Disable users to scroll up in tableView? - swift

Question

Similar to tinder, if a user goes down, I don't want them to be able to go back upwards. How do I do this?
I tried the code below, but it keeps running an error: Index out of range.
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return userList.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "tableCell", for: indexPath) as! FeedTableViewCell
cell.collectionView.delegate = self
cell.collectionView.dataSource = self
//reloading the tableview
let artist: UserModel
artist = self.userList[indexPath.row]
cell.nameLabel.text = artist.name
cell.passionLabel.text = artist.passion
cell.collectionView.reloadData()
if indexPath.row == 1 {
userList.removeFirst()
}
return cell
}

Answer 1

Refer below code,
You need to store last scroll Content Offset of tableview, when user scroll down, refer scrollViewDidScroll method.
#IBOutlet weak var tableView: UITableView!
var lastContentOffsetY:CGFloat = 0.0
override func viewDidLoad() {
super.viewDidLoad()
self.tableView.bounces = false
self.tableView.register(UITableViewCell.self, forCellReuseIdentifier: "reuse")
self.tableView.reloadData()
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 50
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "reuse")
return cell!
}
func scrollViewDidScroll(_ scrollView: UIScrollView) {
if(scrollView.contentOffset.y < self.lastContentOffsetY){
self.tableView.setContentOffset(CGPoint(x:scrollView.contentOffset.x, y: self.lastContentOffsetY), animated: false)
}else{
self.lastContentOffsetY = scrollView.contentOffset.y
}
}