How to remove row in UITableViewController presented as popover - ios

Question

I have a custom UITableViewController that I present as a popover in my app. In some of the cells there is a delete button (trash can) to remove that item. Everything works as it should except that I the UI is not update when pressing the delete button. That is, the data is cleared and I call self.tableView.reloadData(), but the cell remains visible in the UI. (Pressing the delete button again makes the app crash in my C++ code because of an assert). I have no storyboard or xib as I do not need it. I only want this to be in code.
What am I missing? It might be something simple, but I cannot fathom why. I have tried:
Separate data source implementation.
Calling reloadData() both sync and async.
Setting delegate to self.
Various other hacks.
Here is the UITableViewController implementation:
import Foundation
class IngredientInfoPopoverViewController : UITableViewController
{
var slViewController: ShoppingListViewController?;
var ingredientName: String = "Ingrediens";
#IBOutlet var uniqueIngredients: [Ingredient] = []; // Unique per *recipe* so that we can list all the recipes for the ingredients
var clickedCellIndexPath: IndexPath? = nil;
enum SECTIONS : Int
{
case HEADER = 0;
case RECIPE = 1;
}
static let ROW_HEIGHT = 44;
override func viewDidLoad()
{
super.viewDidLoad();
tableView.register(UINib(nibName: "OpenIngredientInfoCell", bundle: nil), forCellReuseIdentifier: "OpenIngredientInfoCell");
tableView.register(UINib(nibName: "OpenRecipeCell", bundle: nil), forCellReuseIdentifier: "OpenRecipeCell");
tableView.separatorStyle = .singleLine;
tableView.bounces = false; // "Static" table view
updateSize();
}
func updateSize()
{
let totalCount = min(uniqueIngredients.count + 1, 6); // + 1: header row. min: Allow max 5 recipes in list (enables scrolling)
self.preferredContentSize = CGSize(width: 300, height: totalCount * IngredientInfoPopoverViewController.ROW_HEIGHT);
}
func setup(slvc: ShoppingListViewController?, ingredients: [Ingredient], clickedCellIndexPath: IndexPath)
{
self.slViewController = slvc;
self.clickedCellIndexPath = clickedCellIndexPath;
if (ingredients.count > 0)
{
let first = ingredients[0];
for i in ingredients
{
assert(i.getId() == first.getId());
}
ingredientName = first.getName();
var uniqueRecipeNames: Set<String> = [];
for i in ingredients
{
uniqueRecipeNames.insert(i.getRecipeName());
}
let sorted = uniqueRecipeNames.sorted();
uniqueIngredients.removeAll();
for s in sorted
{
for i in ingredients
{
if (i.getRecipeName() == s)
{
uniqueIngredients.append(i);
break;
}
}
}
}
}
override func numberOfSections(in tableView: UITableView) -> Int
{
return 2;
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int
{
switch section
{
case SECTIONS.HEADER.rawValue:
return 1;
case SECTIONS.RECIPE.rawValue:
return uniqueIngredients.count;
default:
assert(false);
return 0;
}
}
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath)
{
switch (indexPath.section)
{
case SECTIONS.HEADER.rawValue:
assert(indexPath.row == 0);
if (uniqueIngredients.count > 0)
{
let ingredient = uniqueIngredients[0]; // All are the same ingredient
self.dismiss(animated: true, completion: nil);
slViewController?.onIngredientInfoButtonClicked(ingredient);
}
break;
case SECTIONS.RECIPE.rawValue:
if (indexPath.row < uniqueIngredients.count)
{
let ingredient = uniqueIngredients[indexPath.row];
self.dismiss(animated: true, completion: nil);
slViewController?.onRecipeInfoButtonClicked(ingredient);
}
break;
default:
break;
}
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
{
let cell = UITableViewCell();
switch (indexPath.section)
{
case SECTIONS.HEADER.rawValue:
if (uniqueIngredients.count > 0)
{
let ingredient = uniqueIngredients[0];
let cell = tableView.dequeueReusableCell(withIdentifier: "OpenIngredientInfoCell", for: indexPath) as! OpenIngredientInfoCell;
cell.setup(ingredient);
}
break;
case SECTIONS.RECIPE.rawValue:
if (indexPath.row < uniqueIngredients.count)
{
cell.selectionStyle = .none; // Without this the cell contents become gray and disappear when long pressing! FML
let ingredient = uniqueIngredients[indexPath.row];
let cell = tableView.dequeueReusableCell(withIdentifier: "OpenRecipeCell", for: indexPath) as! OpenRecipeCell;
cell.setup(self, ingredient, clickedCellIndexPath);
}
break;
default:
break;
}
return cell;
}
override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat
{
return CGFloat(IngredientInfoPopoverViewController.ROW_HEIGHT);
}
func ingredientRemoved(_ ingredient: Ingredient)
{
for i in 0..<uniqueIngredients.count
{
if (uniqueIngredients[i].getRecipeId() == ingredient.getRecipeId())
{
uniqueIngredients.remove(at: i);
// let indexPath = IndexPath(row: i, section: SECTIONS.RECIPE.rawValue);
// self.tableView.deleteRows(at: [indexPath], with: .fade);
DispatchQueue.main.async {
self.tableView.reloadData();
}
break;
}
}
if (uniqueIngredients.count == 0)
{
self.dismiss(animated: true, completion: nil);
}
else
{
DispatchQueue.main.async {
self.tableView.reloadData();
}
}
}
}
Here is how I present the IngredientInfoPopoverViewController:
#objc func ingredientInfoClicked(_ sender: UITapGestureRecognizer)
{
let tapLocation = sender.location(in: self.tableView)
let indexPath = self.tableView.indexPathForRow(at: tapLocation)!
let ingredients = CppInterface.shoppingList.getIngredients(UInt(indexPath.section), position: UInt(indexPath.row));
let controller = IngredientInfoPopoverViewController();
controller.setup(slvc: self, ingredients: ingredients!, clickedCellIndexPath: indexPath);
controller.modalPresentationStyle = .popover;
controller.popoverPresentationController!.delegate = self;
self.present(controller, animated: true, completion: {
self.tableView.reloadData();
});
}
Here is how the view controller looks when presented. If I click the trash can on one of the items, the data is cleared, but the cell is not removed from the UI, which is what I am trying to achieve.

Answer 1

I'm actually surprised your tableView shows any data at all. Because you declare cell as a let in cellForRowAt when you do let cell = UITableViewCell();, that makes it immutable, and the first cell (outside of the switch) is the one that should technically get returned. Hence why no data should be displaying. And probably also the reason why your tableView is not updating correctly.
Anyway, you should only declare cell when you're dequeueing it, and you should as much as possible, avoid force-unwrapping of a variable.
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if indexPath.section == SECTIONS.HEADER.rawValue, let cell = tableView.dequeueReusableCell(withIdentifier: "OpenIngredientInfoCell", for: indexPath) as? OpenIngredientInfoCell {
// not sure this check is necessary, but I'm adding it because it was in your original code
guard uniqueIngredients.count > 0 else { return UITableViewCell() }
let ingredient = uniqueIngredients[0]
cell.setup(ingredient)
return cell
} else if indexPath.section == SECTIONS.RECIPE.rawValue, let cell = tableView.dequeueReusableCell(withIdentifier: "OpenRecipeCell", for: indexPath) as? OpenRecipeCell {
// it shouldn't be possible for the indexPath to ever be greater than the dataSource items count, but I'll keep the check
guard indexPath.row < uniqueIngredients.count else { return UITableViewCell() }
cell.selectionStyle = .none
let ingredient = uniqueIngredients[indexPath.row]
cell.setup(self, ingredient, clickedCellIndexPath)
return cell
}
return UITableViewCell()
}
I've removed the semi-colons as they're not necessary in Swift.
For specifying the table cells' reuse identifiers, using the class names would probably be better. So you would use "\(OpenRecipeCell.self)" instead of "OpenRecipeCell"

Answer 2

If you are using the defaulted way of editing a UITableView (either swiping or entering edit mode), then here's my delegate code that works fine:
func tableView(_ tableView: UITableView, moveRowAt sourceIndexPath: IndexPath, to destinationIndexPath: IndexPath) {
let movedStep = appState.recipe.steps[sourceIndexPath.row]
appState.recipe.steps.remove(at: sourceIndexPath.row)
appState.recipe.steps.insert(movedStep, at: destinationIndexPath.row)
}
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete {
appState.recipe.steps.remove(at: indexPath.row)
tblSteps.deleteRows(at: [indexPath], with: .automatic)
}
}
Notes:
I manually place this table view in edit mode through a UIBarButtonItem, and a cell can both be moved or deleted.
My data source is in my model, at appState.recipe.steps. The structure doesn't matter, just handling the array.
I set a Notification anytime this array is changed that triggers a reloadData() in this table view.
I don't see either of these delegate methods listed, so I'm posting this answer. If by chance it doesn't help you, I'll gladly delete this.