+/- quantity of products in Cart View Controller with buttons each on a TableViewCell, which gets default quantity as integer from an array

问题

i am developing an app that you could add items to the Cart from MenuVC, then you can go to CartVC to view what is on your cart and increase or decrease quantity of items to be ordered. I cant make quantity label to change, don't know if thats because i get quantity from an array? is it unmutable?

Thank you for your help

Here is my cell

import UIKit

class BasketCell: UITableViewCell {

@IBOutlet weak var quantityLabel: UILabel!
@IBOutlet weak var itemLabel: UILabel!
@IBOutlet weak var priceLabel: UILabel!

var buttonIncrease : ((UITableViewCell) -> Void)?
var buttonDecrease : ((UITableViewCell) -> Void)?

override func awakeFromNib() {
    super.awakeFromNib()
    // Initialization code
}

override func setSelected(_ selected: Bool, animated: Bool) {
    super.setSelected(selected, animated: animated)

    // Configure the view for the selected state
}


@IBAction func increaseQuantity(_ sender: Any) {
    buttonIncrease?(self)
}

@IBAction func decreaseQuantity(_ sender: Any) {
    buttonDecrease?(self)
}

here is my example 2d array which i append it from web service

var items = 
    [
        ["Cheeseburger","Pizza","Sprite","Redbull"],
        ["10 $","20 $","5 $","6 $"],
        [1,1,2,1,2]
    ]

and here is my cellForRowAt @CartVC

 func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView1.dequeueReusableCell(withIdentifier: "basketCell", for: indexPath) as! BasketCell

    cell.quantityLabel.text = String(items[2][indexPath.row] as! Int)

    cell.buttonIncrease = { (cell) in
        var quantity = self.items[2][indexPath.row] as! Int
        quantity += 1
        self.tableView1.reloadData()
    }
    cell.buttonDecrease = { (cell) in
        var quantity = self.items[2][indexPath.row] as! Int
        if quantity > 1 {
        quantity -= 1
        self.tableView1.reloadData()
        }
    }

    cell.itemLabel.text = items[0][indexPath.row] as? String
    cell.priceLabel.text = items[1][indexPath.row] as? String

    return cell
}

回答1:

is it unmutable?

When you declare new variable by downcasting some element from array of Any objects, you get copy of this element which has no reference to element from array.

For your case would be better if you have your custom model

struct Item: Codable { // if you get this data from web service, you can use `JSONDecoder` to decode `Data` to `Item`/`[Item]`
    var title: String
    var price: String // better: `var price: Int` and then when you need to get text just add `" $"`
    var quantity: Int
}

then you can have your items array as array of Item objects

var items = [Item(title: "Cheeseburger", price: "10 $", quantity: 1), ...]

now you can get certain item from items in cellForRowAt as element from items with index equal to indexPath.row

let item = items[indexPath.row]
cell.quantityLabel.text = String(item.quantity)

And when you need to change it's amount property

self.items[indexPath.row].quantity += 1

来源：https://stackoverflow.com/questions/53996781/quantity-of-products-in-cart-view-controller-with-buttons-each-on-a-tablevie

标签

swift

xcode

uitableview

tableview