gamedemo.java

jBuilderX无线应用开发源代码

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

public class GameDemo extends MIDlet implements CommandListener{

	private LayerCanvas gameCanvas;
	private final static Command exit = new Command("Exit", Command.EXIT, 1);
  
	public void startApp() {
		if (gameCanvas== null) {
			gameCanvas= new LayerCanvas(); 
			gameCanvas.addCommand(exit);
			gameCanvas.setCommandListener(this);
		}  
		gameCanvas.startGame();     
		Display.getDisplay(this).setCurrent(gameCanvas);
	} 
	
	public void pauseApp() {
		if (gameCanvas != null){
			gameCanvas.stopGame();
		}
	}

	public void destroyApp(boolean unconditional) {
		if (gameCanvas != null){
			gameCanvas.stopGame();
		}
	}

	public void commandAction(Command c, Displayable s){
       if (c == exit) {
			destroyApp(false);
			notifyDestroyed();
		}
	}
}

//该类继承了GameCanvas类，并封装了游戏的运行逻辑
class LayerCanvas extends GameCanvas implements Runnable{
	//指示游戏是否结束
	boolean gameOver;	
	//绘制图像缓冲区的Graphics对象
	private Graphics g;

	//游戏中用到的Sprite对象
	private Sprite sprite;
	//Sprite的位置
	private int x,y;
	//Sprite的移动速度
	private int speed=5;

	//GameCanvas的宽度和高度
	private int width,height;	
	//游戏背景TiledLayer对象
	private TiledLayer background;  
	//管理各个Layer的LayerManager对象
	private LayerManager mng;	

	//Sprite中每帧图像的宽度和高度
	private static final int SPRIT_FRAME_WIDTH = 45;
	private static final int SPRIT_FRAME_HEIGHT = 18;

	public LayerCanvas (){
		super(true);
		//获得绘制图像缓冲区的Graphics对象
		g=getGraphics();
		//创建管理各个Layer的LayerManager对象
		mng=new LayerManager();
		
		//用图像文件mosquito.png创建Image对象
		Image img=null;
		try{		
			img=Image.createImage("/mosquito.png");	
		}
		catch(java.io.IOException e){
			System.out.println("can not open image file：mosquito.png");
		}
		//用Image对象创建sprite对象
		sprite=new Sprite(img,SPRIT_FRAME_WIDTH,SPRIT_FRAME_HEIGHT);
		//把创建的sprite对象添加到LayerManager中
		mng.append(sprite);

		//创建背景图像		
		createBackground();		

		//设置Sprite的初始位置
		x=0;
		y=20;

		//获得GameCanvas的宽度和高度
		width=getWidth();
		height=getHeight();	
	}

	public void createBackground(){
		try{
		    Image img=Image.createImage("/tile.png");
		    background=new TiledLayer(12,4,img,32,32);
		    background.createAnimatedTile(5);
		    int[] map = {
       			0,  0,  1,  3,  0,  0,  0,  0,  0,  0,  0,  0,
       			0,  1,  4,  4,  3,  0,  0,  0,  0,  1,  2,  2,
       			1,  4,  4,  4,  4,  3,  0,  0,  1,  4,  4,  4,
      		    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
    		};
		    for(int i=0;i<map.length;i++){
			int column=i%12;
			int row=(i-column)/12;
			background.setCell(column, row, map[i]);
		    }
		    mng.append(background);
		}
		catch(java.io.IOException e){
		    System.out.println("can not open image file：tile.png");
		}
	}

	//开始游戏运行
	public void startGame(){	
		gameOver=false;
		Thread t=new Thread(this);
		t.start();		
	}

	//停止游戏运行
	public void stopGame(){
		gameOver=true;
	}

	//游戏主循环
	public void run(){

		//用于显示背景上的水流动画
	    int i=5;
		
		//临时保存Sprite的位置，用于在发生碰撞冲突时恢复原来的位置
	    int tempx=x,tempy=y;	

	    while(!gameOver){
			//查询键盘状态
			int keyState=this.getKeyStates();	

			//如果方向键按下，则移动Sprite，并保证Sprite在游戏场景区域内
			if((keyState&RIGHT_PRESSED)!=0){
				tempx=x-speed;
				if(tempx<width-12*32)
					tempx=width-12*32;
			}
			if((keyState&LEFT_PRESSED)!=0){
				tempx=x+speed;
				if(tempx>0)
					tempx=0;
			}
			if((keyState&UP_PRESSED)!=0){
				tempy=y-speed;
				if(tempy<20)
					tempy=20;
			}
			if((keyState&DOWN_PRESSED)!=0){
				tempy=y+speed;
				if(tempy>height)
					tempy=height;
			}

			//设置背景和Sprite的新位置，以产生Sprite移动的效果
			background.setPosition(tempx,height-128);
			sprite.setPosition(40,tempy);

			//如果发生碰撞冲突，则恢复原来的位置
			if(sprite.collidesWith(background,false)){
				background.setPosition(x,height-128);
				sprite.setPosition(40,y);
			}
			//没有碰撞冲突，就把新位置保存下来
			else{
				x=tempx;
				y=tempy;
			}

			//清除背景
			g.setColor(128,255,255);
			g.fillRect(0,0,width,height);	

			//设置水流动画
			i=i+1;
			if(i>7)
				i=5;
			background.setAnimatedTile(-1,i);

			//Sprite后移一帧
			sprite.nextFrame();

			//设置显示区域
			mng.setViewWindow(0,20,width,height-20);

			//绘制游戏场景
			mng.paint(g,0,20);

			//绘制屏幕上方的游戏提示区域
			g.setColor(0,0,0);
			g.fillRect(0,0,width,20);
			g.setColor(255,255,0);
			g.fillRect(0,5,width,10);
			g.setColor(255,0,0);
			int pos=(40-x)*width/(12*32);
			g.fillArc(pos-5,5,10,10,0,360);

			//把绘制好的图像由缓冲区复制到实际屏幕
			flushGraphics();
			
			//延时
			try { 
				Thread.sleep(50); 
			}
			catch (InterruptedException ie) {
			}				
	    }
	}
}