How to arrange cells into sections with a custom header?

Question

How would I be able to arrange the cells by sections with a custom header

I have code set to arrange the cells in the CartVC by brand(placing the brand in the CartHeaderCell). When the data is passed from the HomeVC to the CartVC, I can't get my code arrange the cells into sections by brand from the code I created in the CartVC. (currently code passes data from HomeVC to CartVC without arranging the cells into sections)

How would I be arrange the sections by brand in the CartVC after data is passed into the Cart

Update:

Right Now the code in the CartViewController Extension arranges the cells into sections and passes the items into the cells by the brand, but scrambles all the cells into random sections or create a new section for the brand in the cells, and/or crashes the simulator when the CartBtn is pressed, or shows the same item/cell in multiple sections

extension HomeController: UITableViewDelegate, UITableViewDataSource {

    func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return itemSetup.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        guard let cell = tableView.dequeueReusableCell(withIdentifier: "HomeCell") as? HomeCell else { return UITableViewCell() }

        let item = itemSetup[indexPath.row]
        cell.configure(withItems: item)

        // passes data to the Cart Cells in the CartVC when ATC Btn is pressed in each HomeCell
        cell.addActionHandler = { (option: Int) in
            print("Option selected = \(option)")
            Tray.currentCart.cartItems.append(item)
            item.selectedOption = option
        }

        return cell
    }
}

---

import UIKit

class CartViewController: UIViewController {

    var items: Items!

    // arranges cells into sections
    var tray: [Tray] = []
    var sortedBrandsByName: [String] = []
    var sections: [[Tray]] = [[]]

    @IBOutlet weak var cartTableView: UITableView!

    override func viewDidLoad() {
        super.viewDidLoad()

        // arranges cells into sections
        let brandNames = tray.map { $0. titleBrandName }
        let uniqueBrandNames = Array(Set(brandNames))           
        let sortedBrandNames = uniqueBrandNames.sorted()
        let sections: [[Tray]] = sortedBrandNames.map { firstBrandNames in
            return tray
                .filter { $0. titleBrandName == firstBrandNames } 
                .sorted { $0.cart.brand < $1.cart.brand } // sort them
        }

        // Do any additional setup after loading the view.
        cartTableView.dataSource = self
        cartTableView.delegate = self

    }
}

---

extension CartViewController: UITableViewDataSource, UITableViewDelegate {

    func numberOfSections(in tableView: UITableView) -> Int {
        return Tray.currentCart.cartItems.count
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

        //allows data passed from the HomeVC populate the CartCells
        return Tray.currentCart.cartItems[section].count
    }

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

        // **Active code** that allows data passed from the HomeVC populate the CartCells
        let cart = Tray.currentCart.cartItems[indexPath.row]
        cell.configure(withItems: cart)

        return cell
    }

    func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        let cartHeader = tableView.dequeueReusableCell(withIdentifier: "CartHeaderCell") as! CartHeaderCell
        cartHeader.storeName.text = Tray.currentCart.cartItems[section].brand
        return cartHeader
    }

    func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
        return 45
     } 
}

---

class CartHeaderCell: UITableViewCell {

    @IBOutlet weak var brandName: UILabel!

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

class CartCell: UITableViewCell {

    @IBOutlet weak var lblMealName: UILabel!
    @IBOutlet weak var imageUrl: UIImageView!
    @IBOutlet weak var lblSubTotal: UILabel!
    @IBOutlet weak var lblQty: UILabel!

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

    // allows the data to be passed into the cart cells

    func configure(withItems items: Items) {
        imageUrl.sd_setImage(with: URL(string: items.imageUrl))
        lblQty.text = "\(items.count)"
        let formatter = NumberFormatter()
        formatter.maximumFractionDigits = 2
        formatter.numberStyle = .decimal
        if items.selectedOption == 1 {
            lblSubTotal.text = "$\(formatter.string(for: items.price1 * Float(items.count))!)"
            lblMealName.text = "\(items.name) ● \(items.weight1)"
        } else if items.selectedOption == 2 {
            lblSubTotal.text = "$\(formatter.string(for: items.price2 * Float(items.count))!)"
            lblMealName.text = "\(items.name) ● \(items.weight2)"
        } else if items.selectedOption == 3 {
            lblSubTotal.text = "$\(formatter.string(for: items.price3 * Float(items.count))!)"
            lblMealName.text = "\(items.name) ● \(items.weight3)"
        }
    } 
}

---

// allows the code that is passed to the CartVC when an item is passed from the HomeVC to the CartVC
class Tray {
    static let currentCart = Tray()
    var cartItems = [Items]()
    var cart: Items!
    var sectionTitle: String!
}

extension Tray {
    var titleBrandName: String {
        return String(self.cart.brand[self.cart.brand.startIndex]).uppercased()
    }
}

Answer 1

The issue is you're not actually saving the sorts you're doing. And even if you were.. you're looking at a different part of the code for your data in the UITableViewDataSource methods.

First issue: you're not actually saving your data. Make sure the function that creates CartViewController actually passes in the tray before viewDidLoad: !!

In this part:

import UIKit

class CartViewController: UIViewController {

    var items: Items!

    // arranges cells into sections
    var tray: [Tray] = []
    var sortedBrandsByName: [String] = []
    var sections: [[Tray]] = [[]]

    @IBOutlet weak var cartTableView: UITableView!

    override func viewDidLoad() {
        super.viewDidLoad()

        // arranges cells into sections
        let brandNames = tray.map { $0. titleBrandName }
        let uniqueBrandNames = Array(Set(brandNames))           
        let sortedBrandNames = uniqueBrandNames.sorted()
        let sections: [[Tray]] = sortedBrandNames.map { firstBrandNames in
            return tray
                .filter { $0. titleBrandName == firstBrandNames } 
                .sorted { $0.cart.brand < $1.cart.brand } // sort them
        }

        // Do any additional setup after loading the view.
        cartTableView.dataSource = self
        cartTableView.delegate = self

    }
}

your viewDidLoad creates LOCAL versions of sortedBrandNames and sections . Remove the lets and try this instead:

override func viewDidLoad() {
    super.viewDidLoad()

    // arranges cells into sections
    let brandNames = tray.map { $0. titleBrandName }
    let uniqueBrandNames = Array(Set(brandNames)) 

    // MY CHANGES ARE BELOW (remove let)      
    sortedBrandNames = uniqueBrandNames.sorted()
    sections: [[Tray]] = sortedBrandNames.map { firstBrandNames in
        return tray
            .filter { $0. titleBrandName == firstBrandNames } 
            .sorted { $0.cart.brand < $1.cart.brand } // sort them
    }

    // Do any additional setup after loading the view.
    cartTableView.dataSource = self
    cartTableView.delegate = self

}

General feedback.. you should use THESE to fill in your table view NOT the static Tray.currentTray . Having data held on a value that you can read/write from anywhere in the code base is REALLY BAD.

Secondly.. you're reading from a different data set on the UITableViewDataSource methods...

Say we did manage to save our sorted data now... when you do Tray.currentCart you actually are not looking at the data you just sorted (that would be self.sections ), at no point did you change the data in Tray.currentCart (again v bad don't make static stuff like this or singletons, its super easy to introduce bugs this way)

   func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

        //allows data passed from the HomeVC populate the CartCells
        return Tray.currentCart.cartItems[section].count
    }

Instead... try this:

extension CartViewController: UITableViewDataSource, UITableViewDelegate {

    func numberOfSections(in tableView: UITableView) -> Int {
        return self.sections.count
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return self.sections[section].count
    }

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

        let cart = self.sections[indexPath.section][indexPath.row]
        cell.configure(withItems: cart)

        return cell
    }

    func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        let cartHeader = tableView.dequeueReusableCell(withIdentifier: "CartHeaderCell") as! CartHeaderCell
        cartHeader.storeName.text = self.sections[section].brand
        return cartHeader
    }

    func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
        return 45
     } 
}

That way you're looking at the data you just sorted in viewDidLoad . (Note i'm assuming your sorting logic works correctly)