How to save array data locally - swift

Question

Here is my code. I want to learn how to save my dataSource for the like button of each cell. So that when the user leaves the app and returns later, the same cells that were liked remain liked.
This is new code from my last post. Since I don't want to keep making new arrays, I can try and locally save my dataSource variable which stores each cells Status of being liked or not.
ViewController -
import UIKit
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
#IBOutlet var tableView: UITableView!
var dataSource: [TableModel] = []
var updatedCell = TableViewCell()
var updatedIndex = Int()
override func viewDidLoad() {
super.viewDidLoad()
overrideUserInterfaceStyle = .light
self.dataSource = Array(repeating: TableModel(isLiked: false), count: 8)
self.tableView.delegate = self
self.tableView.dataSource = self
self.tableView.showsVerticalScrollIndicator = false
self.tableView.reloadData()
}
#IBAction func buttonSelected(_ sender: Any) {
// Update Cell for which UIButton (Like Button) was tapped.
dataSource[(sender as AnyObject).tag].isLiked = !dataSource[(sender as AnyObject).tag].isLiked
let indexPath = IndexPath(row: (sender as AnyObject).tag, section: 0)
tableView.reloadRows(at: [indexPath], with: .automatic)
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
tableView.deselectRow(at: indexPath, animated: true)
// Saved updatedCell & updatedIndex variables for delegate pattern. To Update this VC's cells data when edited on secondVC (moreInfoViewController) in a way, made them accessible outside this function
// To Get Specific TableView Cell the user is interacting with.
updatedCell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! TableViewCell
updatedIndex = indexPath.row
// Go to Second VC and Send cell tapped data to next view
let vc = (storyboard?.instantiateViewController(identifier: "secondVC") as? moreInfoViewController)!
vc.delegate = self
// Get Status of Liked Button in the cell the user tapped and display if the user liked it previously in the SecondVC
let isLiked = dataSource[indexPath.row].isLiked
if isLiked {
// print("Liked")
vc.isLiked = true
} else {
// print("Not Liked")
vc.isLiked = false
}
present(vc, animated: true)
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 8
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! TableViewCell
// cell.moreBtn.isUserInteractionEnabled = false
cell.likeBtn.tag = indexPath.row
// cell.likeBtn.addTarget(self, action: #selector(buttonSelected(_:)), for: .touchUpInside)
// Get Each Cell Liked Button Status and display if the user liked or not Liked each cell
let isLiked = dataSource[indexPath.row].isLiked
if isLiked {
// User liked the post
cell.likeBtn.setImage(UIImage(named: "liked"), for: UIControl.State.normal)
} else {
// User Unliked the post
cell.likeBtn.setImage(UIImage(named: "unLiked"), for: UIControl.State.normal)
}
return cell
}
}
// Conform VC to protocol (VC2Delegate) located in "Structs.swift" File
extension ViewController: VC2Delegate {
func likeStatusDidChange(_ vc2: moreInfoViewController, to title: Bool) {
// set the text of the table cell here...
dataSource[updatedIndex].isLiked = !dataSource[updatedIndex].isLiked
let indexPath = IndexPath(row: updatedIndex, section: 0)
tableView.reloadRows(at: [indexPath], with: .automatic)
}
}
moreInfoViewController -
import UIKit
class moreInfoViewController: UIViewController {
#IBOutlet var backBtn: UIButton!
#IBOutlet var titleLabel: UILabel!
#IBOutlet var locationLabel: UILabel!
#IBOutlet var theImage: UIImageView!
#IBOutlet var mainlikeBtn: UIButton!
#IBOutlet var mainTypeLbl: UILabel!
var currentID:String = ""
var isLiked = Bool()
weak var delegate: VC2Delegate?
override func viewDidLoad() {
super.viewDidLoad()
overrideUserInterfaceStyle = .light
self.navigationController?.setNavigationBarHidden(true, animated: true)
styles()
// "isLiked" variable to display whether or user liked this event
if (isLiked == true) {
// is Liked
mainlikeBtn.setImage(UIImage(named: "liked"), for: UIControl.State.normal)
} else {
// Not Liked
mainlikeBtn.setImage(UIImage(named: "unLiked"), for: UIControl.State.normal)
}
}
// Heart/Like Button Action. User can like event in this VC with this button and it will tell the firstVC (ViewController) to update "Like Status" there also
#IBAction func likeBtnAction(_ sender: Any) {
if (isLiked == true) {
// is Liked
isLiked = false
mainlikeBtn.setImage(UIImage(named: "unLiked"), for: UIControl.State.normal)
} else {
isLiked = true
mainlikeBtn.setImage(UIImage(named: "liked"), for: UIControl.State.normal)
}
// When User interacts with like Button, this function gets called that tells the firstVC (ViewController) to update as well.
// likeStatusDidChange function is located at the bottom of the (ViewController) with extension ViewController.
delegate?.likeStatusDidChange(self, to: true)
}
// Go Back To FirstVC (ViewController)
#IBAction func previousVC(_ sender: Any) {
dismiss(animated: true, completion: nil)
}
func styles() {
titleLabel.numberOfLines = 1
titleLabel.adjustsFontSizeToFitWidth = true
locationLabel.numberOfLines = 1
locationLabel.adjustsFontSizeToFitWidth = true
backBtn.transform = CGAffineTransform(rotationAngle: -CGFloat.pi / 2)
theImage.layer.borderColor = UIColor.black.cgColor
theImage.layer.borderWidth = 2
theImage.layer.cornerRadius = 10
}
}

Answer 1

When you get array from userdefaults it gives you Any type array so you need to cast it to Int array and check it nil or not before you use. So you can use this code block.
if let savedDataKey = UserDefaults.standard.array(forKey: "savedDataKey") as? [Int] {
print(savedDataKey)
}