indexPath.row not getting data from the array

Question

I've created a PFQuery to get some strings from my parse server and the put this in a couple of arrays

var packsAvailable = [""]
var packsImage = [""]
var packsDescription = [""]

If I print the value of the array in the for loop of the query I get all the values in a proper array. However when I try and use this information to populate my collection view nothing happens. I can't figure this out because it works with the manually created arrays tableImages and tableData that I have commented out for testing.

import UIKit
import Parse

private let reuseIdentifier = "Cell"

class CollectionViewController: UICollectionViewController {

//var tableData: [String] = ["Tis is a description", "Test 22", "Test 33"]
//var tableImages: [String] = ["walk1bg", "2", "walk3bg"]


var packsAvailable = [""]  // the total packs in the app
var packsImage = [""]
var packsDescription = [""]

override func viewDidLoad() {
    super.viewDidLoad()


    let packQuery = PFQuery(className: "Pack")

    packQuery.findObjectsInBackground(block: { (objectsArray, error) in
        if error != nil {
            print(error!)
        } else if let packs = objectsArray {
            self.packsAvailable.removeAll() // remove them incase they double up

            print(packs.count)
            for object in packs {
                /*
                print(object["packName"])
                print(object["packImage"])
                print(object["packDesctription"])
                */
                self.packsAvailable.append(object["packName"] as! String)
                self.packsImage.append(object["packImage"] as! String)
                self.packsDescription.append(object["packDesctription"] as! String)

                /*
                print(self.packsAvailable)
                print(self.packsImage)
                print(self.packsDescription)
                */
            }
        }
    })
}



override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()

}


// MARK: UICollectionViewDataSource

override func numberOfSections(in collectionView: UICollectionView) -> Int {
    return 1
}


override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return packsAvailable.count
}


func UIColorFromHEX(hexValue: UInt) -> UIColor {
    return UIColor(
        red: CGFloat((hexValue & 0xFF0000) >> 16) / 255.0,
        green: CGFloat((hexValue & 0x00FF00) >> 8) / 255.0,
        blue: CGFloat(hexValue & 0x0000FF) / 255.0,
        alpha: CGFloat(1.0)
    )
}


override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell: CollectionViewCell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath) as! CollectionViewCell

    //cell.labelCell.text = tableData[indexPath.row]
    //cell.imageCell.image = UIImage(named: tableImages[indexPath.row])

    cell.labelCell.text = packsDescription[indexPath.row]

    print(packsDescription[indexPath.row])

    cell.imageCell.image = UIImage(named: packsImage[indexPath.row])

    cell.imageCell.layer.masksToBounds = true
    cell.imageCell.layer.cornerRadius = cell.imageCell.frame.height/2

    cell.imageCell.layer.borderWidth = 3
    cell.imageCell.layer.borderColor = UIColorFromHEX(hexValue: 0x62aca2).cgColor

    return cell

}

override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    print("Selected \(indexPath.row)")
}

}

Answer 1

add collectionView.reloadData() after the for-in loop is completed inside your closure. This will tell your collectionView to fetch the current array values.

Answer 2

You forgot to reload the collectionView when the response comes from the server. just add collectionView.reloadData() after completion of for loop

override func viewDidLoad() {
        super.viewDidLoad()

    let packQuery = PFQuery(className: "Pack")

    packQuery.findObjectsInBackground(block: { (objectsArray, error) in
        if error != nil {
            print(error!)
        } else if let packs = objectsArray {
            self.packsAvailable.removeAll() // remove them incase they double up

            print(packs.count)
            for object in packs {
                /*
                print(object["packName"])
                print(object["packImage"])
                print(object["packDesctription"])
                */
                self.packsAvailable.append(object["packName"] as! String)
                self.packsImage.append(object["packImage"] as! String)
                self.packsDescription.append(object["packDesctription"] as! String)

                /*
                print(self.packsAvailable)
                print(self.packsImage)
                print(self.packsDescription)
                */
            }

                //swift 2.3
                dispatch_async(dispatch_get_main_queue()) { 
                  self.collectionView.reloadData()
                }

                //swift 3
                /* DispatchQueue.main.async {
                 self.collectionView.reloadData()
                }*/
        }
    })

}