I have a UIScrollView which i want to scroll vertically. I am creating UIScrollView programmatically and facing problems with Auto layouts.
I have added single child into a UIScrollView and rest of the controls have been added on that child view.
Following Code will create UIScrollView and contentView of Scroll View
lazy var scrollView : UIScrollView = {
let scrollView = UIScrollView()
scrollView.translatesAutoresizingMaskIntoConstraints = false
scrollView.keyboardDismissMode = .onDrag
// scrollView.backgroundColor = .red
return scrollView
}()
let contentView: UIView = {
let contentV = UIView()
contentV.translatesAutoresizingMaskIntoConstraints = false
contentV.backgroundColor = UIColor.yellow
return contentV
}()
Following Code will add UIScrollView inside main view and contentView inside UIScrollView
view.addSubview(scrollView)
scrollView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor).isActive = true
scrollView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor).isActive = true
scrollView.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor, constant: 8).isActive = true
scrollView.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor, constant: -8).isActive = true
//Content View
scrollView.addSubview(contentView)
contentView.widthAnchor.constraint(equalTo: view.widthAnchor).isActive = true
contentView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor).isActive = true
contentView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor).isActive = true
contentView.topAnchor.constraint(equalTo: scrollView.topAnchor).isActive = true
contentView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor).isActive = true
after doing this I am trying to add other controls on the contentView But my view is not showing properly, See the following image I have googled many tutorials for adding scroll view programmatically but unable to do it so.
Related
I'm trying to animate the hiding of the arranged subviews of a UIStackView:
UIView.animate(withDuration: 3, delay: 0) {
self.stackView.subviews.forEach({ $0.isHidden = true })
self.stackView.updateConstraintsIfNeeded()
self.stackView.layoutIfNeeded()
self.view.layoutIfNeeded()
} completion: { (_) in
self.children.forEach({ $0.removeFromParent() })
completion()
}
The problem is the views while animating expand in their width across the screen (out of screen bounds).
This is how the views are setup:
scrollView = {
let scrollView = UIScrollView()
scrollView.translatesAutoresizingMaskIntoConstraints = false
return scrollView
}()
stackView = {
let stackView = UIStackView()
stackView.axis = .vertical
stackView.distribution = .fill
stackView.translatesAutoresizingMaskIntoConstraints = false
return stackView
}()
contentView = {
let view = UIView()
view.translatesAutoresizingMaskIntoConstraints = false
return view
}()
contentView.addSubview(stackView)
scrollView.addSubview(contentView)
view.addSubview(scrollView)
scrollView.showsVerticalScrollIndicator = false
scrollView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor).isActive = true
scrollView.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor).isActive = true
scrollView.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor).isActive = true
scrollView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor).isActive = true
contentView.topAnchor.constraint(equalTo: scrollView.topAnchor).isActive = true
contentView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor).isActive = true
contentView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor).isActive = true
contentView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor).isActive = true
contentView.widthAnchor.constraint(equalTo: scrollView.widthAnchor).isActive = true
stackView.topAnchor.constraint(equalTo: contentView.topAnchor, constant: 20).isActive = true
stackView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 20).isActive = true
stackView.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -20).isActive = true
stackView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: -50).isActive = true
Question: How can I animate it in such a way, that it does not change width during the animation?
I don't know if this is a weird issue of the UIStackView or it serves some purpose, but: putting an "invisible" UIView into your UIStackView will fix the issue. Tag it, so when hiding the other elements it remains visible:
let imposterView = UIView()
imposterView.tag = 999
stackView.addArrangedSubview(imposterView)
Of course handle your hiding logic accordingly:
stackView.subviews.forEach({
if $0.tag != 999 {
$0.isHidden = true
}
})
I'm not making progress on this problem for a while now.
I'm trying to add a vertical scroll view to my app with a contentView (UIView). I added the contentView as a subview of the scrollView & added the scrollView as a subview of the main view. After that, I wasn't able to scroll and buttons + the searchbar weren't working anymore. It just felt like the app was frozen.
What I've done so far is the following:
Creating the scroll- and contentView directly in the class
let scrollView:UIScrollView = UIScrollView()
let contentView:UIView = UIView()
Setting up the scrollView
func setupScrollView() {
scrollView.translatesAutoresizingMaskIntoConstraints = false
contentView.translatesAutoresizingMaskIntoConstraints = false
scrollView.contentSize = CGSize(width: self.view.frame.width, height: self.view.frame.height)
// Add scroll view to main view
self.view.addSubview(scrollView)
// Add content to scrollview
scrollView.addSubview(contentView)
// Constraints
scrollView.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive = true
scrollView.widthAnchor.constraint(equalTo: self.view.widthAnchor).isActive = true
scrollView.topAnchor.constraint(equalTo: self.view.topAnchor).isActive = true
contentView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor).isActive = true
contentView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor).isActive = true
scrollView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor).isActive = true
contentView.centerXAnchor.constraint(equalTo: scrollView.centerXAnchor).isActive = true
contentView.widthAnchor.constraint(equalTo: scrollView.widthAnchor).isActive = true
contentView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor).isActive = true
contentView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor).isActive = true
contentView.topAnchor.constraint(equalTo: scrollView.topAnchor).isActive = true
contentView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor).isActive = true
}
Adding several elements as subview to the contentView
// Add search bar to scroll content view
contentView.addSubview(searchBar)
The full code is available on my github repo
I looked through several similar problems and tutorials but somehow can't figure out what's wrong here.
I have a MainViewController with some elements inside. I want the whole view to be vertically scrollable.
I made this BaseScrollableViewController class:
class BaseScrollableViewController: UIViewController, UIScrollViewDelegate {
lazy var scrollView: UIScrollView = {
let scrollView = UIScrollView()
scrollView.delegate = self
scrollView.translatesAutoresizingMaskIntoConstraints = false
scrollView.showsHorizontalScrollIndicator = false
scrollView.showsVerticalScrollIndicator = false
return scrollView
}()
lazy var contentView: UIView = {
let view = UIView()
view.translatesAutoresizingMaskIntoConstraints = false
return view
}()
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(scrollView)
scrollView.addSubview(contentView)
NSLayoutConstraint.activate([
scrollView.topAnchor.constraint(equalTo: view.topAnchor),
scrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
scrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
contentView.topAnchor.constraint(equalTo: scrollView.topAnchor),
contentView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor),
contentView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor),
contentView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor),
contentView.widthAnchor.constraint(equalTo: scrollView.widthAnchor),
contentView.heightAnchor.constraint(equalTo: scrollView.heightAnchor)
])
}
}
Then I made the MainViewController a subclass of this BaseScrollableViewController. Inside, I use contentView to add all the subviews.
Now it scrolls vertically. However, when I scroll down to the bottom, here is what is shows:
Note that there is an empty space at the bottom.
I have tried the scrollView.contentInsetAdjustmentBehavior = .never, but then the scrollView becomes not scrollable.
So how can I fix this? Thanks!
For a scrollView to be scrollable, its subviews need to be bigger than the scrollView. By specifying the following constraint contentView.heightAnchor.constraint(equalTo: scrollView.heightAnchor) on the BaseScrollableViewController you are specifying that the contentView will have the same height of the scrollView, thus making the view not scrollable when setting scrollView.contentInsetAdjustmentBehavior = .never.
You can test this by adding a multiplier value on the contentView height constraint:
contentView.heightAnchor.constraint(equalTo: scrollView.heightAnchor, multiplier: 1.5)
And enabling
`scrollView.contentInsetAdjustmentBehavior = .never`
I'm trying to make a simple layout that should scroll vertically when views are too many to fit on the screen.
So this is what I have so far:
I created a scrollview and a container view like that
let mainScrollView: UIScrollView = {
let scrollView = UIScrollView()
scrollView.isUserInteractionEnabled = true
scrollView.translatesAutoresizingMaskIntoConstraints = false
return scrollView
}()
let containerView: UIView = {
let view = UIView()
view.backgroundColor = .lightGray
view.translatesAutoresizingMaskIntoConstraints = false
return view
}()
Then I added the scrollview to the main view, added the container view to the scrollview and a couple of labels to the container view
view.addSubview(mainScrollView)
mainScrollView.addSubview(containerView)
containerView.addSubview(firstLabel)
containerView.addSubview(secondLabel)
I pinned the scrollview to the main view, and the container view to the scrollview. After that I started adding the labels inside the container view like this
mainScrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
mainScrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
mainScrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
mainScrollView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
containerView.topAnchor.constraint(equalTo: mainScrollView.layoutMarginsGuide.topAnchor).isActive = true
containerView.bottomAnchor.constraint(equalTo: mainScrollView.layoutMarginsGuide.bottomAnchor).isActive = true
containerView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
containerView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
firstLabel.centerXAnchor.constraint(equalTo: containerView.centerXAnchor).isActive = true
firstLabel.topAnchor.constraint(equalTo: containerView.topAnchor, constant: 30).isActive = true
firstLabel.widthAnchor.constraint(equalToConstant: 50).isActive = true
firstLabel.heightAnchor.constraint(equalToConstant: 20).isActive = true
secondLabel.centerXAnchor.constraint(equalTo: containerView.centerXAnchor).isActive = true
secondLabel.topAnchor.constraint(equalTo: firstLabel.bottomAnchor, constant: 750).isActive = true
secondLabel.widthAnchor.constraint(equalToConstant: 50).isActive = true
secondLabel.heightAnchor.constraint(equalToConstant: 20).isActive = true
The problem is that for some reason the scrollview is not able to calculate it's height and it doesn't scroll vertically. The second label remains invisible because it's too "low" on the screen.
I tried setting the bottom constraint of the container view to the bottom of the second label but I'm going nowhere honestly.
What am I missing? How can I set constraints to make the scrollview scroll with autolayout (without setting a specific height of the container view)?
Scrollview scrolls in either direction. So any view added to it would need some additional constraints to let the Scrollview calculate its content size.
You have pinned the container view to scroll view. If you are looking at a vertically scrolling view like a table view then you need to also set the width of the scroll to the container view so that it can calculate the width.
Next for height, its automatically calculated based on the UI elements added in the container view. Ensure that all of the labels have leading, trailing to the container and vertical spacing to each other and top of the container view. This will let the scroll view know the height needed.
self.scrollView.translatesAutoresizingMaskIntoConstraints = false
self.contentView.translatesAutoresizingMaskIntoConstraints = false
self.label1.translatesAutoresizingMaskIntoConstraints = false
self.label2.translatesAutoresizingMaskIntoConstraints = false
self.label3.translatesAutoresizingMaskIntoConstraints = false
self.contentView.addSubview(self.label1)
self.contentView.addSubview(self.label2)
self.contentView.addSubview(self.label3)
self.scrollView.addSubview(self.contentView)
self.view.addSubview(self.scrollView)
NSLayoutConstraint.activate([
self.scrollView.topAnchor.constraint(equalTo: self.view.topAnchor),
self.scrollView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),
self.scrollView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor),
self.scrollView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor)
])
NSLayoutConstraint.activate([
self.contentView.topAnchor.constraint(equalTo: self.scrollView.topAnchor),
self.contentView.trailingAnchor.constraint(equalTo: self.scrollView.trailingAnchor),
self.contentView.bottomAnchor.constraint(equalTo: self.scrollView.bottomAnchor),
self.contentView.leadingAnchor.constraint(equalTo: self.scrollView.leadingAnchor),
self.contentView.widthAnchor.constraint(equalTo: self.scrollView.widthAnchor)
])
NSLayoutConstraint.activate([
self.label1.leadingAnchor.constraint(equalTo: self.contentView.leadingAnchor),
self.label2.leadingAnchor.constraint(equalTo: self.contentView.leadingAnchor),
self.label3.leadingAnchor.constraint(equalTo: self.contentView.leadingAnchor),
self.label1.trailingAnchor.constraint(equalTo: self.contentView.trailingAnchor),
self.label2.trailingAnchor.constraint(equalTo: self.contentView.trailingAnchor),
self.label3.trailingAnchor.constraint(equalTo: self.contentView.trailingAnchor)
])
NSLayoutConstraint.activate([
self.label1.topAnchor.constraint(equalTo: self.contentView.topAnchor),
self.label2.topAnchor.constraint(equalTo: self.label1.bottomAnchor),
self.label3.topAnchor.constraint(equalTo: self.label2.bottomAnchor),
self.label3.bottomAnchor.constraint(equalTo: self.contentView.bottomAnchor)
])
And when run, it won't complain about any constraint issues either. Same can be done for horizontal scroll.
Thank you very much #GoodSp33d, you pointed me to the right direction.
I added the width constraint as you said like that:
containerView.widthAnchor.constraint(equalTo: mainScrollView.widthAnchor).isActive = true
And the key point was to update the bottom constraint after all:
containerView.bottomAnchor.constraint(equalTo: secondLabel.bottomAnchor).isActive = true
Here is the full working code:
mainScrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
mainScrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
mainScrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
mainScrollView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
containerView.topAnchor.constraint(equalTo: mainScrollView.topAnchor).isActive = true
containerView.trailingAnchor.constraint(equalTo: mainScrollView.trailingAnchor).isActive = true
containerView.bottomAnchor.constraint(equalTo: mainScrollView.bottomAnchor).isActive = true
containerView.leadingAnchor.constraint(equalTo: mainScrollView.leadingAnchor).isActive = true
containerView.widthAnchor.constraint(equalTo: mainScrollView.widthAnchor).isActive = true
firstLabel.centerXAnchor.constraint(equalTo: containerView.centerXAnchor).isActive = true
firstLabel.topAnchor.constraint(equalTo: containerView.topAnchor, constant: 30).isActive = true
firstLabel.widthAnchor.constraint(equalToConstant: 50).isActive = true
firstLabel.heightAnchor.constraint(equalToConstant: 20).isActive = true
secondLabel.centerXAnchor.constraint(equalTo: containerView.centerXAnchor).isActive = true
secondLabel.topAnchor.constraint(equalTo: firstLabel.bottomAnchor, constant: 550).isActive = true
secondLabel.widthAnchor.constraint(equalToConstant: 50).isActive = true
secondLabel.heightAnchor.constraint(equalToConstant: 20).isActive = true
containerView.bottomAnchor.constraint(equalTo: secondLabel.bottomAnchor).isActive = true
Thanks for the help.
I am trying to generate views displayed in a UIScrollView based on structured (XML) data at runtime. I generate all the views I need and add them to my scrollview afterwards, using Auto Layout to let the scrollview calculate its contentSize. Everything worked fine as long as I was only using UILabels and a custom UIImageView subclass, but now I want to add a nested view containing another view and a label to represent text with a vertical line on the left side.
The general layout code I'm using to add all generated views to the scrollview is as follows:
var previousAnchor = scrollView.topAnchor
views.forEach { (view) in
scrollView.addSubview(view)
view.translatesAutoresizingMaskIntoConstraints = false
view.topAnchor.constraint(equalTo: previousAnchor,
constant: UI.defaultPadding).isActive = true
view.leadingAnchor.constraint(equalTo: self.view.leadingAnchor,
constant: UI.smallPadding).isActive = true
view.trailingAnchor.constraint(equalTo: self.view.trailingAnchor,
constant: -UI.smallPadding).isActive = true
previousAnchor = view.bottomAnchor
}
scrollView.bottomAnchor.constraint(equalTo: previousAnchor,
constant: UI.defaultPadding).isActive = true
And the layout code for my nested subview looks like this (it's a UIView subclass):
addSubview(label)
addSubview(line)
line.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 10).isActive = true
line.topAnchor.constraint(equalTo: topAnchor).isActive = true
line.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
line.widthAnchor.constraint(equalToConstant: 2).isActive = true
line.trailingAnchor.constraint(equalTo: label.leadingAnchor).isActive = true
line.backgroundColor = UIColor.green
label.topAnchor.constraint(equalTo: topAnchor).isActive = true
label.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
label.trailingAnchor.constraint(equalTo: trailingAnchor).isActive = true
label.numberOfLines = 0
label.text = "Here's to the crazy ones. The misfits. The rebels. The troublemakers."
If I use this code, I cannot see this view in my scrollview at all and the scrollview has a warning of ambiguous content size attached to it in the Debug View Hierarchy view. This is somewhat irritating, as using labels without being nested in a view like this does work like a charm. So I started playing around and what really puzzles me is that if I use the following code I can see the view itself (as I gave it a gray background color), but still can't see line and/or label, as both seem have a frame of (0,0,0,0) upon inspection:
addSubview(label)
addSubview(line)
line.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 10).isActive = true
line.topAnchor.constraint(equalTo: topAnchor, constant: 10).isActive = true
line.widthAnchor.constraint(equalToConstant: 20).isActive = true
line.heightAnchor.constraint(equalToConstant: 20).isActive = true
line.trailingAnchor.constraint(equalTo: label.leadingAnchor).isActive = true
line.backgroundColor = UIColor.green
label.centerYAnchor.constraint(equalTo: centerYAnchor).isActive = true
label.trailingAnchor.constraint(equalTo: trailingAnchor).isActive = true
heightAnchor.constraint(equalToConstant: 100).isActive = true
heightAnchor.constraint(equalTo: label.heightAnchor).isActive = true
label.numberOfLines = 0
label.text = "Here's to the crazy ones. The misfits. The rebels. The troublemakers."
What am I missing? I also tried putting all my views into a container view instead of using them as subviews of the scrollview directly, but this did not help with my nested view and brought up other problems.