cellForItemAtIndexPath not being called, unclear as to why - ios

Question

I've read a few other questions on this that the problem related to the size of the CollectionView. I've tried adjusting the size as recommended in those answers, but none of them were working. I'm using a NSFetchedResultsController which convolutes it for me as well (I'm wondering if it has something to do with it not firing).
Anyways, the real problem is I have no content appearing for my UICollectionView. There are no errors at runtime, simply a blank screen. I'm working in Swift (obviously).
Here is my code from the ViewController:
import UIKit
import CoreData
private let reuseIdentifier = "Family"
private var selectedFirstName:String = "Blank"
private var selectedLastName:String = "Blank"
private var selectedNumber:String = "Blank"
private var selectedEmail:String = "Blank"
class FamilyViewController: UIViewController, UICollectionViewDataSource {
var coreDataStack: CoreDataStack!
var fetchedResultsController: NSFetchedResultsController!
#IBOutlet var familyCollectionView: UICollectionView!
override func viewDidLoad() {
super.viewDidLoad()
//1
let fetchRequest = NSFetchRequest(entityName: "Family")
let firstNameSort =
NSSortDescriptor(key: "firstName", ascending: true)
fetchRequest.sortDescriptors = [firstNameSort]
//2
self.coreDataStack = CoreDataStack()
fetchedResultsController =
NSFetchedResultsController(fetchRequest: fetchRequest,
managedObjectContext: coreDataStack.context,
sectionNameKeyPath: nil,
cacheName: nil)
fetchedResultsController.delegate = CollectionViewFetchedResultsControllerDelegate(collectionView: familyCollectionView)
//3
do {
try fetchedResultsController.performFetch()
} catch let error as NSError {
print("Error: \(error.localizedDescription)")
}
}
func configureCell(cell: FamilyCCell, indexPath: NSIndexPath) { let family = fetchedResultsController.objectAtIndexPath(indexPath) as! Family
cell.firstNameLabel.text = family.firstName
print("configureCell ran")
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
// #warning Incomplete implementation, return the number of sections
print("numberOfSectionsInCollectionView ran")
return fetchedResultsController.sections!.count
}
func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of items
let sectionInfo = fetchedResultsController.sections![section]
print("numberOfItemsInSection ran")
return sectionInfo.numberOfObjects
}
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier, forIndexPath: indexPath) as! FamilyCCell
print("cellForItemAtIndexPath ran")
configureCell(cell, indexPath: indexPath)
return cell
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if (segue.identifier == "showDetail") {
let detailVC = segue.destinationViewController as! ContactViewController
print("prepareForSegue ran")
detailVC.detailFirstName = selectedFirstName
detailVC.detailLastName = selectedLastName
detailVC.detailNumber = selectedNumber
detailVC.detailEmail = selectedEmail
}
}
}
extension FamilyViewController: UICollectionViewDelegate {
func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
print("didSelectItemAtIndexPath ran")
collectionView.delegate = self
let family = fetchedResultsController.objectAtIndexPath(indexPath) as! Family
selectedFirstName = family.firstName!
selectedLastName = family.lastName!
selectedNumber = family.phone!
selectedEmail = family.email!
coreDataStack.saveContext()
}
}
class CollectionViewFetchedResultsControllerDelegate: NSObject, NSFetchedResultsControllerDelegate {
// MARK: Properties
private let collectionView: UICollectionView
private var blockOperations: [NSBlockOperation] = []
// MARK: Init
init(collectionView: UICollectionView) {
self.collectionView = collectionView
}
// MARK: Deinit
deinit {
blockOperations.forEach { $0.cancel() }
blockOperations.removeAll(keepCapacity: false)
}
// MARK: NSFetchedResultsControllerDelegate
func controllerWillChangeContent(controller: NSFetchedResultsController) {
blockOperations.removeAll(keepCapacity: false)
}
func controller(controller: NSFetchedResultsController, didChangeObject anObject: AnyObject, atIndexPath indexPath: NSIndexPath?, forChangeType type: NSFetchedResultsChangeType, newIndexPath: NSIndexPath?) {
switch type {
case .Insert:
guard let newIndexPath = newIndexPath else { return }
let op = NSBlockOperation { [weak self] in self?.collectionView.insertItemsAtIndexPaths([newIndexPath]) }
blockOperations.append(op)
case .Update:
guard let newIndexPath = newIndexPath else { return }
let op = NSBlockOperation { [weak self] in self?.collectionView.reloadItemsAtIndexPaths([newIndexPath]) }
blockOperations.append(op)
case .Move:
guard let indexPath = indexPath else { return }
guard let newIndexPath = newIndexPath else { return }
let op = NSBlockOperation { [weak self] in self?.collectionView.moveItemAtIndexPath(indexPath, toIndexPath: newIndexPath) }
blockOperations.append(op)
case .Delete:
guard let indexPath = indexPath else { return }
let op = NSBlockOperation { [weak self] in self?.collectionView.deleteItemsAtIndexPaths([indexPath]) }
blockOperations.append(op)
}
}
func controller(controller: NSFetchedResultsController, didChangeSection sectionInfo: NSFetchedResultsSectionInfo, atIndex sectionIndex: Int, forChangeType type: NSFetchedResultsChangeType) {
switch type {
case .Insert:
let op = NSBlockOperation { [weak self] in self?.collectionView.insertSections(NSIndexSet(index: sectionIndex)) }
blockOperations.append(op)
case .Update:
let op = NSBlockOperation { [weak self] in self?.collectionView.reloadSections(NSIndexSet(index: sectionIndex)) }
blockOperations.append(op)
case .Delete:
let op = NSBlockOperation { [weak self] in self?.collectionView.deleteSections(NSIndexSet(index: sectionIndex)) }
blockOperations.append(op)
default: break
}
}
func controllerDidChangeContent(controller: NSFetchedResultsController) {
collectionView.performBatchUpdates({
self.blockOperations.forEach { $0.start() }
}, completion: { finished in
self.blockOperations.removeAll(keepCapacity: false)
})
}
}
I have print statements confirming that the cellForItemAtIndexPath is not running. Any ideas? I realize this is quite specific and I gave a crap ton of code, just not quite sure where the error could be coming from. Thanks for any help in advance.

Answer 1

Make sure...you Confirm UICollectionViewDelegate protocol methods.
set collectionview.delegate = self
collectionview.datasource = self

Answer 2

in the collection view datasource for the methods numberOfSectionsInCollectionView return 1 and in collectionViewNumberOfCellsForSection return the number of cells you want to display
to clarify on tableview or a collection view a "section" is a group of related things where as a cell (or row for tableview) are the actual things you want to display - when you do not override the amount of cells required it will return 0 for all sections
(ill check the exact method signatures in the morning and edit if they are slightly off)

Answer 3

Write it:
class FamilyViewController: UIViewController, UICollectionViewDataSource,UICollectionViewDelegate{
and write these two lines in your viewDidLoad method:
familyCollectionView.delegate = self
familyCollectionView.datasource = self