文章来源：J2ME开发网
笔者以前是做j2ee的，一个月前由于兴趣所致开始利用业余时间学习j2me游戏开发。在网上看了一通教程
下面是游戏中所需要的部分图片，还有的图片下次写到了再上传：
hero_left.png:
hero_right.png:
hero_up.png:
hero_down.png:
整个程序的主体在BraveCanvas类中完成，该类继承于GameCanvas实现Runnable接口，由BraveMIDlet类启
动他，BraveMIDlet继承MIDlet实现CommandListener接口。BraveMIDlet类代码如下：（由于只是一个简单的rpg，开头画面和菜单全部省略了，改为由一个按扭启动游戏）
BraveMIDlet.java
package brave;
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
public class BraveMIDlet extends MIDlet implements CommandListener
{
private Display d ;
private Command exitCommand ;
private Command startCommand ;
private BraveCanvas braveCanvas;
public BraveMIDlet()
{
d = Display.getDisplay(this);
exitCommand = new Command("退出",Command.EXIT,1);
startCommand = new Command("开始",Command.SCREEN,1);
}
public void startApp()
{
//创建BraveCanvas
braveCanvas = new BraveCanvas();
braveCanvas.addCommand(exitCommand);
braveCanvas.addCommand(startCommand);
braveCanvas.setCommandListener(this);
//装载BraveCanvas
d.setCurrent(braveCanvas);
}
public void pauseApp()
{
}
public void destroyApp(boolean unconditional)
{
}
public void commandAction(Command c , Displayable dpa)
{
String str_co = c.getLabel();
if(str_co.equals("开始"))
{
//运行BraveCanvas中的线程（启动游戏）
braveCanvas.startup();
}
else if(str_co.equals("退出"))
{
destroyApp(false);
notifyDestroyed();
}
}
}
BraveCanvas.java
package brave;
import javax.microedition.lcdui.game.GameCanvas;
import javax.microedition.lcdui.Graphics;
import java.io.IOException;
public class BraveCanvas extends GameCanvas implements Runnable
{
private boolean sign;
private Graphics g;
//设置@符号的当前位置
private int x,y;
public BraveCanvas()
{
super(true);
//初始化@位置
x = getWidth()/2;
y = getHeight()/2;
}
public void startup()
{
this.sign = true;
Thread thread = new Thread(this);
//启动线程
thread.start();
}
public void run()
{
g = getGraphics();
while(sign)
{
try
{
//@符号的移动
input(g);
//@符号的显示
paint(g);
//这里应该有详细的计算，方便为上，置为15
Thread.sleep(15);
}
catch(Exception e)
{
System.out.println("2:"+e);
}
}
}
public void input(Graphics g) throws IOException
{
int keystates = getKeyStates();
switch(keystates)
{
case UP_PRESSED:
y = Math.max(0, y - 1);
break;
case DOWN_PRESSED:
y = Math.min(getHeight(), y + 1);
break;
case LEFT_PRESSED:
x = Math.max(0, x - 1);
break;
case RIGHT_PRESSED:
x = Math.min(getWidth(), x + 1);
break;
}
}
public void paint(Graphics g)
{
//设置画布的背景色
g.setColor(0x000000);
//把背景色画满画布
g.fillRect(0, 0, getWidth(), getHeight());
//设置画布的前景色
g.setColor(0xffffff);
//在画布上写上@
g.drawString("@", x, y, Graphics.TOP|Graphics.LEFT);
//刷新画布
flushGraphics();
}
}
上面代码运行后，画面上会出现一个"@"字符随着键盘的左右而移动。虽然这离rpg游戏相差很远，但这是一
个游戏的基本框架。下面我们要做的就是把"@"换成我们的英雄。为了程序清晰，我们还要设计一个英雄类
Hero，该类继承于Sprite，这个类里面要用到上面的图片。
Hero.java
package brave;
import javax.microedition.lcdui.game.Sprite;
import javax.microedition.lcdui.Image;
import java.io.IOException;
public class Hero extends Sprite
{
//设置英雄的当前位置
private int x, y;
private BraveCanvas braveCanvas;
public Hero(Image image, int frameWidth, int frameHeight)
{
//英雄的初始化
super(image, frameWidth, frameHeight);
}
public void setBraveCanvas(BraveCanvas braveCanvas)
{
this.braveCanvas = braveCanvas;
}
public void init(int x, int y)
{
//英雄位置的初始化
this.x = x;
this.y = y;
}
public void afresh()
{
//刷新英雄的位置
setPosition(this.x, this.y);
}
public void moveUp() throws IOException
{
//英雄上移，并改为相应的图片
setImage(Image.createImage("/hero_up.png"), 17, 26);
nextFrame();
this.y = Math.max(0, y - 1);
}
public void moveDown() throws IOException
{
//英雄下移，并改为相应的图片
setImage(Image.createImage("/hero_down.png"), 17, 26);
nextFrame();
this.y = Math.min(braveCanvas.getHeight(), y + 1);
}
public void moveLeft() throws IOException
{
//英雄左移，并改为相应的图片
setImage(Image.createImage("/hero_left.png"), 17, 26);
nextFrame();
this.x = Math.max(0, x - 1);
}
public void moveRight() throws IOException
{
//英雄右移，并改为相应的图片
setImage(Image.createImage("/hero_right.png"), 17, 26);
nextFrame();
this.x = Math.min(braveCanvas.getWidth(), x + 1);
}
}
然后把BraveCanvas类稍做修改，把"@"换成英雄
BraveCanvas.java
package brave;
import javax.microedition.lcdui.game.GameCanvas;
import javax.microedition.lcdui.Graphics;
import java.io.IOException;
import javax.microedition.lcdui.Image;
public class BraveCanvas extends GameCanvas implements Runnable
{
private boolean sign;
private Graphics g;
private Hero hero;
public BraveCanvas()
{
super(true);
}
public void startup()
{
this.sign = true;
try
{
Image heroimage = Image.createImage("/hero_up.png");
hero = new Hero(heroimage, 17, 26);
hero.setBraveCanvas(this);
hero.init(40,40);
}
catch(Exception e)
{
e.printStackTrace();
}
Thread thread = new Thread(this);
thread.start();
}
public void run()
{
g = getGraphics();
while(sign)
{
try
{
input(g);
paint(g);
Thread.sleep(15);
}
catch(Exception e)
{
System.out.println("2:"+e);
}
}
}
public void input(Graphics g) throws IOException
{
int keystates = getKeyStates();
switch(keystates)
{
case UP_PRESSED:
hero.moveUp();
break;
case DOWN_PRESSED:
hero.moveDown();
break;
case LEFT_PRESSED:
hero.moveLeft();
break;
case RIGHT_PRESSED:
hero.moveRight();
break;
}
hero.afresh();
}
public void paint(Graphics g)
{
g.setColor(0x000000);
g.fillRect(0, 0, getWidth(), getHeight());
g.setColor(0xffffff);
hero.paint(g);
flushGraphics();
}
}
这样，我们的英雄就可以在画面上移动了，不过英雄比较简单，没有hp,mp等等，只是一个图片。而且如果大
家感觉英雄的脚步过快，可以在BraveCanvas类中的Hero初始化时设置：
hero.setFrameSequence(new int[]{0, 0, 1, 1, 0, 0, 2, 2 });
暂时先写到这，在下次中我会把地图和碰撞检测加入。由于本人也是初学者，上面的代码有什么不妥的地方，请高手兄们多多赐教。msn：zhagy_1981@hotmail.com
