Swift - Save all documents of firestore collection in a list of objects - swift

Question

I want to retrieve all the documents of a firestore collection, and then write it in an object then append it my list of objects.
after that i display it in an UITableView.
Here is what I have, it works without errors but when I run it, nothing is displayed.
The list structure:
struct RewardsStruct {
//var rewardKey: String
var Reward: String
var noPoints: String
var QRimageURL: ImageURL = ImageURL(url: nil, didLoad: false)
var Desc: String
var isvalid: Bool
}
Here is my retrieving code:
private func getRewards() {
var rewardsList = [RewardsStruct]()
let db = Firestore.firestore()
db.collection("Rewards").getDocuments { (snapshot, error) in
if error != nil {
print(error)
} else {
for document in (snapshot?.documents)! {
let code = RewardsStruct( Reward: document.data()["Reward"] as! String , noPoints: document.data()["noPoints"] as! String , QRimageURL: document.data()["QRimageURL"] as! ImageURL, Desc:document.data()["Desc"] as! String, isvalid: (document.data()["isvalid"] != nil) )
self.rewardsList.append(code)
DispatchQueue.main.async {
self.CodeTable.reloadData()
}
}
}
}
}
The rest of code in ViewController as some requests
class RewardsVC: UIViewController {
var rewardsList = [RewardsStruct]()
var reward:RewardsStruct!
#IBOutlet weak var infoView: UIView!
#IBOutlet weak var ViewLabel: UILabel!
#IBOutlet weak var CodeTable: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
CodeTable.delegate = self
CodeTable.dataSource = self
ViewLabel.isHidden = true
infoView.makeCornerRounded(cornerRadius: 30, maskedCorners: [.layerMinXMinYCorner, .layerMaxXMinYCorner])
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
rewardsList.removeAll()
getRewards()
}
private func getRewards() {
....
}
extension RewardsVC: UITableViewDelegate, UITableViewDataSource{
func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
CodeTable.backgroundColor = UIColor(named: "#F5F5F5")
return 60
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 125
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
print("List number of rows")
print(rewardsList.count)
return rewardsList.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "RewardsCell") as! RewardsCell
let object = rewardsList[indexPath.row]
cell.Reward.text = object.Reward
cell.Desc.text = object.Desc
cell.noPoints.text = "-" + object.noPoints + " Points"
return cell
}
func addShadow(backgroundColor: UIColor = .white, cornerRadius: CGFloat = 12, shadowRadius: CGFloat = 5, shadowOpacity: Float = 0.1, shadowPathInset: (dx: CGFloat, dy: CGFloat), shadowPathOffset: (dx: CGFloat, dy: CGFloat)) {
} }
Here is my FireStore:

Answer 1

Try this example code, to ...save all documents of firestore collection in a list of objects....
getRewards(...) is called an asynchronous function, and needs a way to "wait" for the results to be available before you can use them.
There are many ways to do this, here I present an example code that uses a completion handler to pass the results (or errors) of getRewards(...) back to the calling function. Note, the code is untested since I do not have your database (or even Firestore).
// -- here some error type for testing
enum FireError: Error {
case decodingError
case badError
// ...
}
// -- here completion handler
private func getRewards(completion: #escaping ([RewardsStruct], FireError?) -> ()) {
var rewardsList = [RewardsStruct]()
let db = Firestore.firestore()
db.collection("Rewards").getDocuments { (snapshot, error) in
if error != nil {
print(error)
completion([], FireError.badError) // <-- here
} else {
for document in (snapshot?.documents)! {
let code = RewardsStruct(Reward: document.data()["Reward"] as! String , noPoints: document.data()["noPoints"] as! String , QRimageURL: document.data()["QRimageURL"] as! ImageURL, Desc:document.data()["Desc"] as! String, isvalid: (document.data()["isvalid"] != nil) )
self.rewardsList.append(code)
}
completion(rewardsList, nil) // <-- here
}
}
}
Use the function like this:
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
getRewards() { results, error in // <-- here
if error == nil {
rewardsList.removeAll()
rewardsList = results
DispatchQueue.main.async {
self.CodeTable.reloadData()
}
} else {
// todo deal with errors
}
}
}
Alternatively, you can also use this code, without using a completion handler, since getRewards(...) is inside your UIViewController.
private func getRewards() {
let db = Firestore.firestore()
db.collection("Rewards").getDocuments { (snapshot, error) in
if error != nil {
print(error)
} else {
self.rewardsList.removeAll() // <-- here
for document in (snapshot?.documents)! {
let code = RewardsStruct(Reward: document.data()["Reward"] as! String , noPoints: document.data()["noPoints"] as! String , QRimageURL: document.data()["QRimageURL"] as! ImageURL, Desc:document.data()["Desc"] as! String, isvalid: (document.data()["isvalid"] != nil) )
self.rewardsList.append(code) // <-- here
}
DispatchQueue.main.async { // <-- here
self.CodeTable.reloadData()
}
}
}
}
and use it like this:
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
getRewards()
}