快速更新表格视图单元格

Question

BACKGROUND

I have a simple bill splitting app that allows the users to assign a meal item to multiple people or users. When the meal is assigned to multiple people, the price is divided accordingly. The meal (which contains an item name and a price are the rows and the users are the sections.

When I delete a row, I want to delete the row, and update or alter certain other values (I basically want to reassign the price to one less person when an item is deleted from a user). My data model is a multidimensional array . Here it is:

 struct UserModel {
    var name: String
    var itemModels = [ItemModel]()

    init(name: String, itemModels: [ItemModel]? = nil) {
        self.name = name
        if let itemModels = itemModels {
            self.itemModels = itemModels
        }
    }
}

    struct ItemModel {
    var itemName: String
    var price: Double

    init(itemName: String, price: Double) {
        self.itemName = itemName
        self.price = price
    }
}
    class Data {
    static var userModels = [UserModel]()
    static var itemModels = [ItemModel]()
}

For example, in trailingSwipeActionsConfigurationForRowAt

func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
    let delete = UIContextualAction(style: .destructive, title: "Delete") { (contextualAction, view, actionPerformed: @escaping (Bool) -> ()) in

        let user = Data.userModels[indexPath.section].name
        let item = Data.userModels[indexPath.section].itemModels[indexPath.row].itemName
        let price = Data.userModels[indexPath.section].itemModels[indexPath.row].price


        ItemModelFunctions.removeFromUser(from: indexPath.section, remove: indexPath.row)

        var duplicate = Data.userModels.filter({$0.itemModels.contains(where: {$0.itemName == item})}).filter({$0.name != user}) 

        for i in 0..<duplicate.count {
            ???
        }
        tableView.reloadData()
        actionPerformed(true)
    }
    return UISwipeActionsConfiguration(actions: [delete])
}

The variable var duplicate returns an array of the other users who have the same item at the indexPath.row , but not the user( indexPath.section ) who has the item. I know it sounds really confusing, but I can provide more code or print statements if needed.

Also in the for loop , I want to do something like this:

for i in 0..<duplicate.count {
    let oldPrice = duplicate[i].price
    let newPrice = oldPrice * duplicate.count
    duplicate[i].price = newPrice
}

But I can't access the price. I believe need an indexPath.section and indexPath.row .

If you made it this far, thank you for taking the time. I feel like I need a nested loop, but I'm not sure how exactly to implement that. If there are any other easier ways to achieve this I'm open to any suggestions.

Thank you so much!

EDIT: The marked answer worked! In case anyone else was having a similar issue this is what my final code looks like in the trailingSwipeActionsConfigurationForRowAt :

func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
    let delete = UIContextualAction(style: .destructive, title: "Delete") { (contextualAction, view, actionPerformed: @escaping (Bool) -> ()) in

        let item = Data.userModels[indexPath.section].itemModels[indexPath.row]
        ItemModelFunctions.removeFromUser(from: indexPath.section, remove: indexPath.row)

        let duplicate = Data.userModels.filter({$0.itemModels.contains(item)})

        for i in 0..<Data.userModels.count {
            if let idx = Data.userModels[i].itemModels.firstIndex(of: item) {
                let oldPrice = Data.userModels[i].itemModels[idx].price

                let newPrice = oldPrice * Double(duplicate.count+1)

                Data.userModels[i].itemModels[idx].price = newPrice / Double(duplicate.count)
            }
        }
        tableView.reloadData()
        actionPerformed(true)
    }
    return UISwipeActionsConfiguration(actions: [delete])
}

Answer 1

Perhaps you can try this. Best of luck, please comment if it doesn't work. I am new to Swift :)

let actualItem = Data.userModels[indexPath.section].itemModels[indexPath.row]

for i in 0..<duplicate.count {
  if let idx = duplicate[i].itemModels.firstIndex(of: actualItem) {
     let oldPrice = duplicate[i].itemModels[idx].price
     duplicate[i].itemModels[idx].price = oldPrice * duplicate.count
  }
}