Why is my array always nil? - swift

Question

I really don't know whats going on and Im really confused why this happens. I might be doing something wrong but when i try to access my array out of the function, there is nothing in it. If anyone can help me please tell me.
import UIKit
class withFriendsView: UITableViewController {
var withFriendsArray:NSMutableArray = NSMutableArray()
var friendImg = [PFFile]()
var friendusername = [String]()
var friendName = [String]()
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
loadWithFriends()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return friendusername.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell:WithFriendsCell = tableView.dequeueReusableCellWithIdentifier("withFriends", forIndexPath: indexPath) as! WithFriendsCell
friendImg[indexPath.row].getDataInBackgroundWithBlock {
(data:NSData?, error:NSError?) -> Void in
let img = UIImage(data: data!)
cell.friendsImage.image = img
}
return cell
}
func loadWithFriends() {
var channelQuery = ChannelQuery.query()!
var activityQuery = ActivityQuery.query()!
channelQuery.whereKey("Host", matchesKey: "ActChannel", inQuery: activityQuery)
channelQuery.whereKey("Host", equalTo: "kia495")
var data = channelQuery.findObjects()
if data!.count != 0 {
for objects in data! {
let username = objects["Users"]!!.objectId
let predicate = NSPredicate(format: "objectId == %#", username!!)
var userQuery = PFQuery(className: "_User", predicate: predicate)
var objects = userQuery.findObjects()
for object in objects! {
friendImg.append(object.objectForKey("profileImage") as! PFFile)
}
}
}
}
}

Answer 1

You should reload the table after adding an element to the array
First move loadWithFriends() from viewDidAppear to viewDidLoad
in this line, you are returning another array, try returning friendImg.count
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return friendusername.count
}

Answer 2

This findObjectsInBackgroundWithBlock looks like an async method, which will immediately return. The code in the block will be executed only when the data is ready. So when you try to access the data from friendImg, it may not be ready and you will get nil.
If the data is not very large, you can use sync method to do this.