I have an empty array set as a global variable that is populated with array items from a tableview. This is used to populate another tableview. This data needs to persist so that when the user returns to the app, their tableview data is in the same state they left it, i.e. populate with data from the array.
Though I've looked for dozens of tutorials and examples. I've also hacked at it myself to make it work and every time I reload the app, the array is empty. How can I get that global variable array to hold onto it's array data?
var sharedData = [String]()
This is my 1st VC where I have setup functions for the UserDefaults. And I've executed my saveArray() func every time a change is made to the array. I've then executed retrieveArray() func every time I need to load from the array.
import UIKit
var sharedData = [String]()
struct Keys {
static let arrayKey = "arrayKey"
}
let defaults = UserDefaults.standard
func saveArray() {
defaults.set(sharedData, forKey: Keys.arrayKey)
}
func retrieveArray() {
var savedData = defaults.object(forKey: Keys.arrayKey) as? [String] ?? []
savedData.append(contentsOf: sharedData)
}
class ViewController: UIViewController {
var effect:UIVisualEffect!
@IBOutlet weak var searchBar: UISearchBar!
@IBOutlet var tableView: UITableView!
@IBOutlet weak var activityIndicator: UIActivityIndicatorView!
@IBOutlet weak var visualEffectView: UIVisualEffectView!
let materialData = ["One", "Two", "Three", "Four"]
var searchMaterial = [String]()
var searching = false
@IBAction func favoritesButtonArrayUpdate(_ sender: UIBarButtonItem) {
print(sharedData)
}
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
saveArray()
retrieveArray()
print(sharedData)
}
extension ViewController: UITableViewDelegate {
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
tableView.deselectRow(at: indexPath, animated: true)
print(self.materialData[indexPath.row], "selected!")
}
func tableView(_ tableView: UITableView, editActionsForRowAt indexPath: IndexPath) -> [UITableViewRowAction]? {
let favorite = UITableViewRowAction(style: .default, title: "Favorite") { (action, indexPath) in
var data: String
if self.searching {
data = self.searchMaterial[indexPath.row]
} else {
data = self.materialData[indexPath.row]
}
sharedData.append(data)
saveArray()
print(sharedData)
}
favorite.backgroundColor = UIColor.orange
return [favorite]
}
}
This is my 2nd VC which displays the array data stored in the global variable array sharedData. I've again added all the func when making changes to the array and pulling data from the array.
import UIKit
class FavoritesViewController: UIViewController {
@IBOutlet var tableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
saveArray()
retrieveArray()
}
}
extension FavoritesViewController: UITableViewDelegate, UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
retrieveArray()
return sharedData.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
retrieveArray()
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
cell.textLabel?.numberOfLines = 0
cell.textLabel?.text = sharedData[indexPath.row]
return cell
}
func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
return true
}
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete {
sharedData.remove(at: indexPath.row)
saveArray()
tableView.beginUpdates()
tableView.deleteRows(at: [indexPath], with: .automatic)
tableView.endUpdates()
}
}
}
