android游戏开发学习笔之七 （学习书籍 Android游戏编程之从零开始）

/**

* 可视区域

*

* @time 上午10:42:39

* @author retacn yue

* @Email zhenhuayue@sina.com

*/

@SuppressWarnings("unused")

public class ClipCanvasSurfaceView extends SurfaceView implements Callback, Runnable {

private boolean flag;// surfaceView状态标志位

private SurfaceHolder sfh;

private Paint paint;

private Bitmap bitmap;

private Thread thread;

private Canvas canvas;

private int screenX, screenY;

public ClipCanvasSurfaceView(Context context) {

super(context);

/********** 画图所必需 *********************/

sfh = this.getHolder();// 获得surfaceHolder对象

sfh.addCallback(this);

thread = new Thread(this);

paint = new Paint();// 新建画笔

paint.setColor(Color.WHITE);// 设置画笔颜色

paint.setAntiAlias(true);// 消除锯齿

this.setKeepScreenOn(true);// 保持屏幕常亮

this.setFocusable(true);

/********************************************/

bitmap = BitmapFactory.decodeResource(this.getResources(), R.drawable.icon);

}

@SuppressWarnings("static-access")

@Override

public void run() {

while (flag) {

// 绘图

draw();

try {

thread.sleep(100);

} catch (InterruptedException e) {

e.printStackTrace();

}

}

}

/**

* 绘图

*/

private void draw() {

try {

canvas = sfh.lockCanvas();

if (null != canvas) {

// 填充，充当刷屏

canvas.drawColor(Color.BLACK);

// 矩形可见区域

/*

* canvas.save(); canvas.clipRect(0, 0, 20, 20);//矩形大小

* canvas.drawBitmap(bitmap, 0, 0, paint); canvas.restore();

*/

// 利用path设置可见区域

/*

* canvas.save(); Path path=new Path(); path.addCircle(30, 30,

* 30, Direction.CCW); canvas.clipPath(path);

* canvas.drawBitmap(bitmap, 10, 10, paint);

*/

// 利用region设置可视区域

canvas.save();

Region region = new Region();

region.op(new Rect(20, 20, 100, 100), Region.Op.UNION);

region.op(new Rect(40, 20, 80, 150), Region.Op.XOR);

canvas.clipRegion(region);

canvas.drawBitmap(bitmap, 0, 0, paint);

canvas.restore();

}

} catch (Exception e) {

e.printStackTrace();

} finally {

if (null != canvas) {

sfh.unlockCanvasAndPost(canvas);

}

}

}

/**

* 游戏逻辑

*/

private void logic() {

}

/**

* 创建surfaceView时使用

*/

@Override

public void surfaceCreated(SurfaceHolder holder) {

screenX = this.getWidth();

screenY = this.getHeight();

flag = true;

// 实例化线程

thread = new Thread(this);

thread.start();

}

/**

* 改变时调用

*/

@Override

public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

}

/**

* 销毁时调用

*/

@Override

public void surfaceDestroyed(SurfaceHolder holder) {

flag = false;

}

}