, double x, double y) {
super(imgpath, x, y);
// TODO Auto-generated constructor stub
}
}
定义SolarFrame为主类,继承MyFrame。
加载背景图片,并定义太阳,地球,火星,月球的对象,并初始化。代码如下:
Image bg=GameUtil.getImage("images/bg.jpg");
Star sun=new Star("images/sun.jpg", Constant.GAME_HEIGHT/2, Constant.GAME_WIDTH/2);
Planet earth =new Planet(sun, "images/earth.jpg",100,50,0.1 ) ;
Planet mars =new Planet(sun, "images/Mars.jpg",200,130,0.2 ) ;
Planet moon=new Planet(earth, "images/moon.jpg",20,13,0.01,true);
重写paint()方法,将背景图片,太阳,地球,火星和月球的图片绘制。(注意:paint()方法为回调方法,不需要在主函数调用它,在其父类的构造方法中已经调用,根据其所在对象重写的功能具体实现)
public void paint(Graphics g){
g.drawImage(bg,0,0,null);
sun.draw(g);
earth.draw(g);
mars.draw(g);
moon.draw(g);
}
主方法中,定义SolarFrame对象,并调用它的launchFrame()方法(实现窗体的更新)。代码如下:
public static void main(String[] args) {
new SolarFrame().launchFrame();
}
package com.zhong.solar;
import java.awt.Graphics;
import java.awt.Image;
import com.zhong.util.Constant;
import com.zhong.util.GameUtil;
import com.zhong.util.MyFrame;
public class SolarFrame extends MyFrame{
Image bg=GameUtil.getImage("images/bg.jpg");
Star sun=new Star("images/sun.jpg", Constant.GAME_HEIGHT/2, Constant.GAME_WIDTH/2);
Planet earth =new Planet(sun, "images/earth.jpg",100,50,0.1 ) ;
Planet mars =new Planet(sun, "images/Mars.jpg",200,130,0.2 ) ;
Planet moon=new Planet(earth, "images/moon.jpg",20,13,0.01,true);
public void paint(Graphics g){
g.drawImage(bg,0,0,null);
sun.draw(g);
earth.draw(g);
mars.draw(g);
moon.draw(g);
}
public static void main(String[] args) {
new SolarFrame().launchFrame();
}
}