Refreshing a view controller on Firebase logout - swift

Question

I have a view controller that has a UICollectionView with information pulled from Firebase. When a user visits this view controller their info is placed in the collection view cells.
However, when the user logs out and logs in with a different account, the previous user's data stays in the collection view rather than re-populating with the new user's info.
Right now everything is called from viewDidLoad():
override func viewDidLoad() {
super.viewDidLoad()
loadData()
loadOngoingQuest()
collectionView.dataSource = self
collectionView.delegate = self
}
loadData() and loadOngoingQuest() pull info from Firebase into arrays used to populate the collection view.
I have tried adding everything in viewWillAppear() instead, but it causes some glitches as the collection view involves scrolling and other animations that I don't want to run every time the view controller appears.
Basically I just want to reload the entire view controller every time the user logs out. How can I do this?

Answer 1

You should do something like this, see comments for more info:
let firebaseAuth = FIRAuth.auth()
do {
try firebaseAuth?.signOut()
// clear the array that your collectionView is based on
// reload your collectionView (which will clear all the data since your array is empty)
} catch let signOutError as NSError {
print ("Error signing out: %#", signOutError)
}
Update:
Another way of handling this:
Create a Struct with the following property:
struct Global {
var isNewUser = false
}
Whenever you logout a user do this:
Global.isNewUser = true
And in your collectionView you check if Global.isNewUser == true then reload everything and most important do set Global.isNewUser = false. That way you´ll only load everything once.

Answer 2

After a lot of frustration I figured out the issue!
It was nothing to do with refreshing collection views or view controllers. I was using Firebase refs wrong. I had saved two refs in as global constants in a struct in hopes of not having to declare them on every VC. It was like this:
struct GlobalConstants {
struct Refs {
static let userRef = AppDatabaseReference.users(uid: (Auth.auth().currentUser?.uid)!).reference()
static let currentUser = Auth.auth().currentUser?.uid
}
}
I would then use them anywhere in my code like this:
var questsRef = var questsRef = GlobalConstants.Refs.userRef.reference().child("quests")
This would cause issues unless I terminated the app and opened it again, refreshing these variables.
I went back to declaring let userRef = AppDatabaseReference.users(uid: (Auth.auth().currentUser?.uid)!).reference() at the top in every VC and it solved the issue!