使用 Jbulider 开发 J2ME 移动游戏程序

作者使用JBuilder2005，里面自带WTK2.1，自己下载2.2版本，2.2那个默认的模拟器看着实在爽。另外，Jbuilder X下的WTK也是2.0的版本。Jbuilder 9的WTK是1.04。首先开启Jbuilder。建立一个Project：

然后填写名字和路径。继续：

然后选择JDK路径，本身已有WTK2.1，你可以选择。但是你也可以自己选择其他的WTK版本:

点击jdk后面的路径按钮,继续:

next.工程建立完毕。接着点击file->New:

然后在对话框左边选择Micro，你就能看到右边出现MIDlet，Displayable。接上面的:如图示

点击MIDlet or Displayable,则让你输入MIDlet的名字.如图:

继续下一步，让你输入一个Displayable的名字，包括类型(form,canvas等)，是否自动加载Command等等。

然后Jbuilder自动生成所需代码,以及Jbuilder自加的一些东西。你可以添加或修改之。这里我将本站一篇关于介绍Gamecanvas的文章的代码拿过来,做少量修改,作为本文章的一个演示：

TestMIDlet.java文件:

package temps;

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

/**
 * <p>Title: </p>
 *
 * <p>Description: </p>
 *
 * <p>Copyright: Copyright (c) 2005</p>
 *
 * <p>Company: </p>
 *
 * @author not attributable
 * @version 1.0
 */
public class TestMIDlet extends MIDlet
{
    private Display display;

    public void startApp()
    {
        try
        {
            display = Display.getDisplay(this);
            Displayable1 gameCanvas = new Displayable1();
            gameCanvas.start();
            display.setCurrent(gameCanvas);
        }
        catch (Exception ex)
        {
            System.out.println(ex);
        }
    }

    public Display getDisplay()
    {
        return display;
    }

    public void pauseApp()
    {
    }

    public void destroyApp(boolean unconditional)
    {
        exit();
    }

    public void exit()
    {
        System.gc();
        destroyApp(false);
        notifyDestroyed();
    }
}


Displayable1.java内容:

package temps;

import javax.microedition.lcdui.*;
import java.util.Random;
import javax.microedition.lcdui.game.*;
/**
 * <p>Title: </p>
 *
 * <p>Description: </p>
 *
 * <p>Copyright: Copyright (c) 2005</p>
 *
 * <p>Company: </p>
 *
 * @author not attributable
 * @version 1.0
 */
public class Displayable1 extends GameCanvas implements Runnable
{
    private boolean isPlay; // Game Loop runs when isPlay is true
    private long delay; // To give thread consistency
    private int currentX, currentY; // To hold current position of the 'X'
    private int width; // To hold screen width
    private int height; // To hold screen height
    private Random random=new Random(System.currentTimeMillis());
    private final int[] sequence={0,1,2,1,0,1,2,1,0,1,2,1,1,1,1,1,1};
    private int counter=0;
    private int enemyX,enemyY;
    private int enemyDirect=0;
    private boolean isdown=false;

    private boolean isalive=true;

    // Sprites to be used
    private Sprite playerSprite;
    private Sprite backgroundSprite;
    private Sprite enemySprite;

    // Layer Manager
    private LayerManager layerManager;

    // Constructor and initialization
    public Displayable1() throws Exception
    {
        super(true);
        width = getWidth();
        height = getHeight();

        currentX = width / 2;
        currentY = height / 2;
        enemyX=width/4;
        enemyY=height/4;
        delay = 100;

        Image playerImage=null;
        Image backgroundImage=null;
        Image enemy=null;
        // Load Images to Sprites
        try
        {
            playerImage = Image.createImage("/transparent.png");
            backgroundImage = Image.createImage("/background.png");
            enemy=Image.createImage("/frames.png");
        }
        catch(Exception e)
        {
            System.out.println("get Image error!"+e.getMessage());
        }

        playerSprite = new Sprite(playerImage, 32, 32);
        System.out.println(playerSprite.getRawFrameCount());
        enemySprite=new Sprite(enemy,50,21);
        backgroundSprite = new Sprite(backgroundImage);
        layerManager = new LayerManager();
        layerManager.append(playerSprite);
        layerManager.append(enemySprite);
        layerManager.append(backgroundSprite);

    }

    // Automatically start thread for game loop
    public void start()
    {
        isPlay = true;
        Thread t = new Thread(this);
        t.start();
    }

    public void stop()
    {
        isPlay = false;
    }

    // Main Game Loop
    public void run()
    {
        Graphics g = getGraphics();
        while (isPlay == true)
        {
            input();
            drawScreen(g);
            try
            {
                Thread.sleep(delay);
            }
            catch (InterruptedException ie)
            {

            }
        }
    }

    // Method to Handle User Inputs
    private void input()
    {
        int keyStates = getKeyStates();

        playerSprite.setFrame(0);
        if(isalive)
        {
            if(counter==0)
            {
                enemyDirect=Math.abs(random.nextInt()%4);
            }
            counter++;
            switch(enemyDirect)
            {
                case 0:
                    enemyY=Math.max(0,--enemyY);
                    break;
                case 1:
                    enemyY=Math.min(++enemyY,height-enemySprite.getHeight());
                    break;
                case 2:
                    enemyX=Math.max(0,--enemyX);
                    break;
                case 3:
                    enemyX=Math.min(++enemyX,width-enemySprite.getWidth());
                    break;
            }
            counter=(counter++)%(sequence.length());
            enemySprite.setFrame(sequence[counter]);
        }
        else
        {
            enemyY+=counter;
            enemyY=Math.min(enemyY,height-enemySprite.getHeight());

            if(enemyY<height-enemySprite.getHeight())
                counter++;
            enemySprite.setFrame(3);
        }

        // Left
        if ((keyStates & LEFT_PRESSED) != 0)
        {
            currentX = Math.max(0, currentX - 1);
            playerSprite.setFrame(1);
        }

        // Right
        if ((keyStates & RIGHT_PRESSED) != 0)
            if (currentX + 5 < width)
            {
                currentX = Math.min(width, currentX + 1);
                playerSprite.setFrame(3);
            }

        // Up
        if ((keyStates & UP_PRESSED) != 0)
        {
            currentY = Math.max(0, currentY - 1);
            playerSprite.setFrame(2);
        }

        // Down
        if ((keyStates & DOWN_PRESSED) != 0)
        {
            isdown=true;
        }

        if ((keyStates & DOWN_PRESSED) != 0)
        {
            if(isdown)
            {
                if (currentY + 10 < height)
                {
                    currentY = Math.min(height, currentY + 1);
                    playerSprite.setFrame(4);
                }
            }
        }

        if((keyStates & FIRE_PRESSED)!=0)
        {
            isalive=!isalive;
            counter=0;
        }

        if(!(enemyX+enemySprite.getWidth()<currentX 
		|| enemyY+enemySprite.getHeight()<currentY 
		|| enemyX>currentX+playerSprite.getWidth() 
		|| enemyY>currentY+playerSprite.getHeight()) && isalive)
        {
            counter=0;
            isalive=false;
        }
    }

    // Method to Display Graphics
    private void drawScreen(Graphics g)
    {
        g.setColor(0xffffff);
        g.fillRect(0, 0, getWidth(), getHeight());
        g.setColor(0x0000ff);

        // updating player sprite position
        playerSprite.setPosition(currentX, currentY);
        enemySprite.setPosition(enemyX,enemyY);

        layerManager.setViewWindow(0, 0, width, height);
        layerManager.paint(g, 0,0);

        g.setColor(0xffffff);
        flushGraphics();
    }

}

此程序里敌人随机向4个方向移动，而玩家控制的角色可任意移动，如果两者发生碰撞，则敌人死亡。另外按fire键可直接让敌人生或死，关于运行，Jbuilder里有个运行配置: