android - Canvas未在SurfaceView中绘制到Bitmap

Question

我正在尝试用android做游戏。为了渲染我使用SurfaceView类。这是我的渲染方法：

        canvas = sHolder.lockCanvas(null);
        if(canvas==null)continue;
        canvas.drawColor(0xFF000000);
        w=canvas.getWidth();
        h=canvas.getHeight();
        //Commented code below is working
        /*Path pt = new Path();
        pt.moveTo(50,300);
        pt.lineTo(400,300);
        pt.cubicTo(450,200,500,400,600,600);
        canvas.drawPath(pt,p);
        canvas.drawTextOnPath("T E S T I N G . . .",pt,50,10,p);*/
        //canvas.drawBitmap(texPly, null, new Rect(50,114,114,114), null);
        canvas.drawBitmap(texBox, null, new Rect(50,114,114,114), null);

初始化texBox变量的代码：

    int[] buf = new int[16*16];
    Random r = new Random();
    for(int i=0;i<buf.length;i++)buf[i]=r.nextInt();
    texBox = Bitmap.createBitmap(buf,16,16,Bitmap.Config.RGB_565);

如果这可以帮助某种方式 - Android版本是KitKat 那么这段代码有什么问题呢？