SWIFT: Parse column is not appending into array - ios

Question

I'd like to append the 'userVotes' column in the following parse table into an array using Swift -
Here is my code -
import UIKit
import Parse
class MusicPlaylistTableViewController: UITableViewController {
var usernames = [String]()
var songs = [String]()
var voters = [String]()
var numVotes = 0
override func viewDidLoad() {
super.viewDidLoad()
tableView.separatorColor = UIColor.grayColor()
let query = PFQuery(className:"PlaylistData")
query.findObjectsInBackgroundWithBlock { (objects: [PFObject]?, error: NSError?) -> Void in
if error == nil {
if let objects = objects! as? [PFObject] {
self.usernames.removeAll()
self.songs.removeAll()
self.voters.removeAll()
for object in objects {
let username = object["username"] as? String
self.usernames.append(username!)
let track = object["song"] as? String
self.songs.append(track!)
let title = object["userVotes"]! as? String
self.voters.append(title!)
print("Array: \(self.voters)")
}
self.tableView.reloadData()
}
} else {
print(error)
}
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
// #warning Incomplete implementation, return the number of sections
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of rows
return usernames.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("CellTrack", forIndexPath: indexPath) as! TrackTableViewCell
//cell.username.text = usernames[indexPath.row]
cell.username.text = usernames[indexPath.row]
cell.songTitle.text = songs[indexPath.row]
cell.votes.text = "\(numVotes)"
cell.selectionStyle = UITableViewCellSelectionStyle.None
return cell
}
override func tableView(tableView: UITableView, didDeselectRowAtIndexPath indexPath: NSIndexPath) {
}
}
I would like the parse array column to append as follows -
[["user1,"user5,"user9"],["user1,"user2,"user3"],["user4,"user5,"user6"],...]
At this point, I'm getting the following runtime error - fatal error: unexpectedly found nil while unwrapping an Optional value

Answer 1

Since each object that is in your "userVotes" is an array and your you've declared
var voters = [String]()
which is not right because you're saying that there will be one element being appended which is not the case.
So, you should declare voters as...
var voters = Array<Array<String>>()
then as you are downloading it,
for object in objects {
let title = object["userVotes"]! as? [String]
self.voters.append(title!)
print("Array: \(self.voters)")
}