How to hide a UIView while scrolling? - ios

Question

I am trying to achieve this effect.
I am trying to hide a view, as the user scrolls up, and reveal it as the user scrolls down.
I do not know how to go about this.
I have tried looking as the scrollView didScroll function, but I am lost as how to set this up. Any advice?

Answer 1

I solved like this:
private var lastContentOffset: CGFloat = 0
func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
lastContentOffset = scrollView.contentOffset.y
}
func scrollViewDidScroll(_ scrollView: UIScrollView) {
if lastContentOffset > scrollView.contentOffset.y {
UIView.animate(withDuration: 0.25, animations: { [weak self] in
self?.addDeviceButton.alpha = 1.0
self?.addDeviceButton.transform = CGAffineTransform(scaleX: 1.0, y: 1.0)
}, completion: nil)
} else if lastContentOffset < scrollView.contentOffset.y {
UIView.animate(withDuration: 0.25, animations: { [weak self] in
self?.addDeviceButton.alpha = 0
self?.addDeviceButton.transform = CGAffineTransform(scaleX: 1.3, y: 1.3)
}, completion: nil)
}
}

Answer 2

Hiding content on scroll
Please check this library it do exactly what your attached gif do.
The other way around would be from the gif file attached by you would be.
Add search bar on top. And make hiding part as a header and aligned the search bar and tableview to get that animation.

Answer 3

You need to set up the container view for the scroll view and the view you want to hide as the delegate for the scroll view, registering this class to conform to the UIScrollViewDelegate protocol.
You also need to keep track of the scroll view’s content offset property, and setvthis to the initial offset of the scroll view when it is created:
fileprivate var scrollOffset : CGPoint
Then, as you say, use the scrollViewDidScroll method:
internal func scrollViewDidScroll(_ scrollView: UIScrollView) {
let delta : CGPoint = CGPoint(x: scrollView.contentOffset.x - scrollOffset.x,
y: scrollView.contentOffset.y - scrollOffset.y)
if delta.y > 0, subviewToFade.isDescendant(of: self) {
// fade out subviews and remove
else if delta < 0, !subviewToFade.isDescendant(of: self) {
// add subviews and fade back in
}
scrollOffset = scrollView.contentOffset
}
Hope that helps.

Answer 4

here is my constraints
func scrollViewDidScroll(_ scrollView: UIScrollView) {
setPosition(scrollView)
}
func setPosition(_ scrollView:UIScrollView) {
if scrollView.contentOffset.y >= 20 {
self.parentTopViewcontraints.constant = -95 // set postition till you want to hide your view
UIView.animate(withDuration: 0.5) {
self.view.layoutIfNeeded()
}
}else if scrollView.contentOffset.y <= 200 {
self.parentTopViewcontraints.constant = 0 //set back
UIView.animate(withDuration: 0.5) {
self.view.layoutIfNeeded()
}
}
}