android – 画布中的帧速率绘制位图更好？

void drawFrame() {
        final SurfaceHolder holder = getSurfaceHolder();
    final BufferedInputStream buf;
    final Bitmap bitmap,rbitmap;

        Canvas c = null;
        try {
            c = holder.lockCanvas();
            if (c != null) {
        try {
        buf = new 
            BufferedInputStream(assets.
                    open(folder+"/"
                         +imageList[ilen++])
                    );
        bitmap = BitmapFactory.
            decodeStream(buf);
        rbitmap = Bitmap.createBitmap
            (bitmap,imageWidth,imageHeight,transmatrix,falsE);
        c.drawBitmap(rbitmap,paddingX,paddingY,null);
        if ( ilen >= imageCount ) ilen=0;
        }
        catch (Exception E) { e.printStackTrace(); }
            }
        } finally {
            if (c != null) holder.unlockCanvasAndPost(c);
        }

        // Reschedule the next redraw
        mHandler.removeCallBACks(mDrawCubE);
        if (mVisiblE) {
            mHandler.postDelayed(mDrawCube,fps);
        }
    }

其中“transmatrix”是之前预定义的缩放和旋转矩阵.

它应该以30fps渲染,但当然不会那样做.我最初的猜测是BufferedInputStream是一个因素.我应该缓存其中的一些,因为我和Bitmaps一起使用.但任何其他想法？我是否必须使用OpenGL黑客进行动态壁纸？