How to save data from ViewController using NSCoding in Swift [duplicate] - ios

Question

This question already has an answer here:
How to store value generated from a ViewController using NSCoding in Swift
(1 answer)
Closed 7 years ago.
I need to save data from a segued ViewController (“ScoreView.swift”) to “ScoreHistory.swift” using NSCoding. I tried but the data isn't showing up in "ScoreTableViewController.swift". What am I missing?
I have this ScoreView.swift which has the following code: (Pls note that this is a "segued" view where data has been passed from another ViewController)
class ScoreView: UIViewController {
var dateToday = NSDate()
var score: ScoreHistory?
var numberofquestions:String = ""
var scorepassed:String = ""
var scorepercentpassed:String = ""
var scoreremarkspassed:String = ""
var totalduration:String!
var incorrectanswerspassed:String = ""
var skippedquestionspassed:String = ""
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
datePlayedLabel.text = dateToday.description
totalScoreLabel.text = scorepassed
scorePercentage.text = scorepercentpassed
totalAnsweredLabel.text = numberofquestions
totalDurationLabel.text = totalduration
gameStatusLabel.text = "Exam Finished"
// NSCoding
if let score = score {
datePlayedLabel.text = score.datePlayed
totalScoreLabel.text = score.totalScore
totalAnsweredLabel.text = score.totalAnswered
totalDurationLabel.text = score.totalDuration
gameStatusLabel.text = score.gameStatus
}
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if backMenu === sender {
let datePlayed = datePlayedLabel.text ?? ""
let totalScore = totalScoreLabel.text ?? ""
let totalAnswered = totalAnsweredLabel.text ?? ""
let totalDuration = totalDurationLabel.text ?? ""
let gameStatus = gameStatusLabel.text ?? ""
// Set the score to be passed to ScoreTableViewController after the unwind segue.
score = ScoreHistory(datePlayed: datePlayed, totalScore: totalScore, totalAnswered: totalAnswered, totalDuration: totalDuration, gameStatus: gameStatus)
}
NSKeyedArchiver.archiveRootObject(score!, toFile: ScoreHistory.ArchiveURL.path!)
}
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(true)
datePlayedLabel.text = dateToday.description
totalScoreLabel.text = scorepassed
scorePercentage.text = scorepercentpassed
totalAnsweredLabel.text = numberofquestions
totalDurationLabel.text = totalduration
gameStatusLabel.text = "Exam Finished"
}
// Labels
}
}
I have ScoreHistory.swift, which has the following code:
class ScoreHistory: NSObject, NSCoding {
// MARK: Properties
var datePlayed: String
var totalScore: String
var totalAnswered: String
var totalDuration: String
var gameStatus: String
// MARK: Archiving Paths
static let DocumentsDirectory = NSFileManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask).first!
static let ArchiveURL = DocumentsDirectory.URLByAppendingPathComponent("scores")
// MARK: Types
struct PropertyKey {
static let datePlayedKey = "datePlayed"
static let totalScoreKey = "totalScore"
static let totalAnsweredKey = "totalAnswered"
static let totalDurationKey = "totalDuration"
static let gameStatusKey = "gameStatus"
}
// MARK: Initialization
init?(datePlayed: String, totalScore: String, totalAnswered: String, totalDuration: String, gameStatus: String) {
// Initialize stored properties.
self.datePlayed = datePlayed
self.totalScore = totalScore
self.totalAnswered = totalAnswered
self.totalDuration = totalDuration
self.gameStatus = gameStatus
super.init()
}
// MARK: NSCoding
func encodeWithCoder(aCoder: NSCoder) {
aCoder.encodeObject(datePlayed, forKey: PropertyKey.datePlayedKey)
aCoder.encodeObject(totalScore, forKey: PropertyKey.totalScoreKey)
aCoder.encodeObject(totalAnswered, forKey: PropertyKey.totalAnsweredKey)
aCoder.encodeObject(totalDuration, forKey: PropertyKey.totalDurationKey)
aCoder.encodeObject(gameStatus, forKey: PropertyKey.gameStatusKey)
}
required convenience init?(coder aDecoder: NSCoder) {
let datePlayed = aDecoder.decodeObjectForKey(PropertyKey.datePlayedKey) as! String
let totalScore = aDecoder.decodeObjectForKey(PropertyKey.totalScoreKey) as! String
let totalAnswered = aDecoder.decodeObjectForKey(PropertyKey.totalAnsweredKey) as! String
let totalDuration = aDecoder.decodeObjectForKey(PropertyKey.totalDurationKey) as! String
let gameStatus = aDecoder.decodeObjectForKey(PropertyKey.gameStatusKey) as! String
// Must call designated initializer.
self.init(datePlayed: datePlayed, totalScore: totalScore, totalAnswered: totalAnswered, totalDuration: totalDuration, gameStatus: gameStatus)
}
}
Here is the full code of ScoreTableViewController.swift:
class ScoreTableViewController: UITableViewController {
// MARK: Properties
var scores = [ScoreHistory]()
var dateToday = NSDate()
override func viewDidLoad() {
super.viewDidLoad()
// Load any saved scores, otherwise load sample data.
if let savedScores = loadScores() {
scores += savedScores
} else {
// Load the sample data.
loadSampleScores()
}
}
func loadSampleScores() {
let score1 = ScoreHistory(datePlayed: dateToday.description, totalScore: "0", totalAnswered: "0", totalDuration: "0", gameStatus: "started")!
scores += [score1]
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return scores.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
// Table view cells are reused and should be dequeued using a cell identifier.
let cellIdentifier = "ScoreHistoryTableViewCell"
let cell = tableView.dequeueReusableCellWithIdentifier(cellIdentifier, forIndexPath: indexPath) as! ScoreHistoryTableViewCell
// Fetches the appropriate note for the data source layout.
let score = scores[indexPath.row]
cell.datePlayedLabel.text = score.datePlayed
cell.totalScoreLabel.text = score.datePlayed
cell.totalScoreLabel.text = score.totalScore
cell.totalAnsweredLabel.text = score.totalAnswered
cell.totalDurationLabel.text = score.totalDuration
cell.gameStatusLabel.text = score.gameStatus
return cell
}
// Override to support conditional editing of the table view.
override func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -> Bool {
// Return false if you do not want the specified item to be editable.
return true
}
// Override to support editing the table view.
override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
if editingStyle == .Delete {
// Delete the row from the data source
scores.removeAtIndex(indexPath.row)
saveScores()
tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
}
}
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "ShowDetail" {
let scoreDetailViewController = segue.destinationViewController as! ScoreViewController
// Get the cell that generated this segue.
if let selectedScoreCell = sender as? ScoreHistoryTableViewCell {
let indexPath = tableView.indexPathForCell(selectedScoreCell)!
let selectedScore = scores[indexPath.row]
scoreDetailViewController.score = selectedScore
}
}
}
// MARK: NSCoding
func saveScores() {
let isSuccessfulSave = NSKeyedArchiver.archiveRootObject(scores, toFile: ScoreHistory.ArchiveURL.path!)
if !isSuccessfulSave {
print("Failed to save scores...")
}
}
func loadScores() -> [ScoreHistory]? {
return NSKeyedUnarchiver.unarchiveObjectWithFile(ScoreHistory.ArchiveURL.path!) as? [ScoreHistory]
}
#IBAction func unwindToScoreList(sender: UIStoryboardSegue) {
if let sourceViewController = sender.sourceViewController as? ScoreViewController, score = sourceViewController.score {
if let selectedIndexPath = tableView.indexPathForSelectedRow {
// Update an existing note.
scores[selectedIndexPath.row] = score
tableView.reloadRowsAtIndexPaths([selectedIndexPath], withRowAnimation: .None)
// Add a new score.
let newIndexPath = NSIndexPath(forRow: scores.count, inSection: 0)
scores.append(score)
tableView.insertRowsAtIndexPaths([newIndexPath], withRowAnimation: .Bottom)
saveScores()
}
}
}
}
GOAL: My goal is to record/store all session data from “ScoreView.swift” whenever a user finishes a quiz game.
The "ScoreView" is shown after each quiz game, I plan to record each quiz results in "ScoreHistory.swift." How do I do it?

Answer 1

The easiest solution is to save the changed values from the UITextField instances back to the score instance in ScoreView (why is score optional at all since you always pass a non-optional score instance ??) and unwind the segue.
Then the array is saved in the method unwindToScoreList of ScoreTableViewController
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if backMenu === sender {
score?.datePlayed = datePlayedLabel.text ?? ""
score?.totalScore = totalScoreLabel.text ?? ""
score?.totalAnswered = totalAnsweredLabel.text ?? ""
score?.totalDuration = totalDurationLabel.text ?? ""
score?.gameStatus = gameStatusLabel.text ?? ""
}
}
No archiving in ScoreView !

Answer 2

Your loadScores function is loading an archived array of scores:
func loadScores() -> [ScoreHistory]? {
return NSKeyedUnarchiver.unarchiveObjectWithFile(ScoreHistory.ArchiveURL.path!) as? [ScoreHistory]
}
In your segue, you are only archiving a single score. You can't archive a ScoreHistory instance and expect to unarchive a ScoreHistory array. Where you currently have:
score = ScoreHistory(datePlayed: datePlayed, totalScore: totalScore, totalAnswered: totalAnswered, totalDuration: totalDuration, gameStatus: gameStatus)
You need to change this to:
var scores = loadScores() ?? []
score = ScoreHistory(datePlayed: datePlayed, totalScore: totalScore, totalAnswered: totalAnswered, totalDuration: totalDuration, gameStatus: gameStatus)
scores.append(score)
saveScores(scores)
Where loadScores and saveScores are the same as the code in ScoreTableViewController, although I've added the scores to save as a parameter given this code creates a local var.
UPDATE: It's late and I wasn't paying enough attention. You need to handle loadScores returning nil, and of course scores should be var not let or you won't be able to add to it. With these changes, scores should no longer be optional, so you won't need to unwrap it.