Trying to append firebase string values to collection view - arrays

Question

I am attempting to add Firebase string values to a collection view but it is giving me an error on the cell.statsLabel.text = statData[indexPath.row] -> Thread 1: EXC_BREAKPOINT (code=1, subcode=0x101ed3b50). My Firebase is correct (I've added values to a label) the problem is appending. It doesn't even go through the retrieveUserData function! The image link below is what my collection view should look like with the left labels being the statHeader array and the right labels being the statData array -> The collectionview image. Any Ideas?
class SceneTwoViewController: UIViewController, GADRewardBasedVideoAdDelegate, UIAlertViewDelegate, UICollectionViewDelegate, UICollectionViewDataSource {
var statHeaders:[String] = []
var statData:[String] = []
var ref: FIRDatabaseReference?
var databaseHandle: FIRDatabaseHandle?
var streakCheck = ""
#IBOutlet var statsCollectionView: UICollectionView!
#IBOutlet var entireView: UIView!
#IBOutlet var activityIndicator: UIActivityIndicatorView!
#IBOutlet var ovImage: UIImageView!
#IBOutlet var Watchbtn: UIButton!
#IBOutlet var StreakImage: UIImageView!
#IBOutlet var StatusLabel: UILabel!
#IBOutlet var TimeDisplay: UIImageView!
#IBOutlet var statusCheck: UILabel!
#IBOutlet var nameLabel: UILabel!
func retrieveUserData() {
let user = FIRAuth.auth()?.currentUser?.uid
ref?.child("users").child(user!).observeSingleEvent(of: .value, with: { snapshot in
print("Dan2")
let value = snapshot.value as? NSDictionary
let statret = value?["status"] as? String ?? ""
let streakret = value?["streakNumber"] as? String ?? ""
let placesret = value?["placesHelped"] as? String ?? ""
self.statData.append(statret)
self.statData.append(streakret)
self.statData.append(placesret)
})
}
override func viewDidLoad() {
super.viewDidLoad()
self.ref = FIRDatabase.database().reference()
let user = FIRAuth.auth()?.currentUser?.uid
print("WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW")
retrieveUserData()
statHeaders.append("Status: ")
statHeaders.append("Streak: ")
statHeaders.append("Places Helped: ")
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return statHeaders.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "statsCell", for: indexPath) as! statsCollectionViewCell //statsCollectionViewCell is name of external file with labels
print(statData.count) // prints 0
print(statHeaders.count) // prints 3
cell.headerLabel.text = statHeaders[indexPath.row]
cell.statsLabel.text = statData[indexPath.row]
return cell
}
}

Answer 1

You are using statHeaders array as a data source for your collection and in the method cellForItemAt you are trying to retrieve objects from that array and from the statData at the same indexPath while your statData is empty. That's why it cause that error.
If your collection mostly depends on statData not on statHeaders, then you should use statData as a datasource.
Also, in your case is very important to check that both arrays have same count of objects, or use optionals like if statHeaders is the main array and the collection should depend on its values, but the statDate is not important, then don't use statData if it doesn't has an object at current indexPath:
if statData.count > indexPath.row {
//use statData array only in this case
}
Also, I don't see that you are trying to reload your collection after retrieving the data.
I think that you should add that reload if your data retrieving works asynchronously:
ref?.child("users").child(user!).observeSingleEvent(of: .value, with: { snapshot in
print("Dan2")
let value = snapshot.value as? NSDictionary
let statret = value?["status"] as? String ?? ""
let streakret = value?["streakNumber"] as? String ?? ""
let placesret = value?["placesHelped"] as? String ?? ""
self.statData.append(statret)
self.statData.append(streakret)
self.statData.append(placesret)
self.statsCollectionView.reloadData()
})