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 vo