//collideDemo.java file
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.game.*;
import java.util.*;

public class collideDemo extends MIDlet implements CommandListener
{
    private Command exitCommand,actCommand;
    private DemoCanvas canvas;
    private DemoTask task ;
    private Timer timer;
    public collideDemo()
    {//創建命令，畫布和定時器
        exitCommand =new Command("Exit",Command.EXIT,1);
        actCommand =new Command("Action",Command.SCREEN,1);
        canvas =new DemoCanvas();
        canvas.addCommand(actCommand);
        canvas.addCommand(exitCommand);
        canvas.setCommandListener(this);
        timer = new Timer();
        task = new DemoTask(canvas);
    }
    protected void startApp(  ) 
    {//顯示畫布并開始游戲執行
        Display.getDisplay(this).setCurrent(canvas);
        timer.schedule(task, 0,100);
    }

    protected void pauseApp(  )
    {
        timer.cancel();
    }

    protected void destroyApp( boolean p1 )
    {
    }

    public void commandAction(Command c,Displayable d)
    {
        if (c ==exitCommand)
        {
            destroyApp(false);
            notifyDestroyed();
        }
        else if (c ==actCommand)
            canvas.Action();
    }
    public class DemoCanvas extends GameCanvas
    {
        private Graphics g;
        private TiledLayer backLayer0;//背景圖層
        private Image backImage0,objImage0,objImage1;//保存圖像
        private Sprite objSprite0,objSprite1;//精靈
        private int aniCounter =0;//計數器
        private final int left2rightSeq[]={0, 1, 2, 3};//小球0的動畫序列
        private final int right2leftSeq[]={3, 2, 1, 0};//小球1的動畫序列
        private LayerManager layerMan;//圖層管理對象
        private int moveMode =0;//移動模式，0：移動小球0，1：移動小球1
        private int xDirection=0, yDirection=0;//移動距離
        //記錄圖層backLayer0的每個單元對應的圖像塊序號
        private byte[ ][ ] backMap= 
            {{1, 2, 2, 2, 2, 2, 2, 4},
             {6, 0, 0, 0, 0, 0,12, 7},
             {6, 0, 0, 0,10, 0, 0, 7},
             {6, 0, 0, 0, 0, 0, 0, 7},
             {6, 0, 0, 0, 0, 0,11, 7},
             {6, 0, 0, 0, 9, 0, 0, 7},
             {6, 0,11, 0, 0, 0, 0, 7},
             {5, 3, 3, 3, 3, 3, 3, 8}};
        public DemoCanvas() 
        {
            super(true);
            g = getGraphics();//得到作圖對象
            try 
            {//裝入圖像
                backImage0 = Image.createImage("/collide_bk.png");
                objImage0 = Image.createImage("/collide1.png");
                objImage1 = Image.createImage("/collide2.png");
            } catch (Exception e) {}
            //創建圖層，分塊大小為：17×17，單元格數量為：6×6
            backLayer0 = new TiledLayer(8, 8, backImage0, 17, 17);
            for(int y=0;y<8;y++)
            {//逐個設置每個單元格的圖像，標記為0的單元格表示不處理
                for(int x=0;x<8;x++)
                    backLayer0.setCell(x, y, backMap[y][x]);
            }
            objSprite0 = new Sprite(objImage0, 17,17);
            objSprite0.setFrameSequence(left2rightSeq);
            objSprite0.defineCollisionRectangle(0, 0, 17, 17);
            objSprite0.move(20,20);
            
            objSprite1 = new Sprite(objImage1, 17,17);
            objSprite1.setFrameSequence(right2leftSeq);
            objSprite1.defineCollisionRectangle(0, 0, 17, 17);
            objSprite1.move(40,40);

            layerMan = new LayerManager();
            layerMan.append(objSprite0);
            layerMan.append(objSprite1);
            layerMan.append(backLayer0);
        }

        public void BallAction0()
        {//直接修改單元格內的圖像
            objSprite0.nextFrame();//動畫效果
            objSprite0.move(xDirection, yDirection);//移動
            //檢測碰撞，不采用象素級檢查
            if( objSprite0.collidesWith(backLayer0,false)
                || objSprite0.collidesWith(objSprite1,false) )
            {//如果移動后和其他背景或另一個物體發生碰撞則返回到原來位置
                objSprite0.move(-xDirection, -yDirection);
            }
        }
        public void BallAction1()
        {//對第一球進行滾動
            objSprite1.nextFrame();//動畫效果
            objSprite1.move(xDirection, yDirection);//移動
            //檢測碰撞，采用象素級檢查
            if( objSprite1.collidesWith(backLayer0,true) 
                || objSprite1.collidesWith(objSprite0,true) )
            {//如果移動后和其他背景或另一個物體發生碰撞則返回到原來位置
                objSprite1.move(-xDirection, -yDirection);
            }
        }
        public void CheckKey()
        {
            int keyState = getKeyStates();
            //判斷AB鍵是否被按下，用于在不同的小球間切換
            if((keyState & GAME_A_PRESSED) !=0)
                moveMode = 0;
            else if((keyState & GAME_B_PRESSED) !=0)
                moveMode = 1;
            //判斷上下左右鍵是否被按下，修改移動距離
            if((keyState & UP_PRESSED) !=0)
            {
                yDirection=-2;
            }
            else if((keyState & DOWN_PRESSED) !=0)
            {
                yDirection=2;
            }
            if((keyState & LEFT_PRESSED) !=0)
            {
                xDirection=-2;
            }
            else if((keyState & RIGHT_PRESSED) !=0)
            {
                xDirection=2;
            }
        }
        //執行游戲功能        
        public void Action()
        {
            aniCounter ++;//增加計時器
            g.setColor(0X00FFFFFF);
            g.fillRect(0,0, 136, 136);
            CheckKey();
            if( moveMode ==0)
                BallAction0();
            else
                BallAction1();
            xDirection = yDirection =0;
            layerMan.paint(g,0,0);
            //刷新屏幕
            flushGraphics();
        }
    }
    public class DemoTask extends TimerTask
    {
        private DemoCanvas canvas;
        public DemoTask(DemoCanvas can)
        {
            canvas = can;
        }
        public void run()
        {
            canvas.Action();
        }
    }
}