When using shallow view, images are not visible, but they are drawn to view in android

I am drawing some bitmaps to canvas in which my class is view-enhanced, then everything works fine, but I found it lacks efficiency. So I looked for other alternatives and found that we needed to extend the class to a surface to be more efficient. Therefore, I am currently drawing bitmaps using a surface view. But here is the problem when I change and run the program I cannot see bitmaps but onDraw () is called and user touches are handled by my view. I did some searches on this but couldn't find anything. Can you please let me know, although the images are being drawn on the preview, why the images are not displayed ???

thank