UITableview crashes when scrolling up in Swift - swift

Question

I am having this crash when trying to scroll up my tableview. My array is not nil. Why does it crash every time I try to scroll up? I am trying to display data from Core Data.
Here is my code:
var product = [NSManagedObject]()
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int
{
return product.count
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
{
let cellIdentifier = "CheckOutTableViewCell"
let cell = tableView.dequeueReusableCellWithIdentifier(cellIdentifier, forIndexPath: indexPath) as! CheckOutTableViewCell
let item = product[indexPath.row]
** It crashes here, every time I try to scroll up my table view
cell.productTitle.text = item.valueForKey("name") as! String
cell.productDescription.text = item.valueForKey("size") as! String
return cell
}
func fetch() {
let moc = DataController().managedObjectContext
let productFetch = NSFetchRequest(entityName: "Product")
do {
let fetchedResults: [NSManagedObject] = try moc.executeFetchRequest(productFetch) as! [Product]
if let results: [NSManagedObject] = fetchedResults {
product = results
print("results:\(results.count)")
}
} catch let error as NSError {
print("Error: \(error.localizedDescription)")
}
}
Product.swift
import Foundation
import CoreData
class Product: NSManagedObject {
}
Product+CoreDataProperties.swift
import Foundation
import CoreData
extension Product {
#NSManaged var id: String?
#NSManaged var name: String?
#NSManaged var img: String?
#NSManaged var quantity: String?
#NSManaged var size: String?
#NSManaged var price: String?
#NSManaged var promo: String?
}
Crash Screenshot

Answer 1

You should check the size of the array before getting your product, and use optional binding (if let) to check that the value exists in the dictionary:
if indexPath.row < product.count {
let item = product[indexPath.row]
if let name = item.valueForKey("name") as? String {
cell.productTitle.text = name
}
if let size = item.valueForKey("size") as? String {
cell.productDescription.text = size
}
}
To write safer code, it's a good idea to avoid force unwrapping when possible.
In this case, given that you have a Product class for your model, you should store your products as [Product], you can then avoid using valueForKey:
if indexPath.row < product.count {
let item = product[indexPath.row]
if let name = item.name as? String {
cell.productTitle.text = name
}
if let size = item.size as? String {
cell.productDescription.text = size
}
}