J2ME RPG游戏边学边做（二）
文章来源：J2ME开发网
在写第二篇之前首先感谢favoyang在前一篇给我提出的几点建议。
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);
}
在io包中的读取是非常耗内存的，所以Image.createImage("/hero_down.png")放在线程的循环中确实不好，
现在已经改成图象在BraveCanvas类中创建(下面的代码已更改)，然后由moveDown(Image image)方法接收传递
进来的图象。
２、RPG是个大工程，一个人的力量是很难完成的，我只想实现基本的RPG功能，比如人物的对话，场景的
转换，战斗等等，希望大家多多给予帮助。
这一篇我将给游戏加入地图，以下是该篇所需要的图片：
background.png
foreground.png
一个RPG中的游戏地图是非常大而且多的，为了方便以后的维护，我创建了一个Scene类，该类主要是产
生游戏所需要的地图。
Scene.java
package brave;
import javax.microedition.lcdui.game.TiledLayer;
import javax.microedition.lcdui.Image;
public class Scene
{
public static TiledLayer createTiledLayerByBackground(Image image)
{
//使用TiledLayer创建地图
TiledLayer tiledLayer = new TiledLayer(10, 8, image, 48, 64);
tiledLayer.fillCells(0, 0, 10, 8, 2);
return tiledLayer;
}
}
修改BraveCanvas类，加入地图
BraveCanvas.java
package brave;
import javax.microedition.lcdui.game.GameCanvas;
import javax.microedition.lcdui.Graphics;
import java.io.IOException;
import javax.microedition.lcdui.Image;
import javax.microedition.lcdui.game.TiledLayer;
public class BraveCanvas extends GameCanvas implements Runnable
{
private boolean sign;
private Graphics g;
private Hero hero;
private Image upimage;
private Image downimage;
private Image leftimage;
private Image rightimage;
private TiledLayer backgroundMap;
public BraveCanvas()
{
super(true);
}
public void startup()
{
this.sign = true;
try
{
//产生地图
backgroundMap = Scene.createTiledLayerByBackground(
Image.createImage("/background.png"));
//改正上一篇的错误
upimage = Image.createImage("/hero_up.png");
downimage = Image.createImage("/hero_down.png");
leftimage = Image.createImage("/hero_left.png");
rightimage = Image.createImage("/hero_right.png");
hero = new Hero(upimage, 17, 26);
hero.setFrameSequence(new int[]{1, 1, 0, 0, 1, 1, 2, 2});
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)
{
e.printStackTrace();
}
}
}
public void input(Graphics g) throws IOException
{
int keystates = getKeyStates();
switch(keystates)
{
case UP_PRESSED:
//由这里传入需要改变的图片
hero.moveUp(upimage);
break;
case DOWN_PRESSED:
hero.moveDown(downimage);
break;
case LEFT_PRESSED:
hero.moveLeft(leftimage);
break;
case RIGHT_PRESSED:
hero.moveRight(rightimage);
break;
}
hero.afresh();
}
public void paint(Graphics g)
{
g.setColor(0x000000);
g.fillRect(0, 0, getWidth(), getHeight());
g.setColor(0xffffff);
//显示地图
backgroundMap.paint(g);
hero.paint(g);
flushGraphics();
}
}
现在我们的英雄虽然能在草地上行走了，但感觉给他移动的空间太小了。而且我们在创建背景地图的时
候，地图大小明明是512*480的。好，接下来我们要做的就是让英雄可以在更大的天地中活动。这里就需要一
个BraveManager类来管理这些屏幕上的Sprite和TiledLayer，该类继承LayerManager。
BraveManager.java
package brave;
import javax.microedition.lcdui.game.LayerManager;
public class BraveManager extends LayerManager
{
private BraveCanvas braveCanvas;
public void setBraveCanvas(BraveCanvas braveCanvas)
{
this.braveCanvas = braveCanvas;
}
public void afresh()
{
//确定当前试图的坐标
//这里用一个比较简单的算法来使英雄永远在屏幕的中央
int viewX = Math.max(0, getLayerAt(0).getX() - braveCanvas.getWidth()/2);
int viewY = Math.max(0, getLayerAt(0).getY() - braveCanvas.getHeight()/2);
viewX = Math.min(viewX, getLayerAt(1).getWidth() - braveCanvas.getWidth());
viewY = Math.min(viewY, getLayerAt(1).getHeight() - braveCanvas.getHeight());
setViewWindow(viewX, viewY, braveCanvas.getWidth(), braveCanvas.getHeight());
}
}
修改BraveCanvas类
BraveCanvas.java
package brave;
import javax.microedition.lcdui.game.GameCanvas;
import javax.microedition.lcdui.Graphics;
import java.io.IOException;
import javax.microedition.lcdui.Image;
import javax.microedition.lcdui.game.TiledLayer;
public class BraveCanvas extends GameCanvas implements Runnable
{
private boolean sign;
private Graphics g;
private Hero hero;
private Image upimage;
private Image downimage;
private Image leftimage;
private Image rightimage;
private TiledLayer backgroundMap;
//创建Layer管理视图类
private BraveManager braveManager;
public BraveCanvas()
{
super(true);
}
public void startup()
{
this.sign = true;
try
{
backgroundMap = Scene.createTiledLayerByBackground(
Image.createImage("/background.png"));
upimage = Image.createImage("/hero_up.png");
downimage = Image.createImage("/hero_down.png");
leftimage = Image.createImage("/hero_left.png");
rightimage = Image.createImage("/hero_right.png");
//创建Layer管理视图类
braveManager = new BraveManager();
braveManager.setBraveCanvas(this);
hero = new Hero(upimage, 17, 26);
hero.setFrameSequence(new int[]{1, 1, 0, 0, 1, 1, 2, 2});
hero.setBraveCanvas(this);
hero.setBraveManager(braveManager);
hero.init(0,0);
}
catch(Exception e)
{
e.printStackTrace();
}
Thread thread = new Thread(this);
thread.start();
}
public void run()
{
g = getGraphics();
//插入图层
braveManager.insert(hero, 0);
braveManager.insert(backgroundMap, 1);
while(sign)
{
try
{
input(g);
paint(g);
Thread.sleep(15);
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
public void input(Graphics g) throws IOException
{
int keystates = getKeyStates();
switch(keystates)
{
case UP_PRESSED:
hero.moveUp(upimage);
break;
case DOWN_PRESSED:
hero.moveDown(downimage);
break;
case LEFT_PRESSED:
hero.moveLeft(leftimage);
break;
case RIGHT_PRESSED:
hero.moveRight(rightimage);
break;
}
hero.afresh();
//刷新视图的位置
braveManager.afresh();
}
public void paint(Graphics g)
{
g.setColor(0x000000);
g.fillRect(0, 0, getWidth(), getHeight());
g.setColor(0xffffff);
//显示视图
braveManager.paint(g, 0, 0);
flushGraphics();
}
}
这样英雄就可以在地图上任何地方行动了，不过还得改一个小地方：
不知道大家还记的不，在Hero类中，我们定义英雄移动的范围最大为屏幕的尺寸。
这显然是不行的，最大的移动范围应改成地图的大小：
this.y = Math.min(braveManager.getLayerAt(1).getHeight(), y + 1);
this.x = Math.min(braveManager.getLayerAt(1).getWidth(), x + 1);
代码如下:
Hero.java
package brave;
import javax.microedition.lcdui.game.Sprite;
import javax.microedition.lcdui.Image;
import java.io.IOException;
import javax.microedition.lcdui.Graphics;
public class Hero extends Sprite
{
private int x;
private int y;
private BraveCanvas braveCanvas;
private BraveManager braveManager;
public Hero(Image image, int frameWidth, int frameHeight)
{
super(image, frameWidth, frameHeight);
}
public void setBraveCanvas(BraveCanvas braveCanvas)
{
this.braveCanvas = braveCanvas;
}
public void setBraveManager(BraveManager braveManager)
{
this.braveManager = braveManager;
}
public void setManager(BraveCanvas braveCanvas)
{
this.braveCanvas = braveCanvas;
}
public void init(int x, int y)
{
this.x = x;
this.y = y;
}
public void afresh()
{
setPosition(this.x, this.y);
}
public void moveUp(Image image) throws IOException
{
setImage(image, 17, 26);
nextFrame();
this.y = Math.max(0, y - 1);
}
public void moveDown(Image image) throws IOException
{
setImage(image, 17, 26);
nextFrame();
this.y = Math.min(braveManager.getLayerAt(1).getHeight(), y + 1);
}
public void moveLeft(Image image) throws IOException
{
setImage(image, 17, 26);
nextFrame();
this.x = Math.max(0, x - 1);
}
public void moveRight(Image image) throws IOException
{
setImage(image, 17, 26);
nextFrame();
this.x = Math.min(braveManager.getLayerAt(1).getWidth(), x + 1);
}
}
现在英雄的移动范围大了，但只英雄一人，也太孤单了，我们给他创造一个小镇吧。
修改Scene类如下：
Scene.java
package brave;
import javax.microedition.lcdui.game.TiledLayer;
import javax.microedition.lcdui.Image;
public class Scene
{
public static TiledLayer createTiledLayerByBackground(Image image)
{
TiledLayer tiledLayer = new TiledLayer(10, 8, image, 48, 64);
tiledLayer.fillCells(0, 0, 10, 8, 2);
return tiledLayer;
}
public static TiledLayer createTiledLayerByForeground(Image image)
{
TiledLayer tiledLayer = new TiledLayer(30, 32, image, 16, 16);
// 30 * 32
int[] maplist =
{
//0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
26 27 28 29
0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0
,0 ,0 ,0 ,0 ,0 ,//0
0
,28,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,30,0 ,//1
0 ,34,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0
,0 ,0 ,0 ,36,0 ,//2
0 ,34,0 ,1 ,2 ,3 ,4 ,5 ,0 ,0 ,0 ,1 ,2 ,3 ,3 ,26,3 ,3 ,4 ,5 ,0 ,0 ,1 ,2 ,3
,4 ,5 ,0 ,36,0 ,//3
0 ,34,0 ,7 ,8 ,46,10,11,0 ,0 ,0 ,7 ,8 ,47,31,32,33,47,10,11,0 ,0 ,7 ,8
,46,10,11,0 ,36,0 ,//4
0 ,34,0 ,13,14,15,16,17,0 ,0 ,0 ,13,14,14,37,38,39,14,16,17,0 ,0
,13,14,15,16,17,0 ,36,0 ,//5
0 ,34,0 ,19,20,21,22,23,6 ,0 ,0 ,19,20,20,43,44,45,20,20,23,0 ,0
,19,20,21,22,23,0 ,36,0 ,//6
0 ,34,0 ,0 ,0 ,12,0 ,0 ,0 ,0 ,0 ,24,24,24,13,15,17,24,24,24,0 ,0 ,0 ,0
,12,0 ,0 ,0 ,36,0 ,//7
0 ,34,0 ,0 ,0 ,12,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,19,21,23,0 ,0 ,0 ,0 ,0 ,0 ,0
,12,0 ,0 ,0 ,36,0 ,//8
0 ,34,0 ,0 ,0 ,12,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,12,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0
,12,0 ,0 ,0 ,36,0 ,//9
0 ,34,0 ,0 ,0
,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,0 ,0 ,0 ,36,0 ,//10
0 ,34,0 ,0 ,0 ,0 ,0 ,0 ,0 ,12,25,25,25,25,25,25,25,25,25,25,12,0 ,0 ,0 ,0
,0 ,0 ,0 ,36,0 ,//11
0 ,34,0 ,1 ,2 ,3 ,4 ,5 ,0 ,12,25,25,25,25,25,25,25,25,25,25,12,0 ,1 ,2 ,3
,4 ,5 ,0 ,36,0 ,//12
0 ,34,0 ,7 ,8 ,46,10,11,0 ,12,25,25,25,25,25,25,25,25,25,25,12,0 ,7 ,8
,46,10,11,0 ,36,0 ,//13
0 ,34,0 ,13,14,15,16,17,0 ,12,25,25,25,25,25,25,25,25,25,25,12,0
,13,14,15,16,17,0 ,36,0 ,//14
0 ,34,0 ,19,20,21,22,23,0 ,12,25,25,25,25,25,25,25,25,25,25,12,0
,19,20,21,22,23,0 ,36,0 ,//15
0 ,34,0 ,0 ,0 ,12,0 ,0 ,0 ,12,25,25,25,25,25,25,25,25,25,25,12,0 ,0 ,0
,12,0 ,0 ,0 ,36,0 ,//16
0 ,34,0 ,0 ,0 ,12,0 ,0 ,0 ,12,25,25,25,25,25,25,25,25,25,25,12,0 ,0 ,0
,12,0 ,0 ,0 ,36,0 ,//17
0 ,34,0 ,0 ,0 ,12,0 ,0 ,0 ,12,25,25,25,25,25,25,25,25,25,25,12,0 ,0 ,0
,12,0 ,0 ,0 ,36,0 ,//18
0 ,34,0 ,0 ,0
,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,0 ,0 ,0 ,36,0 ,//19
0 ,34,0 ,0 ,0 ,0 ,0 ,0 ,0 ,12,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,12,0 ,0 ,0 ,0
,0 ,0 ,0 ,36,0 ,//20
0 ,34,0 ,0 ,0 ,0 ,0 ,0 ,0 ,12,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,12,0 ,0 ,0 ,0
,0 ,0 ,0 ,36,0 ,//21
0 ,34,0 ,1 ,2 ,3 ,4 ,5 ,0 ,12,0 ,0 ,0 ,0 ,1 ,3 ,5 ,0 ,0 ,0 ,12,0 ,1 ,2 ,3
,4 ,5 ,0 ,36,0 ,//22
0 ,34,0 ,7 ,8 ,46,10,11,0 ,12,0 ,0 ,0 ,0 ,7 ,48,11,0 ,0 ,0 ,12,0 ,7 ,8
,46,10,11,0 ,36,0 ,//23
0 ,34,0 ,13,14,15,16,17,0 ,12,0 ,0 ,0 ,6 ,13,15,17,0 ,0 ,0 ,12,0
,13,14,15,16,17,0 ,36,0 ,//24
0 ,34,0 ,19,20,21,22,23,0 ,12,0 ,0 ,0 ,6 ,19,21,23,0 ,0 ,0 ,12,0
,19,20,21,22,23,0 ,36,0 ,//25
0 ,34,0 ,0 ,0 ,12,0 ,0 ,0 ,12,18,0 ,0 ,0 ,0 ,12,0 ,0 ,0 ,0 ,12,0 ,0 ,0
,12,0 ,0 ,0 ,36,0 ,//26
0 ,34,0 ,0 ,0
,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,0 ,0 ,0 ,36,0 ,//27
0 ,34,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,12,12,12,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0
,0 ,0 ,0 ,36,0 ,//28
0 ,34,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,12,12,12,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0
,0 ,0 ,0 ,36,0 ,//29
0
,40,29,29,29,29,29,29,29,29,29,29,29,29,12,12,12,29,29,29,29,29,29,29,29,29,29,29,42,0 ,//30
0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0
,0 ,0 ,0 ,0 ,0 //31
};
for(int i = 0 ; i < maplist.length ; i++)
{
int col = i % 30;
int row = (i - col) / 30;
tiledLayer.setCell(col, row, maplist[i]);
}
return tiledLayer;
}
}
修改BraveCanvas类如下：
BraveCanvas.java
package brave;
import javax.microedition.lcdui.game.GameCanvas;
import javax.microedition.lcdui.Graphics;
import java.io.IOException;
import javax.microedition.lcdui.Image;
import javax.microedition.lcdui.game.TiledLayer;
public class BraveCanvas extends GameCanvas implements Runnable
{
private boolean sign;
private Graphics g;
private Hero hero;
private Image upimage;
private Image downimage;
private Image leftimage;
private Image rightimage;
private TiledLayer backgroundMap;
private TiledLayer foregroundMap;
private BraveManager braveManager;
public BraveCanvas()
{
super(true);
}
public void startup()
{
this.sign = true;
try
{
backgroundMap = Scene.createTiledLayerByBackground(
Image.createImage("/background.png"));
//生成小镇地图
foregroundMap = Scene.createTiledLayerByForeground(
Image.createImage("/foreground.png"));
upimage = Image.createImage("/hero_up.png");
downimage = Image.createImage("/hero_down.png");
leftimage = Image.createImage("/hero_left.png");
rightimage = Image.createImage("/hero_right.png");
braveManager = new BraveManager();
braveManager.setBraveCanvas(this);
hero = new Hero(upimage, 17, 26);
hero.setFrameSequence(new int[]{1, 1, 0, 0, 1, 1, 2, 2});
hero.setBraveCanvas(this);
hero.setBraveManager(braveManager);
hero.init(0,0);
}
catch(Exception e)
{
e.printStackTrace();
}
Thread thread = new Thread(this);
thread.start();
}
public void run()
{
g = getGraphics();
braveManager.insert(hero, 0);
//插入小镇地图
braveManager.insert(foregroundMap, 1);
braveManager.insert(backgroundMap, 2);
while(sign)
{
try
{
input(g);
paint(g);
Thread.sleep(15);
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
public void input(Graphics g) throws IOException
{
int keystates = getKeyStates();
switch(keystates)
{
case UP_PRESSED:
hero.moveUp(upimage);
break;
case DOWN_PRESSED:
hero.moveDown(downimage);
break;
case LEFT_PRESSED:
hero.moveLeft(leftimage);
break;
case RIGHT_PRESSED:
hero.moveRight(rightimage);
break;
}
hero.afresh();
braveManager.afresh();
}
public void paint(Graphics g)
{
g.setColor(0x000000);
g.fillRect(0, 0, getWidth(), getHeight());
g.setColor(0xffffff);
braveManager.paint(g, 0, 0);
flushGraphics();
}
}
运行结果如图：
这一篇就写到这了。
现在终于有点RPG游戏的样子了，不过我们的英雄似乎可以穿墙走壁啊。在下一篇中我将加入碰撞检测和人
物对话。
写到这已经创建五个类了（j2ee写习惯了：）），不知道是不是多了，大家多提点意见。而且也有很多地方设
计的不是很合理，以后的开发也许会出现点问题，好在我只是单纯的实现功能。
在确定英雄始终在地图中央的那段程序，总感觉有点烦琐，不知道大家是怎么写的，希望各位高手指导指导。
