Joe Joe - 2 months ago 8
Swift Question

Saving TableView Array at indexPath in Swift

I have two tableView running in my project.I have successfully passed data from my first tableView to second tableView controller using segue.I am trying to save the data which i passed to secondViewController using NSUserDefaults.My partial code below....

First VC:

var tableView: UITableView!
var DataArray = ["Bus","Helicopter","Truck","Boat","Bicycle","Motorcycle","Plane","Train","Car","S cooter","Caravan"]
var sendSelectedData = NSString()


override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let indexPath = tableView.indexPathForSelectedRow!
let currentCell = tableView.cellForRow(at: indexPath) as UITableViewCell!
// print(indexPath)
// print(currentCell)

sendSelectedData = (currentCell!.textLabel?.text)! as String as NSString
performSegue(withIdentifier: "ShowDetails", sender: indexPath)

}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

let selectedIndex = sender as! NSIndexPath
let currentCell = tableView.cellForRow(at: selectedIndex as IndexPath)!
self.sendSelectedData = (currentCell.textLabel?.text)! as String as NSString
if segue.identifier == "ShowDetails" {

let viewController = segue.destination as! SecondController
viewController.newItem = (self.sendSelectedData as String)

}
}


Second VC:

var NewArray = [""]

var newItem: String = ""

override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.

NewArray.insert(newItem, at: Array.count)
self.tableView?.beginUpdates()

// NewArray.append(newItem)

let defaults = UserDefaults.standard
defaults.object(forKey: "NewArray")

self.tableView?.endUpdates()
}

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as UITableViewCell

cell.textLabel?.text = NewArray[(indexPath as NSIndexPath).row] as String
return cell
}

func insertRowsAtIndexPaths(indexPaths: [AnyObject], withRowAnimation animation: UITableViewRowAnimation) {
}

func reloadRowsAtIndexPaths(indexPaths: [AnyObject], withRowAnimation animation: UITableViewRowAnimation) {

}


I am following https://grokswift.com/uitableview-updates/ article to achieve the function....

Thanks in Advance.

Answer

In AppDelegate applicationDidFinishLaunching register an empty array as default value for the key "NewArray".

let defaultValues = ["NewArray": [String]()]
UserDefaults.standard.register(defaults: defaultValues)

In Second VC define newArray (variable names are supposed to start with a lowercase letter) also as empty String array

var newArray = [String]()

In viewDidLoad retrieve the array from user defaults, append the new item, save the array back to user defaults and reload the table view

override func viewDidLoad() {
  super.viewDidLoad()

  let defaults = UserDefaults.standard
  newArray = defaults.array(forKey: "NewArray") as! [String]
  newArray.append(newItem)
  defaults.set(newArray, forKey: "NewArray")
  self.tableView?.reloadData()
}

beginUpdates(), endUpdates() and insertRowsAtIndexPath / reloadRowsAtIndexPaths are not needed at all.