How do I hide the activity indicator once there is no more data to load? - swift

Question

I am paginating data from Firestore and I am able to get that to work.
Here is the paginating query:
if restaurantArray.isEmpty {
query = db.collection("Restaurant_Data").limit(to: 4)
} else {
query = db.collection("Restaurant_Data").start(afterDocument: lastDocument!).limit(to: 4)
}
query.getDocuments { (querySnapshot, err) in
if let err = err {
print("\(err.localizedDescription)")
} else if querySnapshot!.isEmpty {
self.fetchMore = false
return
} else {
if (querySnapshot!.isEmpty == false) {
let allQueriedRestaurants = querySnapshot!.documents.compactMap { (document) -> Restaurant in (Restaurant(dictionary: document.data(), id: document.documentID)!)}
guard let location = self.currentLocation else { return }
self.restaurantArray.append(contentsOf: self.applicableRestaurants(allQueriedRestaurants: allQueriedRestaurants, location: location))
DispatchQueue.main.asyncAfter(deadline: .now() + 1, execute: {
self.tableView.reloadData()
self.fetchMore = false
})
self.lastDocument = querySnapshot!.documents.last
}
}
}
The pagination is triggered when the user drags the table view up:
override func scrollViewDidScroll(_ scrollView: UIScrollView) {
let off = scrollView.contentOffset.y
let off1 = scrollView.contentSize.height
if off > off1 - scrollView.frame.height * leadingScreensForBatching{
if !fetchMore { // excluded reachedEnd Bool
if let location = self.currentLocation {
queryGenerator(searched: searchController.isActive, queryString: searchController.searchBar.text!.lowercased(), location: location)
}
}
}
}
I also added an activity indicator to the bottom and that works as expected. Here is the code for that:
override func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
let lastSectionIndex = tableView.numberOfSections - 1
let lastRowIndex = tableView.numberOfRows(inSection: lastSectionIndex) - 1
if indexPath.section == lastSectionIndex && indexPath.row == lastRowIndex {
// print("this is the last cell")
let spinner = UIActivityIndicatorView(style: .medium)
spinner.startAnimating()
spinner.frame = CGRect(x: CGFloat(0), y: CGFloat(0), width: tableView.bounds.width, height: CGFloat(44))
tableView.tableFooterView = spinner
tableView.tableFooterView?.isHidden = false
}
}
However, once the bottom of the table view is reached and there is no more data available, the indicator is still showing and I dont know how to get it to not show.
I tried using a variable to check if the Firestory query is done but my implementation is probably wrong so I cannot get it to work.

Answer 1

If you know the moment when there is no more data available, you set the tableView footer view to nil or hidden = true, see below
tableView.tableFooterView?.isHidden = true
or
tableView.tableFooterView = nil
before you call self.tableView.reloadData()
If you do not know it, see code below
query.getDocuments { (querySnapshot, err) in
if let err = err {
print("\(err.localizedDescription)")
} else if querySnapshot!.isEmpty {
// Here you know when there is no more data
self.fetchMore = false
self.tableView.tableFooterView = nil // or self.tableView.tableFooterView?.isHidden = true
self.tableView.reloadData()
return
} else {
if (querySnapshot!.isEmpty == false) {
let allQueriedRestaurants = querySnapshot!.documents.compactMap { (document) -> Restaurant in (Restaurant(dictionary: document.data(), id: document.documentID)!)}
guard let location = self.currentLocation else { return }
self.restaurantArray.append(contentsOf: self.applicableRestaurants(allQueriedRestaurants: allQueriedRestaurants, location: location))
DispatchQueue.main.asyncAfter(deadline: .now() + 1, execute: {
self.tableView.reloadData()
self.fetchMore = false
})
self.lastDocument = querySnapshot!.documents.last
}
}
}