Populate the data saved on core data on a tableView - ios

Question

The code of my first UIViewController looks like this and basically I want to save the data whatever I type on the UITextField and retrieve it and populate on a UITableView. code as below. (I think my issue is in the cellForRow method)
import UIKit
import CoreData
class ViewController: UIViewController {
#IBOutlet weak var textField1: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func nxtbuttonpressed(_ sender: AnyObject) {
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let context = appDelegate.persistentContainer.viewContext
//Lets save data
let newUser = NSEntityDescription.insertNewObject(forEntityName: "Expenses", into: context)
newUser.setValue(textField1.text, forKey: "expenseName")
do {
try context.save ()
print("data saved successfully")
}catch{
print("There was an error")
}
performSegue(withIdentifier: "ShowNxtVC", sender: nil)
}
}
This is where I retrieve the data that I saved in the above VC (as the code bellow). However even though I can print all the data on the console, only the last data item I saved will populate to the UITableViewCell. How can i overcome this as to populate all the data that I've saved before instead the one that i saved last.
import UIKit
import CoreData
class TableViewController: UIViewController,UITableViewDelegate,UITableViewDataSource {
#IBOutlet weak var tableView: UITableView!
var myArray : Array? = []
override func viewDidLoad() {
super.viewDidLoad()
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let context = appDelegate.persistentContainer.viewContext
let request = NSFetchRequest <NSFetchRequestResult> (entityName: "Expenses")
request.returnsObjectsAsFaults = false
do {
let results = try context.fetch(request)
// check data existance
if results.count>0 {
print(results.count)
for resultGot in results as! [NSManagedObject]{
if let expName = resultGot.value(forKey:"expenseName") as? String{
myArray = [expName]
print("my array is : \(myArray)")
}
}
}
}catch{
print("No Data to load")
}
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
print(myArray?.count)
return myArray!.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = UITableViewCell ()
cell.textLabel?.text = myArray? [indexPath.row] as! String?
return cell
}
}

Answer 1

first off all you have to change this:
myArray = [newValue] because that resets your array with just one value every time it finds a new expense in core data.
var array = [String]()
array = ["hello"]
array = ["joe"]
print(array)
// returns: ["joe"]
use:
myArray.append(newExpense)
and you get:
var array2 = [String]()
array2.append("hello")
array2.append("joe")
print(array2)
// returns: ["hello", "joe"]
After the FOR loop you add:
tableView.reloadData()
Now you should be up and running
There is another thing you should do:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "ExpCell", for: indexPath)
cell.textLabel?.text = myArray?[indexPath.row] as! String
return cell
}
In your Storyboard you need to put ExpCell as reuse identifier into the TableViewCell. The dequeReusableCell command loads only the cells you can see on your device and reuses those cells after you scrolled them out of sight. This way your app uses much less memory and will be faster.

Answer 2

update table view with data, after myArray = [expName] use
DispatchQueue.main.async { [unowned self] in
self.tableView.reloadData()
}

Answer 3

change the tableview cell for row at index path function that will solve your problem
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier identifier: String,
for indexPath: IndexPath)
if(!cell){
cell = tableView.register(tableViewCellClass,forCellReuseIdentifier identifier: String)
}
return cell
}