Duplicate cells on each load of tableView from coredata - ios

Question

The view shows duplicate rows for each record in CoreData which keep multiplying on each reload. The code is as under.
What happen is whenever I add record then I view record it shows me the record. Then I click back for the homepage after that when I click on view record I see the copy of same record. So now I have 2 same records. Can anyone please help me with and I think the problem is in table view so here is my table view controller code
import UIKit
import CoreData
var Rec = [Records]()
class TableViewController: UITableViewController {
var firstLoad = true
func nondel() -> [Records]
{
var nodellist = [Records]()
for note in Rec
{
if(note.del == nil)
{
nodellist.append(note)
}
}
return nodellist
}
override func viewDidLoad() {
super.viewDidLoad()
if(firstLoad)
{
firstLoad = false
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let context:NSManagedObjectContext = appDelegate.persistentContainer.viewContext
let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Records")
do{
let results: NSArray = try context.fetch(request) as NSArray
for result in results {
let note = result as! Records
Rec.append(note)
}
}
catch
{
print("Fetch Failed")
}
}
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "myCell") as! TableViewCell
let thisrec: Records!
thisrec = nondel()[indexPath.row]
cell.idLB.text = thisrec.id
cell.nameLB.text = thisrec.name
cell.lastLB.text = thisrec.last
cell.genderLB.text = thisrec.gender
cell.ageLB.text = thisrec.age
cell.addressLB.text = thisrec.address
return cell
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of rows
return nondel().count
}
override func viewDidAppear(_ animated: Bool) {
tableView.reloadData()
}
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath){
self.performSegue(withIdentifier: "editNote", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if(segue.identifier == "editNote")
{
let indexPath = tableView.indexPathForSelectedRow!
let recDetail = segue.destination as? AddViewController
let selectedCell: Records!
selectedCell = nondel()[indexPath.row]
recDetail!.selectedCell = selectedCell
tableView.deselectRow(at: indexPath, animated: true)
}
}
}

Answer 1

Your code is unbelievable cumbersome.
First of all never declare a data source outside of any class.
Second of all never use a function to build an array as table view data source.
Third of all firstRun is pointless because viewDidLoad is called only once anyway.
Fourth of all rather than filtering the received records manually apply a predicate to the fetch request
Further it's highly recommended to name Core Data entities always in singular form (Record) and to use the specific generic fetch request of this entity.
class TableViewController: UITableViewController {
var records = [Record]()
override func viewDidLoad() {
super.viewDidLoad()
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let context = appDelegate.persistentContainer.viewContext
let request : NSFetchRequest<Record> = Record.fetchRequest()
request.predicate = NSPredicate(format: "del != nil")
do {
records = try context.fetch(request)
} catch { print("Fetch Failed", error) }
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "myCell") as! TableViewCell
let thisrec = records[indexPath.row]
cell.idLB.text = thisrec.id
cell.nameLB.text = thisrec.name
cell.lastLB.text = thisrec.last
cell.genderLB.text = thisrec.gender
cell.ageLB.text = thisrec.age
cell.addressLB.text = thisrec.address
return cell
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return records.count
}
...