The problem: I cannot get data downloaded into arrays in a singleton class to populate table views in two view controllers.
I am writing a bank book iOS app with a Parse backend. I have a login viewController and four other view controllers in a Tab Bar Controller. I have a singleton class that gets data from the Parse server and loads four arrays. I want that data to populate table views in two other view controllers. I want to make as few data calls as possible. The initial view controller is where user enters debits and credits. So my plan was to call GetData class from the viewDidLoad to populate tables in case user visits them without entering a debit or a credit.
When a debit or credit is entered, there is one function where after the debit or credit is saved to Parse server, the GetData class is called again to update the arrays in the GetData class.
The two view controllers access the arrays in the GetData class to fill the tables, and there is a tableView.reloadData() call in the viewDidAppear in each view controller when the view is accessed via the tab controller.
It works intermittently at best. sometimes I get five successful updates and then it keeps displaying old data, then it will suddenly display all the data.
Looking at my cloud DB, all the entries are there when made, and I have verified the viewWillAppear is firing in each view controller who accessed.
What I need is a reliable method to get the data to update in the other view controllers every. time. I will gladly scrap this app and rewrite if needed.
Here is the code of my singleton class:
class GetData {
static let sharedInstance = GetData()
var transactionArray = [String]()
var dateArray = [String]()
var toFromArray = [String]()
var isDebitArray = [String]()
func getdata() {
let query = PFQuery(className:"Transaction")
query.findObjectsInBackground { (objects, error) in
self.transactionArray.removeAll()
self.dateArray.removeAll()
self.toFromArray.removeAll()
self.isDebitArray.removeAll()
print("query fired")
if objects != nil {
for object in objects! {
if let amount = object.object(forKey: "amount") as? String {
if let date = object.object(forKey: "date") as? String {
if let toFrom = object.object(forKey: "toFrom") as? String {
if let isDebit = object.object(forKey: "isDebit") as? String {
self.transactionArray.append(amount)
self.dateArray.append(date)
self.toFromArray.append(toFrom)
self.isDebitArray.append(isDebit)
}
}
}
}
}
}
self.transactionArray.reverse()
self.dateArray.reverse()
self.toFromArray.reverse()
self.isDebitArray.reverse()
dump(self.toFromArray)
}
}
}
Here is a sample of one of the view controllers:
class RecordVC: UIViewController, UITableViewDelegate, UITableViewDataSource {
@IBOutlet var recordTableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
recordTableView.delegate = self
recordTableView.dataSource = self
recordTableView.reloadData()
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
recordTableView.reloadData()
print("recordVC viewWillAppear fired")
}
@IBAction func resetFoundButton(_ sender: Any) {
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = recordTableView.dequeueReusableCell(withIdentifier: "RecordCell", for: indexPath) as! RecordCell
cell.amountLabel?.text = "$\(GetData.sharedInstance.transactionArray[indexPath.row])"
cell.dateLabel?.text = "\(GetData.sharedInstance.dateArray[indexPath.row])"
cell.toFromLabel?.text = "\(GetData.sharedInstance.toFromArray[indexPath.row])"
let cellColor = backGroundColor(isDebit: GetData.sharedInstance.isDebitArray[indexPath.row])
cell.backgroundColor = cellColor
cell.backgroundColor = cellColor
return cell
}
func backGroundColor(isDebit:String) -> UIColor{
if isDebit == "false" {
return UIColor.green
} else {
return UIColor.blue
}
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return GetData.sharedInstance.transactionArray.count
}
}
Thank you
I would say that instead of reloading the tables by calling tableView.reloadData() in viewWillAppear() , after your query execution and data updates in GetData Class , then you should fire a notification or use a delegate to reloadData() in tableview.
Whats happening is that sometimes when the tableView.reloadData() gets called the Data in the singleton class (GetData class) has not yet updated.
func getdata() {
let query = PFQuery(className:"Transaction")
query.findObjectsInBackground { (objects, error) in
self.transactionArray.removeAll()
self.dateArray.removeAll()
self.toFromArray.removeAll()
self.isDebitArray.removeAll()
print("query fired")
if objects != nil {
for object in objects! {
if let amount = object.object(forKey: "amount") as? String {
if let date = object.object(forKey: "date") as? String {
if let toFrom = object.object(forKey: "toFrom") as? String {
if let isDebit = object.object(forKey: "isDebit") as? String {
self.transactionArray.append(amount)
self.dateArray.append(date)
self.toFromArray.append(toFrom)
self.isDebitArray.append(isDebit)
// Here you should fire up a notification to let the 2 ViewControllers know that data has to be reloaded.
}
}
}
}
}
}
self.transactionArray.reverse()
self.dateArray.reverse()
self.toFromArray.reverse()
self.isDebitArray.reverse()
dump(self.toFromArray)
}
}