Scroll a background in a different speed on a UIScrollView

Question

When somebody does a wipe gesture to scroll the content from left to right, I would like to have a background image scrolling into the same direction, but at a different spe

Answer 1

You can easily do this by implementing scroll view did scroll with a UIImageView under it... You'll end up with something like this... with the backgroundImageView being a UIImageView added to the view before the subview... you can layer as much image views as you want without performance issues

    - (void)scrollViewDidScroll:(UIScrollView *)scrollView
    {    
         float factor = scrollView.contentOffset.x / (scrollView.contentSize.width - 320);
         if (factor < 0) factor = 0;
         if (factor > 1) factor = 1;

         CGRect frame = backgroundImageView.frame;
         frame.origin.x = factor * (320 - backgroundImageView.frame.size.width);
         backgroundImageView.frame = frame;
    }