Load Data in Array

Question

i want to load data in array when i go in the view controller.When i print the array, it is empty but if i use a refresh and print again the array, he is loaded.It is the code :

var information = [String]()

override func viewDidLoad() {
    super.viewDidLoad()
    loadinformation()
    print(information)
}

func loadinformation() {
    let ref = Database.database().reference()
    let uid = Auth.auth().currentUser?.uid
    let prof = ref.child("users").child(uid!).child("interess")
    prof.observeSingleEvent(of: .value,with: { (snapshot) in
        if let dict = snapshot.value as? [String: Any] {
            let name = dict["FullName"] as! String
            self.information.append(name)
        }
    })


}

Shehata Gamal · Accepted Answer · 2018-08-13 23:05:03Z

1

This line

prof.observeSingleEvent(of: .value,with: { (snapshot) in

is asynchronous which means it's doesn't run as the serial flow of code , you need to print it here

let name = dict["FullName"] as! String
self.information.append(name)
print(self.information)

//

Or use completion

func loadinformation(completion:@escaping(_ arr:[String]?) -> Void ) {
    var arr = [String]()
    let ref = Database.database().reference()
    let uid = Auth.auth().currentUser?.uid
    let prof = ref.child("users").child(uid!).child("interess")
    prof.observeSingleEvent(of: .value,with: { (snapshot) in
        if let dict = snapshot.value as? [String: Any] {
            let name = dict["FullName"] as! String
            arr.append(name)
            completion(arr)
        }
        else {
            completion(nil)
        }
    })

}

Call

loadinformation { (result) in
  print(result)
  if let content = result {
    self.information = content 
    self.collectionView.reloadData()
  }
}

edited Aug 13, 2018 at 23:05

answered Aug 13, 2018 at 22:56

Shehata Gamal

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9 Comments

asd a12 Over a year ago

i have a collection view where in every cell i have a label where the text is the value of array[indexpath.row]

asd a12 Over a year ago

i hide the other code because my problem is the array

Shehata Gamal Over a year ago

reload the collection inside the callback

asd a12 Over a year ago

unnder self.information.append... i write collectionview.reloadData()

Shehata Gamal Over a year ago

try the edit it should refresh the collection , your old reload ran before the result returns

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