Save an array of multiple selected UITableViewCell values

Question

I'm stuck with a very specific problem while using a Table View (XCode 9, Swift 4). What I want to do is, make an array named foodDetailInfoArray with text values of the foodName label in the table cells which have been selected manually by the user. Currently, while the .setSelected method works for changing the UI for a cell as I want, it isn't helping me record the foodName.text value properly. The problem is that the text values get recorded even while scrolling the table view and the array values get replaced as well. Below is the code and a sample of the printed output.

var foodDetailInfoArray: [String] = []

@IBOutlet var unselectedCell: UIView!
@IBOutlet var foodName: UILabel!
@IBOutlet var carbonValue: UILabel!

override func setSelected(_ selected: Bool, animated: Bool) {
    super.setSelected(selected, animated: animated)
    // Configure the view for the selected state
    if selected == true {
        self.unselectedCell.backgroundColor = UIColor.init(red: 4/255, green: 206/255, blue: 132/255, alpha: 1)
        self.foodName.textColor = UIColor.white
        self.carbonValue.textColor = UIColor.white
        foodDetailInfoArray.append(foodName.text!)
    } else {
        self.unselectedCell.backgroundColor = UIColor.clear
        self.foodName.textColor = UIColor.black
        self.carbonValue.textColor = UIColor.black
    }

    print(foodDetailInfoArray)
}

The print statement gives me this sort of result: (This is when the cells are not even selected and I'm just scrolling the table view.)

["pepper"]
["pasta"]
["pasta", "pepper"]
["pepper"]
["pepper", "pasta"]
["stir-fry"]
["stir-fry", "stir-fry"]
["vegetable"]
["vegetable", "vegetable"]

Whereas, what I ideally want would be (in the order of clicking the cell that contains given foodName):

["pasta"]
["pasta", "pepper"]
["pasta", "pepper", "tomato"]
["pasta", "pepper", "tomato", "stir-fry"]

and if a certain cell is deselected then the name has to be dropped, ie if tomato is deselected, then array would be

["pasta", "pepper", "stir-fry"]

... and so on

PS: I'm not a programmer by profession and altogether self taught recently, so please let me know if the question is unclear in any way.

Answer 1

I would try the delegate method didSelectRowAtIndexPath for tableViews. Have your view controller adopt the UITableViewDelegate protocol and implement the following.

Suppose you have a foods array, and a foodsSelected array that's initially empty.

let foods:[String] = ["Apples","Avocado","Bananas"]
var foodsSelected:[String] = []

Now whenever a cell is selected, this delegate method is called and add or remove the selected food from the foodsSelected array.

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    //Check if the selected food is in the foodsSelect array
    if(!foodsSelected.contains(foods[indexPath.row])){
        //If it's not, append it to the array
        foodsSelected.append(foods[indexPath.row])
    }else{
        //If it is, remove it from the array. 
        //Note there are many ways to remove an element from an array; I decided to use filter. 
        foodsSelected = foodsSelected.filter({$0 != foods[indexPath.row]})
    }
    print(foodsSelected)
}

Here is the output when I select these items in order: Apples, Avocado,Bananas,Avocado

["Apples"]
["Apples", "Avocado"]
["Apples", "Avocado", "Bananas"]
["Apples", "Bananas"]

Answer 2

I would handle the selection and deselection of the cell via the view controller, so you can also use your foodDetailInfoArray better. With the help of this answer you could do it like that way:

import UIKit

class ViewController: UITableViewController {

    // example data
    let names = [ "pepper", "pasta", "stir-fry", "vegetable"]

    var foodDetailInfoArray: [String] = []

    override func viewDidLoad() {
        super.viewDidLoad()

        // allow multiselection
        tableView.allowsMultipleSelection = true
    }


    // MARK: UITableViewDataSource

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 4
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = UITableViewCell(style: .default, reuseIdentifier: "cell")
        cell.textLabel?.text = names[indexPath.row]
        // Don't show highlighted state
        cell.selectionStyle = .none

        return cell
    }

    // MARK: UITableViewDelegate

    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        // also do your UI changing for the cell here for selecting

        // Add your food detail to the array
        foodDetailInfoArray.append(names[indexPath.row])
    }

    override func tableView(_ tableView: UITableView, didDeselectRowAt indexPath: IndexPath) {
        // also do your UI changing for the cell here for deselecting

        // Remove your food detail from the array if it exists
        if let index = foodDetailInfoArray.index(of: names[indexPath.row]) {
            foodDetailInfoArray.remove(at: index)
        }
    }

}

Result