Swift Firebase UIRefreshControl creates duplicate posts - ios

Question

When I am using the UIRefreshControl on this view controller for my tableview array it just adds two duplicate posts making it 3 of the same posts instead of just showing the 1 that was already there. I have a UIRefreshController on different view controllers and they work fine, but I think it has to do with my firebase call since I am checking to see the loggedInUser and who they are following and adding those posts to a array. Not sure how to switch my call to where it just refreshes instead of duplicating. Thanks.
override func viewDidLoad() {
super.viewDidLoad()
databaseRef = Database.database().reference()
locationManager.delegate = self
locationManager.distanceFilter = kCLLocationAccuracyNearestTenMeters
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.startUpdatingLocation()
locationManager.stopUpdatingLocation()
// refresh control
let refreshControl = UIRefreshControl()
refreshControl.addTarget(self, action: #selector(refreshControlAction(refreshControl:)), for: UIControlEvents.valueChanged)
self.feedTableView.insertSubview(refreshControl, at: 0)
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
if CLLocationManager.locationServicesEnabled() {
switch(CLLocationManager.authorizationStatus()) {
case .notDetermined, .restricted, .denied:
print("No access")
fetchPosts(refreshing: false, refreshControl: nil)
//getAllPostsWithoutLocation(refreshing: false, refreshControl: nil)
case .authorizedAlways, .authorizedWhenInUse:
print("Access")
fetchPostsWithLocation(refreshing: false, refreshControl: nil)
//getAllPosts(refreshing: false, refreshControl: nil)
}
} else {
print("Location services are not enabled")
}
}
#objc func refreshControlAction(refreshControl: UIRefreshControl) {
if CLLocationManager.locationServicesEnabled() {
switch(CLLocationManager.authorizationStatus()) {
case .notDetermined, .restricted, .denied:
print("No access")
fetchPosts(refreshing: true, refreshControl: refreshControl)
//getAllPostsWithoutLocation(refreshing: true, refreshControl: refreshControl)
case .authorizedAlways, .authorizedWhenInUse:
print("Access")
fetchPostsWithLocation(refreshing: true, refreshControl: refreshControl)
//getAllPosts(refreshing: true, refreshControl: refreshControl)
}
} else {
print("Location services are not enabled")
}
}
func fetchPostsWithLocation(refreshing: Bool, refreshControl: UIRefreshControl?) {
Database.database().reference().child("user_profiles").child((loggedInUser?.uid)!).child("following").observe(.value, with: { snapshot in
if snapshot.exists() {
MBProgressHUD.showAdded(to: self.view, animated: true)
let databaseRef = Database.database().reference()
// retrieves all users from database
databaseRef.child("user_profiles").queryOrderedByKey().observeSingleEvent(of: .value, with: { (usersSnapshot) in
let users = usersSnapshot.value as! [String: AnyObject]
// retrieve user's following list and append it
for (_, value) in users {
print(value)
if let userID = value["uid"] as? String {
if userID == Auth.auth().currentUser?.uid {
print(value)
if let followingUsers = value["following"] as? [String : String] {
for (_,user) in followingUsers {
self.following.append(user)
}
}
// append user's id to see own posts
//self.following.append(Auth.auth().currentUser!.uid)
// retrieve all posts from the database
databaseRef.child("posts").queryOrderedByKey().observeSingleEvent(of: .value, with: { (postsSnapshot) in
let posts = postsSnapshot.value as! [String: AnyObject]
// retrieve posts of each follower and user
for (_, post) in posts {
for (_, postInfo) in post as! [String: AnyObject] {
if let followingID = postInfo["uid"] as? String {
for each in self.following {
if each == followingID {
guard let uid = postInfo["uid"] as! String! else {return}
guard let caption = postInfo["caption"] as! String! else {return}
guard let downloadURL = postInfo["download_url"] as! String! else {return}
guard let name = postInfo["businessName"] as! String! else {return}
guard let timestamp = postInfo["timestamp"] as! Double! else {return}
let date = Date(timeIntervalSince1970: timestamp/1000)
guard let address = postInfo["businessStreet"] as! String! else {return}
guard let state = postInfo["businessCity"] as! String! else {return}
guard let postID = postInfo["postID"] as! String! else {return}
let lat = Double(postInfo["businessLatitude"] as! String)
let long = Double(postInfo["businessLongitude"] as! String)
let businessLocation = CLLocation(latitude: lat!, longitude: long!)
let latitude = self.locationManager.location?.coordinate.latitude
let longitude = self.locationManager.location?.coordinate.longitude
let userLocation = CLLocation(latitude: latitude!, longitude: longitude!)
let distanceInMeters: Double = userLocation.distance(from: businessLocation)
let distanceInMiles: Double = distanceInMeters * 0.00062137
let distanceLabelText = String(format: "%.2f miles away", distanceInMiles)
let post = Post(uid: uid, caption: caption, downloadURL: downloadURL, name: name, date: date, address: address, state: state, distance: distanceLabelText, postID: postID)
self.feeds.append(post)
self.tableView.reloadData()
self.refreshControl?.endRefreshing()
}
self.feeds.sort {$0.date.compare($1.date) == .orderedDescending}
//self.feeds.sort {$0.distance.compare($1.distance) == .orderedAscending}
self.tableView.reloadData()
}
}
}
}
MBProgressHUD.hide(for: self.view, animated: true)
}) { (error) in
print(error.localizedDescription)
}
}
}
}
})
} else {
print("Not following anyone")
}
})
}

Answer 1

When your api call from firebase returns, you’re just appending the result in your array without removing old content.
Do this in your fetchPostsWithLocation method where you add your results to your array:
self.following.removeAll()
self.following.append(user)
self.feeds.removeAll()
self.feeds.append(post)
And then reload your table view.