Dynamically resize UITableViewCell at runtime on tvOS - swift

Question

I currently have a UIViewController with the following hierarchy:
UIViewController
-- UIView
---- UITableView
------ UITableViewCell
-------- UICollectionView
---------- UICollectionViewCell
-------- UIView
---------- UIStackView
------------ UILabel
------------ UILabel
So basically, I have a UITableViewCell, containing an UICollectionView and an UIView, with the following constraints defined in Interface Builder:
UICollectionView.leading = Superview.leading
UICollectionView.trailing = Superview.trailing
UICollectionView.top = Superview.top
UICollectionView.bottom = UIView.top
UIView.leading = Superview.leading
UIView.trailing = Superview.trailing
UIView.bottom = Superview.bottom
The UICollectionView is also set up with a horizontal flow layout.
In my ViewController, I have also overridden the heightForRowAtIndexPath datasource function for the UITableView.
The result is a vertically scrolling list of UITableViewCells, and each UITableViewCell will have a horizontally scrolling list of UIImageViews. The UIView and its two UILabels will display relevant information to the UIImageView when it is focused.
What I am trying to achieve is to hide the UIView containing the two UILabels when the focus moves to a different UITableViewCell. I am able to trap and detect the change in focus by overriding the didUpdateFocusInContext function. I am able to reduce the height of the previously-focused UITableViewCell in the UICollectionViewDelegate, however, the gap between the previously-focused and currently-focused UITableViewCells remain unchanged.
Attempts to set the UITableView.RowHeight to UITableViewAutomaticDimension, setting UITableView.EstimatedRowHeight to an arbitrary figure, removing the overridden heightForRowAtIndexPath function, causes the UICollectionViews to not load at all.
Does anyone have a good suggestion on what I could try?
Edit: Sample source code
ViewController
// ==== ViewController.swift ====
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var tableView: UITableView!
let cellIdentifier = "\(CVTableViewCell.self)"
override func viewDidLoad() {
super.viewDidLoad()
setupControls()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
setupControls()
}
func setupControls() {
setupTableView()
}
func setupTableView() {
tableView.dataSource = self
tableView.delegate = self
// causes collectionView in CVTableViewCell to not load
// tableView.rowHeight = UITableViewAutomaticDimension
// tableView.estimatedRowHeight = 200
tableView.register(UINib(nibName: cellIdentifier, bundle: nil),
forCellReuseIdentifier: cellIdentifier)
}
}
extension ViewController: UITableViewDataSource {
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 5
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 316.0 + 106.0 // 316.0 for image height, 106.0 for labelContainerView
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
guard let dequeuedCell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier, for: indexPath) as? CVTableViewCell else {
fatalError("Unable to dequeue cell")
}
return dequeuedCell
}
}
extension ViewController: UITableViewDelegate {
func tableView(_ tableView: UITableView, canFocusRowAt indexPath: IndexPath) -> Bool {
return false
}
}
CVTableViewCell
// ==== CVTableViewCell.swift ====
import Foundation
import UIKit
class CVTableViewCell: UITableViewCell {
#IBOutlet weak var collectionView: UICollectionView!
#IBOutlet weak var labelContainerView: UIView!
#IBOutlet weak var labelContainerStackView: UIStackView!
#IBOutlet weak var firstLabel: UILabel!
#IBOutlet weak var secondLabel: UILabel!
let cellIdentifier = "\(CVCollectionViewCell.self)"
override func awakeFromNib() {
super.awakeFromNib()
setupControls()
}
override func prepareForReuse() {
super.prepareForReuse()
setupControls()
}
func setupControls() {
setupTableViewCell()
setupCollectionView()
setupLabelContainerView()
setupLabelContainerStackView()
setupLabels()
}
func setupTableViewCell() {
contentView.backgroundColor = .clear
}
func setupCollectionView() {
let layout = UICollectionViewFlowLayout()
layout.scrollDirection = .horizontal
layout.itemSize = CGSize(width: 316.0, height: 316.0)
layout.minimumInteritemSpacing = 0.0
layout.minimumLineSpacing = 50.0
collectionView.dataSource = self
collectionView.delegate = self
collectionView.backgroundColor = .clear
collectionView.clipsToBounds = false
collectionView.collectionViewLayout = layout
collectionView.register(UINib(nibName: cellIdentifier, bundle: nil),
forCellWithReuseIdentifier: cellIdentifier)
}
func setupLabelContainerView() {
labelContainerView.backgroundColor = .clear
}
func setupLabelContainerStackView() {
labelContainerStackView.backgroundColor = .clear
labelContainerStackView.distribution = .fillEqually
}
func setupLabels() {
firstLabel.text = "Look at me"
secondLabel.text = "I refuse to go away"
}
}
extension CVTableViewCell: UICollectionViewDataSource {
func numberOfSections(in collectionView: UICollectionView) -> Int {
return 1
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 5
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
guard let dequeuedCell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdentifier, for: indexPath) as? CVCollectionViewCell else {
fatalError("Unable to dequeue cell")
}
dequeuedCell.imageView.adjustsImageWhenAncestorFocused = true
dequeuedCell.imageView.image = #imageLiteral(resourceName: "stackoverflow")
return dequeuedCell
}
}
extension CVTableViewCell: UICollectionViewDelegate {
override func didUpdateFocus(in context: UIFocusUpdateContext, with coordinator: UIFocusAnimationCoordinator) {
super.didUpdateFocus(in: context, with: coordinator)
// if next focused view is within current collectionview, show labelContainerView
// else hide
if let cell = context.nextFocusedView as? CVCollectionViewCell,
let _ = collectionView.indexPath(for: cell) {
labelContainerView.isHidden = false
} else {
labelContainerView.isHidden = true
}
}
}
CVCollectionViewCell
// ==== CVCollectionViewCell.swift ====
import Foundation
import UIKit
class CVCollectionViewCell: UICollectionViewCell {
#IBOutlet weak var imageView: UIImageView!
override func awakeFromNib() {
super.awakeFromNib()
setupControls()
}
override func prepareForReuse() {
super.prepareForReuse()
setupControls()
}
func setupControls() {
setupImageView()
}
func setupCollectionViewCell() {
backgroundColor = .clear
}
func setupImageView() {
imageView.image = nil
}
}