Strange behavior in table view after deleting event - ios

Question

I am working on an app which has users register for volunteering events, and am currently working on letting them view their own events and unregister.
This is the screen the users sees when the ask to view their events, in this case the two events are called "ok" and "that" (I just created some random testing events). When you click on one this is the screen you get:
When you click unregister, the event is deleted from your registeredEvents, but the table view now has two of the same events.
When I click back, and then go back to the table view, everything is normal, in this case only displaying the "ok" event, because the other one was deleted. Here is the code for the tableview layout:
override func viewDidLoad() {
super.viewDidLoad()
yourArray = []
actualEvents = []
let id = Auth.auth().currentUser?.uid
Database.database().reference().child("users").child(id!).child("registeredEvents").observe(.value) { snapshot in
let children = snapshot.children
while let rest = children.nextObject() as? DataSnapshot, let value = rest.value {
print(value)
self.yourArray.append(value as! String)
}
Database.database().reference().child("Events").observe(.value) { (data) in
let events = data.value as! [String:[String:Any]]
for(_,value) in events{
if(self.yourArray.contains(value["EventName"]! as! String)){
self.actualEvents.append(PersonalEvents(evName: value["EventName"]! as! String, evDesc: value["EventDescription"]! as! String, evStartDate: value["start time"]! as! String, evEndDate: value["end time"] as! String, evNumPeople: value["NumberOfPeople"]! as! Int, evNumRegistered: value["currentPeople"] as! Int))
}
}
print("Actual events array " + "\(self.actualEvents)")
}
self.tblEvents.reloadData()
}
print(yourArray)
self.tblEvents.dataSource = self
self.tblEvents.delegate = self
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return yourArray.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "productstable", for: indexPath)
cell.textLabel?.text = self.yourArray[indexPath.row]
return cell
}
And the unregister button(This is in a different view controller, becuase info is displayed about the events in a different view):
#IBAction func didUnregister(_ sender: Any) {
let id = Auth.auth().currentUser?.uid
let ref = Database.database().reference()
ref.child("users").child(id!).child("registeredEvents").child(personalEventInfo!.eventName!).removeValue { error,arg in
if error != nil {
print("error \(error)")
}
}
let event = ref.child("Events")
event.child(personalEventInfo!.eventName!).observeSingleEvent(of: .value) { (snapshot) in
let value = snapshot.value as! NSDictionary
var currentPeople = value["currentPeople"] as! Int
currentPeople = currentPeople - 1
Database.database().reference().child("Events").child(self.personalEventInfo!.eventName!).child("currentPeople").setValue(currentPeople)
}
}
Please let me know if this is confusing, but if it is not, then please let me know why this is happening, and what I can do to fix it.

Answer 1

Remove the items inside the Array before you append the data inside.
Improvement: You need to take care your memory by using [weak self] inside these closures.
Can you try the following:
Database.database().reference().child("users").child(id!).child("registeredEvents").observe(.value) { [weak self] snapshot in
let children = snapshot.children
self?.yourArray.removeAll()
while let rest = children.nextObject() as? DataSnapshot, let value = rest.value {
print(value)
self?.yourArray.append(value as! String)
}
Database.database().reference().child("Events").observe(.value) { [weak self] (data) in
let events = data.value as! [String:[String:Any]]
self?.actualEvents.removeAll()
for(_,value) in events{
if(self?.yourArray.contains(value["EventName"]! as! String)){
self?.actualEvents.append(PersonalEvents(evName: value["EventName"]! as! String, evDesc: value["EventDescription"]! as! String, evStartDate: value["start time"]! as! String, evEndDate: value["end time"] as! String, evNumPeople: value["NumberOfPeople"]! as! Int, evNumRegistered: value["currentPeople"] as! Int))
}
}
print("Actual events array " + "\(self?.actualEvents)")
}
self?.tblEvents.reloadData()
}