Swift - can't reload Data from TableView after add button action - ios

Question

I'm new to Swift and need your help.
I created a TableViewController with a custom cell.
Also I created a "add" Button in navigation bar to add a new value to my tableview.
Saving the values in Core Data and fetch them in viewWillAppear.
When pressing the add button a UIAlertController shows up which i had customized like i needed. I added a cancel action and a ok action but when i press the ok button from the alert the new value don't shows up in my tableview. I have to switch to an other viewcontroller that the tableview shows it.
I added groupsTableView.reloadData()on different points in my code but cant get it to work.
Hope someone can help me out!
Code from MasterViewController:
import UIKit
import CoreData
class MasterViewController: UITableViewController {
var groups: [Groups] = []
#IBOutlet weak var groupsTableView: UITableView!
var groupsTextField: UITextField?
override func viewDidLoad() {
super.viewDidLoad()
groupsTableView.delegate = self
groupsTableView.dataSource = self
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
override func viewWillAppear(_ animated: Bool) {
// Core date initialization
guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else {
return
}
let managedContext = appDelegate.persistentContainer.viewContext
let fetchRequest: NSFetchRequest<Groups> = Groups.fetchRequest()
do {
groups = try managedContext.fetch(fetchRequest)
groupsTableView.reloadData()
} catch {
// TODO: error handling
print("Could not fetch groups")
}
navigationItem.leftBarButtonItem = editButtonItem
let addButton = UIBarButtonItem(barButtonSystemItem: .add, target: self, action: #selector(insertNewObject))
navigationItem.rightBarButtonItem = addButton
}
// MARK: - add new Group
#objc func insertNewObject() {
let addButtonAlert = UIAlertController(title: "Neue Gruppe", message: "Füge eine neue Gruppe deiner Liste hinzu", preferredStyle: .alert)
addButtonAlert.addTextField { (UITextField) in
self.groupsTextField = UITextField
self.groupsTextField?.placeholder = "Name der Gruppe"
self.groupsTextField?.clearButtonMode = .whileEditing
}
let okAction = UIAlertAction(title: "Hinzufügen", style: .default, handler: addNewGroup)
let cancelAction = UIAlertAction(title: "Abbrechen", style: .cancel, handler: nil)
addButtonAlert.addAction(okAction)
addButtonAlert.addAction(cancelAction)
self.present(addButtonAlert, animated: true, completion: nil)
}
func addNewGroup(_:UIAlertAction) -> Void {
let group = Groups(groupId: UUID(), groupTitle: groupsTextField!.text ?? "")
do {
try group?.managedObjectContext?.save()
groupsTableView.reloadData()
} catch {
// TODO: error handling
print("Could not save group")
}
}
// MARK: - Segue
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
guard let destination = segue.destination as? DetailViewController,
let selectedRow = self.groupsTableView.indexPathForSelectedRow?.row else {
return
}
destination.group = groups[selectedRow]
destination.title = groups[selectedRow].groupTitle
}
// MARK: - delete Group
func deleteGroup(at indexPath: IndexPath) {
let group = groups[indexPath.row]
guard let managedContext = group.managedObjectContext else {
return
}
managedContext.delete(group)
do {
try managedContext.save()
groups.remove(at: indexPath.row)
groupsTableView.deleteRows(at: [indexPath], with: .automatic)
} catch {
//TODO: error handling
print("Could not delete Group")
groupsTableView.reloadRows(at: [indexPath], with: .automatic)
}
}
// MARK: - Table View
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return groups.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = groupsTableView.dequeueReusableCell(withIdentifier: "GroupsTableViewCell", for: indexPath) as! GroupsTableViewCell
let object = groups[indexPath.row]
cell.groupTitleLabel?.text = object.groupTitle
return cell
}
override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
// Return false if you do not want the specified item to be editable.
return true
}
override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete {
deleteGroup(at: indexPath)
}
}
}

Answer 1

Add group item to your groups array and after that reload your tableview as shown below:-
func addNewGroup(_:UIAlertAction) -> Void {
let group = Groups(groupId: UUID(), groupTitle: groupsTextField!.text ?? "")
do {
try group?.managedObjectContext?.save()
self.groups.append(group)
groupsTableView.reloadData()
} catch {
// TODO: error handling
print("Could not save group")
}
}