UIRefreshControl endRefresh jumps when used with Large Title enabled - ios

Question

I'm trying to use UIRefreshControl, but when I call endRefreshing() it jumps the UINavigationBar. The problem only happens when I use UIRefreshControl along with large titles.
Looking at some similar issues (UIRefreshControl glitching in combination with custom TableViewCell) reported here, I tried to refresh only after dragging ends, nevertheless, the bug still occurs. Also tried to use
self.navigationController?.navigationBar.isTranslucent = false and self.extendedLayoutIncludesOpaqueBars = true
But, none of the solutions found on other questions seems to resolve the problem, it still not smooth.
The video of what is happening:
https://www.youtube.com/watch?v=2BBRnZ444bE
The app delegate
import UIKit
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(
_ application: UIApplication,
didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
) -> Bool {
let window = UIWindow(frame: UIScreen.main.bounds)
window.makeKeyAndVisible()
let nav = UINavigationController()
nav.title = "My Nav"
nav.navigationBar.prefersLargeTitles = true
nav.viewControllers = [ViewController()]
window.rootViewController = nav
self.window = window
return true
}
}
Observe that I'm using large titles:
let nav = UINavigationController()
nav.title = "My Nav"
nav.navigationBar.prefersLargeTitles = true
The ViewController:
import UIKit
import Foundation
final class ViewController: UICollectionViewController {
let randomHeight = Int.random(in: 100..<300)
init() {
let layout = UICollectionViewFlowLayout()
layout.scrollDirection = .vertical
layout.estimatedItemSize = CGSize(width: 20, height: 20)
super.init(collectionViewLayout: layout)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func viewDidLoad() {
super.viewDidLoad()
navigationItem.title = "Try to refresh"
self.navigationController?.navigationBar.isTranslucent = false
self.extendedLayoutIncludesOpaqueBars = true
collectionView.backgroundColor = .white
registerCells()
setupRefreshControl()
}
private func registerCells() {
self.collectionView.register(
Cell.self,
forCellWithReuseIdentifier: "Cell"
)
}
private func setupRefreshControl() {
let refreshControl = UIRefreshControl()
refreshControl.addTarget(
self,
action: #selector(refreshControlDidFire),
for: .valueChanged
)
self.collectionView.refreshControl = refreshControl
}
#objc private func refreshControlDidFire(_ sender: Any?) {
if let sender = sender as? UIRefreshControl, sender.isRefreshing {
refresh()
}
}
override func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
if collectionView.refreshControl!.isRefreshing {
refresh()
}
}
private func refresh() {
if !collectionView.isDragging {
collectionView.refreshControl!.endRefreshing()
collectionView.perform(#selector(collectionView.reloadData), with: nil, afterDelay: 0.05)
}
}
}
extension ViewController {
override func numberOfSections(in collectionView: UICollectionView) -> Int {
return 1
}
override func collectionView(
_ collectionView: UICollectionView,
numberOfItemsInSection section: Int
) -> Int {
return 10
}
override func collectionView(_ collectionView: UICollectionView,
cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
guard let cell = collectionView.dequeueReusableCell(
withReuseIdentifier: "Cell", for: indexPath
) as? Cell else {
return UICollectionViewCell()
}
cell.label.text = "Text number \(indexPath.row), with height \(randomHeight)"
cell.heightAnchorConstraint.constant = CGFloat(randomHeight)
return cell
}
}
extension ViewController: UICollectionViewDelegateFlowLayout {
func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
insetForSectionAt section: Int) -> UIEdgeInsets {
return UIEdgeInsets(top: 20, left: 0, bottom: 0, right: 0)
}
}
final class Cell: UICollectionViewCell {
private let shadowView = UIView()
private let containerView = UIView()
private let content = UIView()
let label = UILabel()
var heightAnchorConstraint: NSLayoutConstraint!
override init(frame: CGRect = .zero) {
super.init(frame: frame)
setupViews()
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
private func setupViews() {
insertSubview(shadowView, at: 0)
addSubview(containerView)
containerView.addSubview(label)
containerView.addSubview(content)
activateConstraints()
}
private func activateConstraints() {
self.translatesAutoresizingMaskIntoConstraints = false
shadowView.translatesAutoresizingMaskIntoConstraints = false
containerView.translatesAutoresizingMaskIntoConstraints = false
label.translatesAutoresizingMaskIntoConstraints = false
content.translatesAutoresizingMaskIntoConstraints = false
shadowView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
shadowView.leadingAnchor.constraint(equalTo: self.leadingAnchor).isActive = true
shadowView.trailingAnchor.constraint(equalTo: self.trailingAnchor).isActive = true
shadowView.bottomAnchor
.constraint(equalTo: self.bottomAnchor).isActive = true
containerView.backgroundColor = .white
containerView.layer.cornerRadius = 14
containerView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
containerView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
containerView.leadingAnchor.constraint(equalTo: self.leadingAnchor).isActive = true
containerView.trailingAnchor.constraint(equalTo: self.trailingAnchor).isActive = true
let widthAnchorConstraint = containerView.widthAnchor.constraint(equalToConstant: UIScreen.main.bounds.width - 20)
widthAnchorConstraint.identifier = "Width ContainerView"
widthAnchorConstraint.priority = .defaultHigh
widthAnchorConstraint.isActive = true
label.numberOfLines = 0
label.textAlignment = .center
label.centerXAnchor.constraint(equalTo: containerView.centerXAnchor).isActive = true
label.centerYAnchor.constraint(equalTo: containerView.centerYAnchor).isActive = true
label.leadingAnchor.constraint(equalTo: containerView.leadingAnchor).isActive = true
label.trailingAnchor.constraint(equalTo: containerView.trailingAnchor).isActive = true
content.leadingAnchor.constraint(equalTo: containerView.leadingAnchor, constant: 20).isActive = true
content.topAnchor.constraint(equalTo: containerView.topAnchor, constant: 10).isActive = true
content.bottomAnchor.constraint(lessThanOrEqualTo: containerView.bottomAnchor, constant: -10).isActive = true
heightAnchorConstraint = content.heightAnchor.constraint(greaterThanOrEqualToConstant: 220)
heightAnchorConstraint.identifier = "Height Content"
heightAnchorConstraint.priority = .defaultHigh
heightAnchorConstraint.isActive = true
content.widthAnchor.constraint(equalToConstant: 40).isActive = true
content.backgroundColor = .red
}
override func layoutSubviews() {
super.layoutSubviews()
applyShadow(width: 0.20, height: -0.064)
}
private func applyShadow(width: CGFloat, height: CGFloat) {
let shadowPath = UIBezierPath(roundedRect: shadowView.bounds, cornerRadius: 14.0)
shadowView.layer.masksToBounds = false
shadowView.layer.shadowRadius = 8.0
shadowView.layer.shadowColor = UIColor.black.cgColor
shadowView.layer.shadowOffset = CGSize(width: width, height: height)
shadowView.layer.shadowOpacity = 0.3
shadowView.layer.shadowPath = shadowPath.cgPath
}
}

Answer 1

The problem is related to layout.estimatedItemSize = CGSize(width: 20, height: 20)
When we use AutoLayout to resize the cell, it creates a bug with UIRefreshControl and navigation bar large title. So, if you use layout.estimatedItemSize with an equal or greater size than we expected. So the bug will not happen and the glitch will not happen.
Basically, the problem is when we call updateData but the cell is bigger than we expect and each cell of the UICollectinView will resize to a bigger size then the UICollectionViewController will glitches.

Answer 2

So, I try your code and all works fine.
But I ran it on iPhone 7 - no large title there.
I think, it is largeTitle issue.
You can try use this code snippet:
self.navigationController?.navigationBar.prefersLargeTitles = false
self.navigationController?.navigationBar.prefersLargeTitles = true