How can we change the background color of tableview (style grouped) while still preserving texture of thin columns/lines effect that we can see when it has the default blue
Firstly, you could try searching on Stack overflow for your exact question. Here's two:
If that doesn't help, try to make the background colour of the table view transparent [UIColor clearColor]
and put another view behind your UITableview containing the colout/texture/image you need.