I have a tableview and would want to add views dynamically to it, based on the data. For every other view it is easy. Works like charm but collectionview, I don't even see the view on stackview.
The UICollectionView's cellForItem delegate is not called, the numberOfItems delegate is called but not cellForItem.
Not sure if I am missing anything.
func testView() -> UIView {
let containerView = UIView(frame: .zero)
containerView.backgroundColor = .red
let layout = KTCenterFlowLayout()
layout.minimumInteritemSpacing = 10.0
layout.minimumLineSpacing = 10.0
layout.estimatedItemSize = CGSize(width: 80, height: 100)
layout.sectionInset = UIEdgeInsetsMake(20, 30, 20, 30)
let collectionView = UICollectionView(frame: .zero, collectionViewLayout: layout).then {
$0.dataSource = self
$0.isScrollEnabled = false
$0.setCollectionViewLayout(layout, animated: false)
$0.register(NPSCollectionViewCell.self, forCellWithReuseIdentifier: "npsCell")
$0.contentSize = CGSize(width: view.frame.size.width-100, height: 500.0)
containerView.addSubview($0)
}
collectionView.snp.makeConstraints { (make) in
make.edges.equalToSuperview()
make.height.equalTo(500).priority(500)
}
return containerView
}
I am adding this above view in CellForRowAtIndexPath in
cell?.stackView.addArrangedSubview(testView())
Any pointers?
Edit: here is the screenshot
I just see a blank space
Here is my StackTableViewCell
lazy var stackView : UIStackView! = {
let stack = UIStackView()
stack.axis = .vertical
stack.distribution = .fillProportionally
stack.alignment = .center
stack.spacing = 10.0
stack.translatesAutoresizingMaskIntoConstraints = false
stack.setContentCompressionResistancePriority(UILayoutPriority.required, for: .vertical)
return stack
}()
override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
contentView.addSubview(stackView)
stackView.snp.makeConstraints { (make) in
make.top.equalToSuperview().offset(10)
make.left.equalToSuperview().offset(20)
make.right.equalToSuperview().offset(-20)
make.bottom.equalToSuperview().offset(-10)
}
I had a problem that the cell wasn't displaying and I just gave it a size manually using a property of the collectionView try this approach
Related
I'm making an app with UIkit and I'm making some UITableViewCells that contain an array of user images. I want these images to be displayed in a horizontal stack and overlay each other.
This is how I want it to look:
That's how it looks:
Code:
import UIKit
import SDWebImage
class CountryTableCell: UITableViewCell {
static let reuseIdentifier = "CountryTableCell"
//MARK: - Propeties
var viewModel: CountryViewModel? {
didSet {
viewModel?.delegate = self
setUpSpace(viewModel)
}
}
//MARK: - SubViews
private let container: UIView = {
let view = UIView()
view.withSize(CGSize(width: Dimensions.maxSafeWidth, height: 150))
view.backgroundColor = .secondary_background
view.layer.cornerRadius = 20
return view
}()
private let adminsContainer: UIView = {
let view = UIView()
view.withSize(CGSize(width: (Dimensions.maxSafeWidth - 32), height: Dimensions.image.mediumHeigthWithOverlay))
view.backgroundColor = .secondary_background
return view
}()
private let adminsStack: UIStackView = {
let stack = UIStackView()
stack.axis = .horizontal
stack.alignment = .leading
stack.spacing = -10
stack.sizeToFit()
stack.distribution = .fillEqually
stack.withSize(CGSize(width: Dimensions.image.mediumHeigthWithOverlay, height: Dimensions.image.mediumHeigthWithOverlay))
return stack
}()
private let nameLabel: UILabel = {
let label = UILabel()
label.font = .systemFont(ofSize: UIFont.preferredFont(forTextStyle: .title2).pointSize, weight: .bold)
label.textColor = .primary_label
label.textAlignment = .left
label.sizeToFit()
label.numberOfLines = 0
return label
}()
var headerView: UIImageView = {
let iv = UIImageView()
iv.contentMode = .scaleAspectFill
iv.clipsToBounds = true
iv.withSize(CGSize(width: Dimensions.image.headerSizeForCell.width, height: ((Dimensions.image.mediumHeigth/2) + Padding.horizontal)))
iv.backgroundColor = .secondary_background
iv.layer.maskedCorners = [.layerMaxXMinYCorner, .layerMinXMinYCorner]
iv.layer.cornerRadius = 20
return iv
}()
//MARK: - Init
override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
addSubview(container)
container.center(inView: self)
addSubview(headerView)
headerView.anchor(top: container.topAnchor, left: container.leftAnchor, right: container.rightAnchor)
addSubview(nameLabel)
nameLabel.anchor(top: headerView.bottomAnchor, left: container.leftAnchor, right: container.rightAnchor, paddingLeft: Padding.horizontal, paddingRight: Padding.horizontal)
addSubview(adminsContainer)
adminsContainer.anchor(left: container.leftAnchor, bottom: headerView.bottomAnchor, right: container.rightAnchor ,paddingLeft: Padding.horizontal, paddingBottom: -(Dimensions.image.mediumHeigth/2), paddingRight: Padding.horizontal)
bringSubviewToFront(adminsContainer)
adminsContainer.backgroundColor = .clear.withAlphaComponent(0.0)
adminsContainer.addSubview(adminsStack)
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
//MARK: - Lifecycle
override func willRemoveSubview(_ subview: UIView) {
}
//MARK: Selectors
//MARK: - Helpers
private func setUpSpace(_ viewModel: CountryViewModel?) {
guard let viewModel = viewModel else {return}
if let url = viewModel.country.headerImage?.url {
headerView.sd_setImage(with: URL(string: url))
}
nameLabel.text = viewModel.space.name
}
}
// MARK: Extension
extension SpaceTableCell: CountryViewModelDelegate {
func didFetchAdmin(_ admin: User) {
if let admins = viewModel?.admins.count {
if admins == 1 {
adminsStack.withSize(CGSize(width: Dimensions.image.mediumHeigthWithOverlay, height: Dimensions.image.mediumHeigthWithOverlay))
} else if admins == 2 {
adminsStack.withSize(CGSize(width: ((Dimensions.image.mediumHeigthWithOverlay*2) - 10), height: Dimensions.image.mediumHeigthWithOverlay))
} else if admins == 3 {
adminsStack.withSize(CGSize(width: ((Dimensions.image.mediumHeigthWithOverlay*3) - 20), height: Dimensions.image.mediumHeigthWithOverlay))
} else if admins == 4 {
adminsStack.withSize(CGSize(width: ((Dimensions.image.mediumHeigthWithOverlay*4) - 30), height: Dimensions.image.mediumHeigthWithOverlay))
} else if admins == 5 {
adminsStack.withSize(CGSize(width: ((Dimensions.image.mediumHeigthWithOverlay*5) - 40), height: Dimensions.image.mediumHeigthWithOverlay))
}
}
let image = UserImageView(height: Dimensions.image.mediumHeigth)
image.sd_setImage(with: admin.profileImageURL)
adminsStack.addArrangedSubview(image)
}
}
class UserImageView: UIImageView {
//MARK: - Propeties
let selectedHeigth: CGFloat
init(height: CGFloat) {
self.selectedHeigth = height
super.init(frame: CGRect(x: 0, y: 0, width: selectedHeigth, height: selectedHeigth))
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func layoutSubviews() {
super.layoutSubviews()
contentMode = .scaleAspectFill
clipsToBounds = true
backgroundColor = .secondary_background
layer.cornerRadius = Dimensions.userImageCornerRadious(selectedHeigth)
}
}
Can someone please help me
Thank you :)
I'd suggest a couple changes:
Change #1:
Your UIStackView's distribution set to .fillEqually. By doing this, you're giving it the permission to stretch its arrangedSubviews as and when needed to fit the width that you've provided. This does prove useful in some cases but in your case, it's better to go with .fill instead
Here's an excerpt from Apple's documentation:
For all distributions except the UIStackView.Distribution.fillEqually
distribution, the stack view uses each arranged view’s
intrinsicContentSize property when calculating its size along the
stack’s axis. UIStackView.Distribution.fillEqually resizes all the
arranged views so they’re the same size, filling the stack view along
its axis. If possible, the stack view stretches all the arranged views
to match the view with the longest intrinsic size along the stack’s
axis.
I suggest that you go through this documentation and read more about this
Change #2:
Since you've now changed the distribution to respect intrinsic size, don't set up constraints that conflict with UIStackView's distribution axis. In your case, you have a horizontal stack view and seem to be also defining its width constraints based on the number of admins you have. I'd suggest getting rid of it and leave it to your stack view to take care of it.
One more pointer:
Make sure your UserImageViews have proper unified intrinsicContentSize i.e: the images you set follow the same size. If doubtful, I'd suggest setting up constraints for its width and height respectively. To do so, in your UserImageView's init, include:
self.widthAnchor.constraint(equalToConstant: height).isActive = true
self.heightAnchor.constraint(equalToConstant: height).isActive = true
I have this viewController:
class CreateSkillGroupViewController: UIViewController {
lazy var headerStack: UIStackView = {
let stack = UIStackView(frame: CGRect(x: 0, y: 0, width: 20, height: 400))
stack.axis = .vertical
let titleField = UITextView(frame: CGRect(x: 0, y: 0, width: 300, height: 88))
titleField.backgroundColor = .green
titleField.snp.makeConstraints{ (make) in
make.height.equalTo(50)
}
let descriptionField = UITextView(frame: CGRect(x: 0, y: 0, width: 300, height: 120))
descriptionField.snp.makeConstraints{ (make) in
make.height.equalTo(100)
}
let headerImage = UIImageView(image: UIImage(named: "AppIcon-bw"))
headerImage.snp.makeConstraints{ (make) in
make.height.equalTo(300)
make.width.equalTo(200)
}
stack.addArrangedSubview(headerImage)
stack.addArrangedSubview(titleField)
stack.addArrangedSubview(descriptionField)
stack.backgroundColor = .blue
return stack
}()
override func viewDidLoad() {
super.viewDidLoad()
configureNavigationItem()
skillsTableView = UITableView(frame: .zero, style: .insetGrouped)
skillsTableView.register(SkillSummaryCell.self)
skillsTableView.tableHeaderView = headerStack
view.addSubview(skillsTableView)
skillsTableView.tableHeaderView?.snp.makeConstraints{ (make) in
make.top.equalToSuperview()
make.left.equalToSuperview()
make.right.equalToSuperview()
make.width.equalToSuperview()
make.height.equalTo(400)
}
skillsTableView.snp.makeConstraints{ (make) in
make.edges.equalToSuperview()
}
...
This is what it creates...
As you can see I use the lazy var headerStack to setup the tableHeaderView which is a stackView. As you can see all of the constraints in that stack view are explicit number sizes. Then in the viewDidLoad, I add the constraints for the tableView itself.
I want to know how I would for instance, center the headerImage in the viewController, or in the tableView for that matter or make its width half of the tableView's width. I cannot set equalToSuperView because the view hasn't been laid out yet. And once its laid out, I cannot access the stack view subviews to retroactively add constraints to them.
First of all, I wouldn't use a stackView as a tableHeaderView because you need your tableHeaderView to be the same width as the tableView. Embed your stackView in a view and use that view as the header. Ensure that header remains the width of the tableView regardless of the stackView content.
Also, it looks like you are trying to mix autolayout with frame-based layout and that's gonna get you into trouble. I'm not sure why you were setting frames on some of your subviews.
Pay attention to how you define stackView.alignment and stackView.distribution. I'm not sure what your goal is so it's hard to give you much advice there. Bit I assume you want your subviews centered and to have their own unique width.
You defined a lot of your subviews in your stackView builder and that got you into trouble. Ensure that you have one builder for each subview. It helps keep your code clean.
Lastly, you can use autolayout to define the width equal to the width of the tableView. There are a lot of solutions on the web that make you compute the frames for your header manually and that's just a pain.
I changed some names around added some colors but I think this will help you:
extension UIColor {
static let headerImage = UIColor.systemPurple
static let header = UIColor.systemPink
static let titleField = UIColor.white
static let descriptionField = UIColor.systemYellow
static let headerStack = UIColor.systemOrange
static let tableView = UIColor.systemMint
}
class ViewController: UIViewController {
lazy var headerImage: UIImageView = {
let headerImage = UIImageView(image: UIImage(systemName: "checkmark"))
headerImage.translatesAutoresizingMaskIntoConstraints = false
headerImage.backgroundColor = .headerImage
return headerImage
}()
lazy var headerView: UIView = {
let header = UIView()
header.backgroundColor = .header
header.translatesAutoresizingMaskIntoConstraints = false
return header
}()
lazy var titleField: UITextView = {
let titleField = UITextView(frame: .zero)
titleField.translatesAutoresizingMaskIntoConstraints = false
titleField.backgroundColor = .titleField
return titleField
}()
lazy var descriptionField: UITextView = {
let descriptionField = UITextView(frame: .zero)
descriptionField.translatesAutoresizingMaskIntoConstraints = false
descriptionField.backgroundColor = .descriptionField
return descriptionField
}()
lazy var headerStack: UIStackView = {
let stack = UIStackView(frame: .zero)
stack.translatesAutoresizingMaskIntoConstraints = false
stack.axis = .vertical
stack.distribution = .fillProportionally
stack.alignment = .center
stack.spacing = 10
stack.backgroundColor = .headerStack
return stack
}()
lazy var tableView: UITableView = {
let tableView = UITableView(frame: .zero, style: .insetGrouped)
tableView.translatesAutoresizingMaskIntoConstraints = false
tableView.register(SkillSummaryCell.self, forCellReuseIdentifier: "SkillSummaryCell")
tableView.backgroundColor = .tableView
tableView.delegate = self
tableView.dataSource = self
return tableView
}()
override func viewDidLoad() {
super.viewDidLoad()
addViews()
arrangeViews()
tableView.layoutIfNeeded()
}
func addViews() {
view.addSubview(tableView)
headerStack.addArrangedSubview(headerImage)
headerStack.addArrangedSubview(titleField)
headerStack.addArrangedSubview(descriptionField)
headerView.addSubview(headerStack)
tableView.tableHeaderView = headerView
}
func arrangeViews() {
tableView.snp.makeConstraints{ (make) in
make.edges.equalTo(view.safeAreaLayoutGuide)
}
descriptionField.snp.makeConstraints{ (make) in
make.height.equalTo(100)
make.width.equalTo(300)
}
titleField.snp.makeConstraints{ (make) in
make.height.equalTo(100)
make.width.equalTo(300)
}
headerStack.snp.makeConstraints { make in
make.top.equalToSuperview()
make.bottom.equalToSuperview()
make.centerX.equalToSuperview()
}
headerView.snp.makeConstraints { make in
make.width.equalTo(tableView)
}
headerImage.snp.makeConstraints{ (make) in
make.width.equalTo(tableView).dividedBy(2)
make.height.equalTo(headerImage.snp.width)
}
}
}
use it:
viewForHeaderInSection
as
func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
let tableBounds = tableView.bounds // <- table size
let sectionIndex = section // <- Section index
}
In this method, you can customize the header for a specific section, and take into account the size of your table
ALSO:
You can use UIScreen.main.bounds - get the screen size of your phone at any time, this can be very useful, especially considering that tables are often equal in width to the width of the screen
I am trying to resize my UIImageView as a circle, however; every time I try to resize the UIImageView, which is inside a StackView along with the UILabel, I keep on ending up with a more rectangular shape. Can someone show me where I am going wrong I have been stuck on this for days? Below is my code, and what it's trying to do is add the image with the label at the bottom, and the image is supposed to be round, and this is supposed to be for my collection view controller.
custom collection view cell
import UIKit
class CarerCollectionViewCell: UICollectionViewCell {
static let identifier = "CarerCollectionViewCell"
private let imageView: UIImageView = {
let imageView = UIImageView()
imageView.frame = CGRect(x: 0, y: 0, width: 20, height: 20);
//imageView.center = imageView.superview!.center;
imageView.contentMode = .scaleAspectFill
imageView.layer.borderWidth = 4
imageView.layer.masksToBounds = false
imageView.layer.borderColor = UIColor.orange.cgColor
imageView.layer.cornerRadius = imageView.frame.height / 2
return imageView
}()
private let carerNamelabel: UILabel = {
let carerNamelabel = UILabel()
carerNamelabel.layer.masksToBounds = false
carerNamelabel.font = .systemFont(ofSize: 12)
carerNamelabel.textAlignment = .center
carerNamelabel.layer.frame = CGRect(x: 0, y: 0, width: 50, height: 50);
return carerNamelabel
}()
private let stackView: UIStackView = {
let stackView = UIStackView()
stackView.layer.masksToBounds = false
stackView.axis = .vertical
stackView.alignment = .center
stackView.backgroundColor = .systemOrange
stackView.distribution = .fillProportionally
stackView.translatesAutoresizingMaskIntoConstraints = false
return stackView
}()
override init(frame: CGRect) {
super.init(frame: frame)
configureContentView()
}
required init?(coder: NSCoder) {
super.init(coder: coder)
}
private func configureContentView() {
imageView.clipsToBounds = true
stackView.clipsToBounds = true
carerNamelabel.clipsToBounds = true
contentView.addSubview(stackView)
configureStackView()
}
private func configureStackView() {
allContraints()
stackView.addArrangedSubview(imageView)
stackView.addArrangedSubview(carerNamelabel)
}
private func allContraints() {
setStackViewConstraint()
}
private func setStackViewConstraint() {
stackView.widthAnchor.constraint(equalTo: contentView.widthAnchor).isActive = true
stackView.heightAnchor.constraint(equalTo: contentView.heightAnchor).isActive = true
stackView.centerXAnchor.constraint(equalTo: contentView.centerXAnchor).isActive = true
stackView.centerYAnchor.constraint(equalTo: contentView.centerYAnchor).isActive = true
}
public func configureImage(with imageName: String, andImageName labelName: String) {
imageView.image = UIImage(named: imageName)
carerNamelabel.text = labelName
}
override func layoutSubviews() {
super.layoutSubviews()
stackView.frame = contentView.bounds
}
override func prepareForReuse() {
super.prepareForReuse()
imageView.image = nil
carerNamelabel.text = nil
}
}
Below here is my code for the CollectionViewControler
custom collection view
import UIKit
class CarerViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
private var collectionView: UICollectionView = {
let layout = UICollectionViewFlowLayout()
layout.scrollDirection = .vertical
layout.itemSize = CGSize(width: 120, height: 120)
let collectionView = UICollectionView(frame: .zero, collectionViewLayout: layout)
collectionView.register(CarerCollectionViewCell.self, forCellWithReuseIdentifier: CarerCollectionViewCell.identifier)
collectionView.showsVerticalScrollIndicator = false
collectionView.backgroundColor = .clear
return collectionView
}()
override func viewDidLoad() {
super.viewDidLoad()
collectionView.delegate = self
collectionView.dataSource = self
view.addSubview(collectionView)
collectionView.translatesAutoresizingMaskIntoConstraints = false
// Layout constraints for `collectionView`
NSLayoutConstraint.activate([
collectionView.widthAnchor.constraint(equalTo: view.widthAnchor),
collectionView.heightAnchor.constraint(lessThanOrEqualTo: view.heightAnchor, constant: 600),
collectionView.topAnchor.constraint(equalTo: view.topAnchor, constant: 200),
collectionView.leadingAnchor.constraint(equalTo: view.leadingAnchor)
])
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 10
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: CarerCollectionViewCell.identifier, for: indexPath) as! CarerCollectionViewCell
cell.configureImage(with: "m7opt04g_ms-dhoni-afp_625x300_06_July_20", andImageName: "IMAGE NO. 1")
return cell
}
}
Can somebody show or point to me what I am doing wrong, thank you
This is what I am trying to achieve
UIStackView could be tricky sometimes, you can embed your UIImageView in a UIView, and move your layout code to viewWillLayoutSubviews(), this also implys for the UILabel embed that also inside a UIView, so the containers UIViews will have a static frame for the UIStackViewto be layout correctly and whats inside them will only affect itself.
I am implementing a UIScrollView in a CollectionViewCell. I have a custom view which the scroll view should display, hence I am performing the following program in the CollectionViewCell. I have created everything programmatically and below is my code :
struct ShotsCollections {
let title: String?
}
class ShotsMainView: UICollectionViewCell {
override init(frame: CGRect) {
super.init(frame: frame)
setupViews()
containerScrollView.contentSize.width = frame.width * CGFloat(shotsData.count)
shotsData = [ShotsCollections.init(title: "squad"), ShotsCollections.init(title: "genral")]
var i = 0
for data in shotsData {
let customview = ShotsMediaView(frame: CGRect(x: containerScrollView.frame.width * CGFloat(i), y: 0, width: containerScrollView.frame.width, height: containerScrollView.frame.height))
containerScrollView.addSubview(customview)
i += 1
}
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
var shotsData = [ShotsCollections]()
var containerScrollView: UIScrollView = {
let instance = UIScrollView()
instance.isScrollEnabled = true
instance.bounces = true
instance.backgroundColor = blueColor
return instance
}()
private func setupViews() { //These are constraints by using TinyConstraints
addSubview(containerScrollView)
containerScrollView.topToSuperview()
containerScrollView.bottomToSuperview()
containerScrollView.rightToSuperview()
containerScrollView.leftToSuperview()
}
}
Now the issue is, while the scrollview is displayed, the content in it is not. I on printing the contentSize and frame of the scrollview, it displays 0. But if I check the Debug View Hierarchy, scrollview containes 2 views with specific frames.
I am not sure whats going wrongs. Any help is appreciated.
When you are adding customView in your containerScrollView, you are not setting up the constraints between customView and containerScrollView.
Add those constraints and you will be able to see your customViews given that your customView has some height. Also, when you add more view, you would need to remove the bottom constraint of the last added view and create a bottom constraint to the containerScrollView with the latest added view.
I created a sample app for your use case. I am pasting the code and the resultant screen shot below. Hope this is the functionality you are looking for. I suggest you paste this in a new project and tweak the code until you are satisfied. I have added comments to make it clear.
ViewController
import UIKit
class ViewController: UIViewController {
// Initialize dummy data array with numbers 0 to 9
var data: [Int] = Array(0..<10)
override func loadView() {
super.loadView()
// Add collection view programmatically
let collectionView = UICollectionView(frame: .zero, collectionViewLayout: UICollectionViewFlowLayout())
collectionView.translatesAutoresizingMaskIntoConstraints = false
collectionView.register(ShotsMainView.self, forCellWithReuseIdentifier: ShotsMainView.identifier)
self.view.addSubview(collectionView)
NSLayoutConstraint.activate([
self.view.topAnchor.constraint(equalTo: collectionView.topAnchor),
self.view.bottomAnchor.constraint(equalTo: collectionView.bottomAnchor),
self.view.leadingAnchor.constraint(equalTo: collectionView.leadingAnchor),
self.view.trailingAnchor.constraint(equalTo: collectionView.trailingAnchor),
])
collectionView.delegate = self
collectionView.dataSource = self
collectionView.translatesAutoresizingMaskIntoConstraints = false
collectionView.backgroundColor = UIColor.white
self.view.addSubview(collectionView)
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
self.view.backgroundColor = UIColor.white
}
}
extension ViewController: UICollectionViewDelegate, UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 10
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: ShotsMainView.identifier, for: indexPath) as! ShotsMainView
return cell
}
}
extension ViewController: UICollectionViewDelegateFlowLayout {
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
// The cell dimensions are set from here
return CGSize(width: collectionView.frame.size.width, height: 100.0)
}
}
ShotsMainView
This is the collection view cell
import UIKit
class ShotsMainView: UICollectionViewCell {
static var identifier = "Cell"
weak var textLabel: UILabel!
override init(frame: CGRect) {
// Initialize with zero frame
super.init(frame: frame)
// Add the scrollview and the corresponding constraints
let containerScrollView = UIScrollView(frame: .zero)
containerScrollView.isScrollEnabled = true
containerScrollView.bounces = true
containerScrollView.backgroundColor = UIColor.blue
containerScrollView.translatesAutoresizingMaskIntoConstraints = false
self.addSubview(containerScrollView)
NSLayoutConstraint.activate([
self.topAnchor.constraint(equalTo: containerScrollView.topAnchor),
self.bottomAnchor.constraint(equalTo: containerScrollView.bottomAnchor),
self.leadingAnchor.constraint(equalTo: containerScrollView.leadingAnchor),
self.trailingAnchor.constraint(equalTo: containerScrollView.trailingAnchor)
])
// Add the stack view that will hold the individual items that
// in each row that need to be scrolled horrizontally
let stackView = UIStackView(frame: .zero)
stackView.distribution = .fill
stackView.translatesAutoresizingMaskIntoConstraints = false
stackView.axis = .horizontal
containerScrollView.addSubview(stackView)
stackView.backgroundColor = UIColor.magenta
NSLayoutConstraint.activate([
containerScrollView.leadingAnchor.constraint(equalTo: stackView.leadingAnchor),
containerScrollView.trailingAnchor.constraint(equalTo: stackView.trailingAnchor),
containerScrollView.topAnchor.constraint(equalTo: stackView.topAnchor),
containerScrollView.bottomAnchor.constraint(equalTo: stackView.bottomAnchor)
])
// Add individual items (Labels in this case).
for i in 0..<10 {
let label = UILabel(frame: .zero)
label.translatesAutoresizingMaskIntoConstraints = false
stackView.addArrangedSubview(label)
label.text = "\(i)"
label.font = UIFont(name: "System", size: 20.0)
label.textColor = UIColor.white
label.backgroundColor = UIColor.purple
label.layer.masksToBounds = false
label.layer.borderColor = UIColor.white.cgColor
label.layer.borderWidth = 1.0
label.textAlignment = .center
NSLayoutConstraint.activate([
label.heightAnchor.constraint(equalTo: self.heightAnchor, multiplier: 1.0, constant: 0.0),
label.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 0.2, constant: 0.0)
])
}
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
Screenshot
I'm trying to achieve the stackView arrangement shown in the middle of this figure:, but for some reason the top stack, containing a collectionView, disappears when using: a .fill distribution
stackView.distribution = .fill (stack containing collectionView disappears)
stackView.distribution = .fillEqually (collectionView appears fine in stackView)
I've been struggling with this for days, and you'll see residues in my commented out sections: setting compressionResistance/hugging priorities, attempting to change the intrinsic height, changing .layout.itemSize of UICollectionViewFlowLayout(), etc... Nothing works in my hands. The code here will run if you simply paste it in and associate it with an empty UIViewController. The top, collectionView stack contains a pickerView, and the stacks below that are a pageControllView, subStack of buttons, and a UIView. It all works fine in the .fillEqually distribution, so this is purely a layout issue. Much Thanks!
// CodeStackVC2
// Test of programmatically generated stack views
// Output: nested stack views
// To make it run:
// 1) Assign the blank storyboard VC as CodeStackVC2
// 2) Move the "Is Inital VC" arrow to the blank storyboard
import UIKit
class CodeStackVC2: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate,UICollectionViewDelegateFlowLayout, UIGestureRecognizerDelegate {
let fruit = ["Apple", "Orange", "Plum", "Qiwi", "Banana"]
let veg = ["Lettuce", "Carrot", "Celery", "Onion", "Brocolli"]
let meat = ["Beef", "Chicken", "Ham", "Lamb"]
let bread = ["Wheat", "Muffin", "Rye", "Pita"]
var foods = [[String]]()
let button = ["bread","fruit","meat","veg"]
var sView = UIStackView()
let cellId = "cellId"
override func viewDidLoad() {
super.viewDidLoad()
foods = [fruit, veg, meat, bread]
setupViews()
}
//MARK: Views
lazy var cView: UICollectionView = {
let layout = UICollectionViewFlowLayout()
layout.scrollDirection = .horizontal
layout.minimumLineSpacing = 0
layout.sectionInset = UIEdgeInsets(top: 5, left: 5, bottom: 5, right: 5)
layout.itemSize = CGSize(width: self.view.frame.width, height: 120)
let cv = UICollectionView(frame: self.view.frame, collectionViewLayout: layout)
cv.backgroundColor = UIColor.lightGray
cv.isPagingEnabled = true
cv.dataSource = self
cv.delegate = self
cv.isUserInteractionEnabled = true
// var intrinsicContentSize: CGSize {
// return CGSize(width: UIViewNoIntrinsicMetric, height: 120)
// }
return cv
}()
lazy var pageControl: UIPageControl = {
let pageC = UIPageControl()
pageC.numberOfPages = self.foods.count
pageC.pageIndicatorTintColor = UIColor.darkGray
pageC.currentPageIndicatorTintColor = UIColor.white
pageC.backgroundColor = .lightGray
pageC.addTarget(self, action: #selector(changePage(sender:)), for: UIControlEvents.valueChanged)
// pageC.setContentHuggingPriority(900, for: .vertical)
// pageC.setContentCompressionResistancePriority(100, for: .vertical)
return pageC
}()
var readerView: UIView = {
let rView = UIView()
rView.backgroundColor = UIColor.brown
// rView.setContentHuggingPriority(100, for: .vertical)
// rView.setContentCompressionResistancePriority(900, for: .vertical)
return rView
}()
func makeButton(_ name:String) -> UIButton{
let newButton = UIButton(type: .system)
let img = UIImage(named: name)?.withRenderingMode(.alwaysTemplate)
newButton.setImage(img, for: .normal)
newButton.contentMode = .scaleAspectFit
newButton.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleButton)))
newButton.isUserInteractionEnabled = true
newButton.backgroundColor = .orange
return newButton
}
//Make a 4-item vertical stackView containing
//cView,pageView,subStackof 4-item horiz buttons, readerView
func setupViews(){
cView.register(FoodCell.self, forCellWithReuseIdentifier: cellId)
//generate an array of buttons
var buttons = [UIButton]()
for i in 0...foods.count-1 {
buttons += [makeButton(button[i])]
}
let subStackView = UIStackView(arrangedSubviews: buttons)
subStackView.axis = .horizontal
subStackView.distribution = .fillEqually
subStackView.alignment = .center
subStackView.spacing = 20
//set up the stackView
let stackView = UIStackView(arrangedSubviews: [cView,pageControl,subStackView,readerView])
stackView.axis = .vertical
//.fillEqually works, .fill deletes cView, .fillProportionally & .equalSpacing delete cView & readerView
stackView.distribution = .fillEqually
stackView.alignment = .fill
stackView.spacing = 5
//Add the stackView using AutoLayout
view.addSubview(stackView)
stackView.translatesAutoresizingMaskIntoConstraints = false
stackView.topAnchor.constraint(equalTo: view.topAnchor, constant: 5).isActive = true
stackView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
stackView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
stackView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
}
func handleButton() {
print("button pressed")
}
//pageControl page changer
func changePage(sender: AnyObject) -> () {
let x = CGFloat(pageControl.currentPage) * cView.frame.size.width
cView.setContentOffset(CGPoint(x:x, y:0), animated: true)
}
//MARK: horizontally scrolling Chapter collectionView
func scrollViewDidScroll(_ scrollView: UIScrollView) {
// let scrollBarLeft = CGFloat(scrollView.contentOffset.x) / CGFloat(book.chap.count + 1)
// let scrollBarWidth = CGFloat( menuBar.frame.width) / CGFloat(book.chap.count + 1)
}
func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
let index = targetContentOffset.pointee.x / view.frame.width
pageControl.currentPage = Int(index) //change PageControl indicator
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return foods.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! FoodCell
cell.foodType = foods[indexPath.item]
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: view.frame.width, height: 120)
}
}
class FoodCell:UICollectionViewCell, UIPickerViewDelegate, UIPickerViewDataSource {
var foodType: [String]? {
didSet {
pickerView.reloadComponent(0)
pickerView.selectRow(0, inComponent: 0, animated: true)
}
}
lazy var pickerView: UIPickerView = {
let pView = UIPickerView()
pView.frame = CGRect(x:0,y:0,width:Int(pView.bounds.width), height:Int(pView.bounds.height))
pView.delegate = self
pView.dataSource = self
pView.backgroundColor = .darkGray
return pView
}()
override init(frame: CGRect) {
super.init(frame: frame)
setupViews()
}
func setupViews() {
backgroundColor = .clear
addSubview(pickerView)
addConstraintsWithFormat("H:|[v0]|", views: pickerView)
addConstraintsWithFormat("V:|[v0]|", views: pickerView)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
if let count = foodType?.count {
return count
} else {
return 0
}
}
func pickerView(_ pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusing view: UIView?) -> UIView {
let pickerLabel = UILabel()
pickerLabel.font = UIFont.systemFont(ofSize: 15)
pickerLabel.textAlignment = .center
pickerLabel.adjustsFontSizeToFitWidth = true
if let foodItem = foodType?[row] {
pickerLabel.text = foodItem
pickerLabel.textColor = .white
return pickerLabel
} else {
print("chap = nil in viewForRow")
return UIView()
}
}
}
The problem is that you have a stack view with a fixed height that contains two views (cView and readerView) that have no intrinsic content size. You need to tell the layout engine how it should size those views to fill the remaining space in the stack view.
It works when you use a .fillEqually distribution because you are telling the layout engine to make all four views in the stack view have an equal height. That defines a height for both the cView and readerView.
When you use a .fill distribution there is no way to determine how high the cView and readerView should be. The layout is ambiguous until you add more constraints. The content priorities do nothing as those views have no intrinsic size that can be stretched or squeezed. You need to set the height of one of the views with no intrinsic size and the other will take the remaining space.
The question is how high should the collection view be? Do you want it to be the same size as the reader view or maybe some proportion of the container view?
For example, suppose your design calls for the collection view to be 25% of the height of the container view with the readerView using the remaining space (the two other views are at their natural intrinsic content size). You could add the following constraint:
NSLayoutConstraint.activate([
cView.heightAnchor.constraint(equalTo: view.heightAnchor, multiplier: 0.25)
])
A Simpler Example
To reduce the layout to its most basic elements. You have a stack view pinned to its superview with four arranged subviews two of which have no intrinsic content size. For example, here is a view controller with two plain UIView, a label and a button:
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
setupViews()
}
private func setupViews() {
let blueView = UIView()
blueView.backgroundColor = .blue
let titleLabel = UILabel()
titleLabel.text = "Hello"
let button = UIButton(type: .system)
button.setTitle("Action", for: .normal)
let redView = UIView()
redView.backgroundColor = .red
let stackView = UIStackView(arrangedSubviews: [blueView, titleLabel, button, redView])
stackView.translatesAutoresizingMaskIntoConstraints = false
stackView.axis = .vertical
stackView.spacing = 8
view.addSubview(stackView)
NSLayoutConstraint.activate([
stackView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
stackView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
stackView.topAnchor.constraint(equalTo: topLayoutGuide.bottomAnchor),
stackView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
blueView.heightAnchor.constraint(equalTo: view.heightAnchor, multiplier: 0.25)
])
}
}
Here is how it looks on an iPhone in portrait with the blue view using 25% of the vertical space:
UIStackView works well with arranged subviews that are UIView but not directly with UICollectionView.
I suggest you put all your subviews items inside a UIView before stack them in a UIStackView, also you can use .fill distribution without use intrinsic content size, use instead constraints to make your subviews proportional as you need.
This solution also work seamless with autolayout without force translatesAutoresizingMaskIntoConstraints = false which make you less compliant with trait changes if you know what I mean.
/GM
Set the top, bottom, leading and trailing constraint of desired controls inside xib or storyboard.
Provide distribution of stack .fill.
Then provide height constraint of all stacks in Xib or storyboard.
Then set appropriate heights for every stacks inside code.
Hopefully it works for you.
I had the same issue, and for me it worked when I gave height and width constraints to the collection view which was placed inside the stack view.
I experienced this behavior with Xamarin CollectionView and tracked it down to an interaction being made with the CollectionView after the page was removed from the MainPage as the result of a web api call. Even blocking that, though it still had issues reloading the page. I finally resolved to clearing the collection list when the page is about to be hidden and saving a backup copy of the items, then on display of the page, running an async task that waited 10ms and then reinstalled the items. Failing to clear the list or installing items into the list immediately upon redisplay both leads to the error. The following shows in the console list and the CollectionView seems to flag itself to longer try to work after this message:
2022-04-16 19:56:33.760310-0500 .iOS[30135:2117558] The behavior of the UICollectionViewFlowLayout is not defined because:
2022-04-16 19:56:33.760454-0500 .iOS[30135:2117558] the item width must be less than the width of the UICollectionView minus the section insets left and right values, minus the content insets left and right values.
2022-04-16 19:56:33.760581-0500 .iOS[30135:2117558] Please check the values returned by the delegate.
2022-04-16 19:56:33.760754-0500 .iOS[30135:2117558] The relevant UICollectionViewFlowLayout instance is <Xamarin_Forms_Platform_iOS_ListViewLayout: 0x7f99e4c4e890>, and it is attached to <UICollectionView: 0x7f99e562a000; frame = (0 0; 420 695); clipsToBounds = YES; autoresize = W+H; gestureRecognizers = <NSArray: 0x6000015ad9b0>; layer = <CALayer: 0x600005be5860>; contentOffset: {0, 0}; contentSize: {0, 0}; adjustedContentInset: {0, 0, 0, 0}; layout: <Xamarin_Forms_Platform_iOS_ListViewLayout: 0x7f99e4c4e890>; dataSource: <Xamarin_Forms_Platform_iOS_GroupableItemsViewController_1: 0x7f99e4c7ace0>>.
2022-04-16 19:56:33.760829-0500 .iOS[30135:2117558] Make a symbolic breakpoint at UICollectionViewFlowLayoutBreakForInvalidSizes to catch this in the debugger.