Converting DataSnapshot to custom struct object - Swift 4 - firebase

Question

So, In my project I've created a custom struct:
import Foundation
import Firebase
struct CheckedIn {
let ref: DatabaseReference?
let key: String
let max_cm: String
let max_in: String
let weight_kg: Int
let weight_lb: Int
init(key: String = "", max_cm: String, max_in: String, weight_kg: Int, weight_lb: Int) {
self.ref = nil
self.key = key
self.max_cm = max_cm
self.max_in = max_in
self.weight_kg = weight_kg
self.weight_lb = weight_lb
}
init?(snapshot: DataSnapshot) {
guard
let value = snapshot.value as? [String: AnyObject],
let max_cm = value["checked_max_cm"] as? String,
let max_in = value["checked_max_in"] as? String,
let weight_kg = value["checked_weight_kg"] as? Int,
let weight_lb = value["checked_weight_in"] as? Int
else {
return nil
}
self.ref = snapshot.ref as DatabaseReference
self.key = snapshot.key
self.max_cm = max_cm
self.max_in = max_in
self.weight_kg = weight_kg
self.weight_lb = weight_lb
}
func toAnyObject() -> Any {
return [
"checked_max_cm": self.max_cm,
"checked_max_in": self.max_in,
"checked_weight_kg": self.weight_kg,
"checked_weight_in": self.weight_lb
]
}
}
This is the structure of my database:
And I'm trying to retrieve some data in a view controller using the following code:
ref.queryOrderedByKey().observe(.value) { (snapshot) in
var newItems: [CheckedIn] = []
for child in snapshot.children {
print(child)
if let snapshot = child as? DataSnapshot, let company = CheckedIn(snapshot: snapshot) {
newItems.append(company)
}
}
print(newItems)
self.companiesCheckedIn = newItems
self.tableView.reloadData()
UIViewController.removeSpinner(spinner: sv)
}
The problem is that, whenever I try to open the view controller (this chunk of code is inside the .viewDidLoad), the list 'newItems' is empty. The strange thing is that when I try to run
print(child)
all of the data is printed,
So I assume that the 'if let snapshot = child as? DataSnapshot, let company = CarryOn(snapshot: snapshot)' block is not running, what should I do?

Answer 1

Managed to solve the problem using a workaround:
This code goes before the viewDidLoad() method of your ViewController
let ref = Database.database().reference().child("alldata")
var companyName: [String] = []
var maxCm: [String] = []
var maxIn: [String] = []
var weightKg: [Int] = []
var weightLb: [Int] = []
And in the viewDidLoad()
override func viewDidLoad() {
super.viewDidLoad()
ref.queryOrderedByKey().observeSingleEvent(of: .value) { (snapshot) in
let snapshotValue = snapshot.value as! [String:[String:AnyObject]]
let sorted = snapshotValue.sorted() { $0.key.lowercased() < $1.key.lowercased() }
for (key, _) in sorted {
let keys = snapshotValue[key]
let company_name = key
self.companyName.append(company_name)
let carry_max_cm = keys?["keyname"] as! String
self.maxCm.append(carry_max_cm)
let carry_max_in = keys?["keyname"] as! String
self.maxIn.append(carry_max_in)
let carry_weight_kg = keys?["keyname"] as! Int
self.weightKg.append(carry_weight_kg)
let carry_weight_lb = keys?["keyname"] as! Int
self.weightLb.append(carry_weight_lb)
}
self.tableView.reloadData()
}
}
let sorted = snapshotValue.sorted() { $0.key.lowercased() < $1.key.lowercased() }
Orders the dictionary alphabetically

Answer 2

your "checked_weight_kg" & "checked_weight_in" is a integer type but you assign String type.
your code ->
let weight_kg = value["checked_weight_kg"] as? String,
let weight_lb = value["checked_weight_in"] as? String
to Change ->
init?(snapshot: DataSnapshot) {
guard
let value = snapshot.value as? [String: AnyObject],
let max_cm = value["carry_max_cm"] as? String,
let max_in = value["carry_max_in"] as? String,
let weight_kg = value["checked_weight_kg"] as? Int,
let weight_lb = value["checked_weight_in"] as? Int
else {
return nil
}
self.ref = snapshot.ref as DatabaseReference
self.key = snapshot.key
self.max_cm = max_cm
self.max_in = max_in
self.weight_kg = weight_kg
self.weight_lb = weight_lb
}