Swift 3 - Rearrange and persist the cells in tableview - uitableview

Question

I have a tableview which I can add items to it and it will save to core data, I can also delete these items and it all works fine
However now I want to rearrange the cells and persist the data as well
At the moment I can select the barbutton Edit and it will allow me to rearrange the cells but the moment i leave the viewcontroller it will reset to how it was
Can someone please help me?
class CustomWorkoutViewController: UIViewController {
#IBOutlet weak var newMusclesTableView: UITableView!
var workout:Workout?
override func viewDidLoad() {
super.viewDidLoad()
newMusclesTableView.delegate = self
let nib = UINib(nibName: "muscleListTableViewCell", bundle: nil)
newMusclesTableView.register(nib, forCellReuseIdentifier: "workCell")
}
override func viewDidAppear(_ animated: Bool) {
self.newMusclesTableView.reloadData()
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "addMuscles"{
guard let destination = segue.destination as? AddMusclesViewController else {
return
}
destination.workout = workout
}
else if segue.identifier == "addLogs"{
guard let destination = segue.destination as? WorkoutViewController,
let selectedRow = self.newMusclesTableView.indexPathForSelectedRow?.row else {
return
}
destination.muscleLog = workout?.muscleList?[selectedRow]
}
}
func btnAction(_ sender: UIButton) {
let point = sender.convert(CGPoint.zero, to: newMusclesTableView as UIView)
let indexPath: IndexPath! = newMusclesTableView.indexPathForRow(at: point)
let vc = viewMusclesViewController()
let viewTitle = workout?.muscleList?[indexPath.row]
vc.customInit(title: (viewTitle?.name)!)
vc.titleStr = viewTitle?.name
vc.gifStr = viewTitle?.muscleImage
navigationController?.pushViewController(vc, animated: true)
}
#IBAction func editAction(_ sender: UIBarButtonItem) {
self.newMusclesTableView.isEditing = !self.newMusclesTableView.isEditing
sender.title = (self.newMusclesTableView.isEditing) ? "Done" : "Edit"
}
func deleteMuscle(at indexPath: IndexPath){
guard let muscles = workout?.muscleList?[indexPath.row],
let managedContext = muscles.managedObjectContext else{
return
}
managedContext.delete(muscles)
do{
try managedContext.save()
newMusclesTableView.deleteRows(at: [indexPath], with: .automatic)
}catch{
print("Could not save")
newMusclesTableView.reloadRows(at: [indexPath], with: .automatic)
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
And this is my tableview extension
extension CustomWorkoutViewController: UITableViewDelegate,UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return workout?.muscleList?.count ?? 0
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 70
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = newMusclesTableView.dequeueReusableCell(withIdentifier: "muscleCell", for: indexPath) as? muscleListTableViewCell
cell?.cellView.layer.cornerRadius = (cell?.cellView.frame.height)! / 2
if let muscles = workout?.muscleList?[indexPath.row]{
cell?.muscleTitle?.text = muscles.name
cell?.myBtn.addTarget(self, action: #selector(self.btnAction(_:)), for: .touchUpInside)
}
return cell!
}
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete{
deleteMuscle(at: indexPath)
}
}
func tableView(_ tableView: UITableView, canMoveRowAt indexPath: IndexPath) -> Bool {
return true
}
func tableView(_ tableView: UITableView, moveRowAt sourceIndexPath: IndexPath, to destinationIndexPath: IndexPath) {
//How to persist data here?
}
}

Answer 1

Your code decides which item to display for a row with this code:
if let muscles = workout?.muscleList?[indexPath.row]
The row order is going to be determined by the order in muscleList. The table view can rearrange cells when you use its edit mode, but it can't save that new order because it doesn't know how to change the order of muscleList. Your implementation of tableView(_:moveRowAt:to:) needs to change the order based on the table view update.
If muscleList is an ordered relationship, change the order. If it's not an ordered relationship then you'll need to add a property that you can use to sort the relationship-- even something as simple as a sortOrder property would do.

Answer 2

I managed to find a solution to my own question
I will post it here for future if anyone needed help
func tableView(_ tableView: UITableView, moveRowAt sourceIndexPath: IndexPath, to destinationIndexPath: IndexPath) {
let muscle = workout?.muscleList?[sourceIndexPath.row]
workout?.removeFromRawMuscles(at: sourceIndexPath.row)
workout?.insertIntoRawMuscles(muscle!, at: destinationIndexPath.row)
do{
try muscle?.managedObjectContext?.save()
}catch{
print("Rows could not be saved")
}
}