iOS 9：如何使滚动条底部的内容视图固定在scrollview底部？

Question

I have a UIScrollView whose backgroundColor is UIColor.clearColor(). That scroll view's content view has background color red and take advantage of the standard bouncing feature.

But when I scroll it upwards, when the scroll exceeds the contentSize height, the underlying views appears (reminding you the scroll background being clear color). See the image:

My code is quite standard:

    scrollView.delegate           = self
    scrollView.backgroundColor    = UIColor.clearColor()
    scrollView.contentSize        = view.frame.size

    view.addSubview(scrollView)

Answer 1

I'd keep it simple and just add another view behind the scroll view at the bottom of the screen, probably about half the height of the view, and the same colour as the background. So, when you scroll the content up you just see through to that view instead of the content behind.

You could turn bouncing on and off depending on the scroll direction but you'd get little UI glitches. You could add a delegate for the scroll gesture recogniser and use gestureRecognizer:shouldReceiveTouch: but you could end up with similar UI issues.

Answer 2

Add a UIView into your scrollView with the same color as your content background color. Set its frame so its outside the scrollView.contentSize (ie: y < 0 at the top, y > contentSize.height at the bottom). Make it big enough to cover the bounce gap.