安卓游戏开发_基础环境获取代码

public class PinBall extends Activity{
    
    private int tableHeight;
    private int tableWidth;
    Random random = new Random();
    
    //挡板大小和坐标
    private final int racket_width = 70;
    private final int racket_height = 20;
    private int racketY;
    private int racketX;
    
    //球体大小,速度,坐标
    private final int ballR = 12;
    private int ballX;
    private int ballY;
    private int Vy = 3;
    //生成一个比率(-0.5~0.5之间),用于产生随机方向
    private double xyRate = random.nextDouble() - 0.5;
    private int Vx = (int) (Vy * 2 * xyRate); 
    
    //游戏进行时标志
    private boolean isLose = false;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        //全屏无标题
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, 
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
        //设置游戏界面
        final GameView game = new  GameView(this);
        setContentView(game);
        //获取桌面大小
        WindowManager manager = getWindowManager();
        Display display = manager.getDefaultDisplay();
        tableHeight = display.getHeight();
        tableWidth = display.getWidth();
        //根据获取的桌面大小初始化坐标
        initXY();
        
        //重绘
        final Handler handler = new Handler(){
            public void handleMessage(Message message){
                if(message.what == 0x123){
                    game.invalidate();
                }
            }
        };
        
        final Timer timer = new Timer();
        timer.schedule(new TimerTask() {
            
            @Override
            public void run() {
                //左右边框
                if(ballX < 0 || (ballX + ballR > tableWidth)){
                    Vx = -Vx;
                }
                //超过下边界且未被球拍接住
                if((ballY + ballR > racketY) && (ballX + ballR < racketX || ballX > racketX + racket_width)){
                    timer.cancel();
                    isLose = true;
                }
                //被球拍打回或者反弹时到达顶部
                if(ballY < 0 || (ballY + ballR > racketY && ballX > racketX && ballX < racketX + racket_width )){
                    Vy = -Vy;
                }
                ballX += Vx;
                ballY += Vy;
                handler.sendEmptyMessage(0x123);
            }
        }, 0, 10);
        
        //给游戏view加监听器
        game.setOnTouchListener(new OnTouchListener() {
            
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                int x = (int) event.getX();
                int mid = tableWidth/2;
                switch (x > mid ? 1 : 2) {
                case 1:
                    if(racketX + racket_width < tableWidth){
                        racketX += 10;    
                    }
                    break;
                case 2:
                    if(racketX > 0){
                        racketX -= 10;
                    }
                    break;
                }
                game.invalidate();
                return true;
            }
        });
        
    }
    
    private void initXY(){
        racketY = tableHeight - 80;
        racketX = random.nextInt(tableWidth);
        ballX = random.nextInt(tableWidth);
        ballY = random.nextInt(10) + 20;
    }
    
    class GameView extends View{

        private static final float TEXT_SIZE = 40;

        public GameView(Context context) {
            super(context);
            // TODO Auto-generated constructor stub
            setFocusable(true);
        }

        @Override
        protected void onDraw(Canvas canvas) {
            Paint paint = new Paint();
            paint.setStyle(Paint.Style.FILL);
            //游戏结束
            if (isLose) {
                paint.setTextSize(TEXT_SIZE);
                paint.setColor(Color.RED);
                canvas.drawText("Game Over!", tableWidth/2 - paint.getTextSize()*2, tableHeight/2 - paint.getTextSize()/2, paint);
            }
            //游戏继续
            else {
                paint.setColor(Color.BLUE);
                canvas.drawCircle(ballX, ballY, ballR, paint);
                paint.setColor(Color.GREEN);
                canvas.drawRect(racketX, racketY, racketX + racket_width, racketY + racket_height, paint);
                
            }
        }
        
        
    }
}