Swift's deinit is not called - swift

Question

private let DBItemCellIdentifier = "ItemCellIdentifier"
private let DBItemSegueIdentifier = "ItemSegueIdentifier"
class DBItemsViewController: UIViewController, UITableViewDataSource, UITableViewDelegate, DBItemTableViewCellDelegate {
#IBOutlet weak var tableView: UITableView!
#IBOutlet weak var previousButton: UIButton!
#IBOutlet weak var nextButton: UIButton!
#IBOutlet weak var categoryNameLabel: UILabel!
private var elements = [Any]()
private var currentItemIndex = 0
private var isFetching = false
private weak var currentCategory: DBCategory? {
didSet {
updateView()
}
}
var categories = [DBCategory]()
var currentCategoryIndex = 0
//MARK: - Class Methods
//MARK: - Initialization
override func viewDidLoad() {
super.viewDidLoad()
tableView.rowHeight = UITableViewAutomaticDimension
tableView.estimatedRowHeight = 100.0
tableView.tableFooterView = UIView(frame: CGRectZero)
setupUserAndCartButtons()
fetchItems()
}
deinit {
print("deinit")
}
//MARK: - Actions
#IBAction func nextButtonTapped(sender: UIButton) {
currentCategoryIndex = min(currentCategoryIndex + 1, categories.count - 1)
fetchItems()
}
#IBAction func previousButtonTapped(sender: UIButton) {
currentCategoryIndex = max(currentCategoryIndex - 1, 0)
fetchItems()
}
//MARK: - Private
private func fetchItems() {
tableView.alpha = 0
currentCategory = nil
if !categories.isEmpty && !isFetching {
let category = categories[currentCategoryIndex]
currentCategory = DBCategory.findCategoryWithIdentifier(category.identifier)
if currentCategory == nil {
SVProgressHUD.show()
}
isFetching = true
DBNetworkClient.sharedClient().itemsForCategory(category, completionBlock: { error in
defer {
self.isFetching = false
SVProgressHUD.dismiss()
UIAlertController.showAlertFromError(error)
}
self.currentCategory = DBCategory.findCategoryWithIdentifier(category.identifier)
})
}
}
private func updateView() {
let category = categories[currentCategoryIndex]
title = category.menu.location.name
categoryNameLabel.text = category.name
previousButton.hidden = currentCategoryIndex == 0 ? true : false
nextButton.hidden = currentCategoryIndex == categories.count - 1 ? true : false
prepareElements()
tableView.reloadData()
UIView.animateWithDuration(0.5, animations: {
self.tableView.alpha = 1
})
}
private func prepareElements() {
elements.removeAll(keepCapacity: false)
if let items = currentCategory?.items {
for item in items {
elements.append(item)
}
}
if let sets = currentCategory?.sets {
for set in sets {
elements.append(set)
}
}
elements.sortInPlace {
let left = ($0 as? DBSet)?.position ?? ($0 as? DBItem)?.position
let right = ($1 as? DBSet)?.position ?? ($1 as? DBItem)?.position
return left < right
}
}
//MARK: - Overridden
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
let element = elements[currentItemIndex]
if segue.identifier == DBItemSegueIdentifier {
let itemViewController = segue.destinationViewController as! DBItemViewController
itemViewController.prepareWithElement(element)
}
}
//MARK: - UITableViewDataSource
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 0 //when I change to elements.count, deinit is not called
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier(DBItemCellIdentifier, forIndexPath: indexPath) as! DBItemTableViewCell
let element = elements[indexPath.row]
if let item = element as? DBItem {
cell.configureCellWithItem(item)
} else if let set = element as? DBSet {
cell.configureCellWithSet(set)
}
cell.delegate = self
return cell
}
//MARK: - UITableViewDelegate
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
currentItemIndex = indexPath.row
performSegueWithIdentifier(DBItemSegueIdentifier, sender: tableView.cellForRowAtIndexPath(indexPath))
}
//MARK: - DBItemTableViewCellDelegate
func itemTableViewCell(cell: DBItemTableViewCell, willPresentSetGroupsViewControllerForSet set: DBSet) {
presentSetOrderControllerWithOrder(DBSetOrder(set: set))
}
func itemTableViewCell(cell: DBItemTableViewCell, willPresentItemMealSizesViewControllerForItem item: DBItem) {
presentItemOrderControllerWithOrder(DBItemOrder(item: item))
}
}
Why my deinit is not called. I will offer 100 bounty once I will be able to do this, and award to that one, who help me solve this problem... I will offer a bounty even after solving the problem.
VERY IMPORTANT INFO:
this code calls deinit. IT IS WORKING. Because number of rows is 0. But I need to have there elements.count. When I change to this, deinit is not called.
EDIT:
func itemsForCategory(category: DBCategory, completionBlock: DBErrorHandler) {
let query = "locations/" + category.menu.location.identifier + "/categories/" + category.identifier
GET(query, parameters: nil, success: { operation, response in
if let error = NSError(response: response) {
completionBlock(error)
} else {
self.coreDataAssistant.parseAndSaveItemsToPersistentStore(response as? NSDictionary, completionBlock: { error in
completionBlock(error)
})
}
}) { operation, error in
let responseError = NSError(response: operation.responseObject)
completionBlock(responseError ?? error)
}
}

Answer 1

You are assigning self as your table view cell's delegate:
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier(DBItemCellIdentifier, forIndexPath: indexPath) as! DBItemTableViewCell
let element = elements[indexPath.row]
if let item = element as? DBItem {
cell.configureCellWithItem(item)
} else if let set = element as? DBSet {
cell.configureCellWithSet(set)
}
// HERE
cell.delegate = self
return cell
}
The cell's delegate property is defined as follows:
var delegate: DBItemTableViewCellDelegate?
This creates a strong reference between the cell and the delegate (your view controller). The cell is also retained by the table view. This creates a retain cycle.
You will need to change the definition of the delegate property to be weak:
weak var delegate: DBItemTableViewCellDelegate?
Edit based on comment:
Your DBItemTableViewCellDelegate definition will need to be defined as a class-only protocol
protocol DBItemTableViewCellDelegate: class {
...
}