How to identify first and last rows of each section | Swift

Question

How can I identify the first and last rows of each section in a dynamic tableview and make a view inside the cell class hidden.

For each first cell in each section I need to hide the topView, for each last row of each section, I need to hide the bottomView.

For example I have the following Class:

class cell: UITableViewCell {
    @IBOutlet weak var topView: UIView!
    @IBOutlet weak var bottomView: UIView!
    
}

I have tried to identify the last row of each section by doing the following, but it simple does not hide the correct bottomView, except for in the last section. Is there a way to identify the rows correctly?

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    
    let cell = tableView.dequeueReusableCell(withIdentifier: "cell") as! cell
    
    let item = sections[indexPath.section].items[indexPath.row]
    structure = sections[indexPath.section].items
   
    
    let totalRow = tableView.numberOfRows(inSection: indexPath.section)
    
    if(indexPath.row == totalRow - 1)
    {
        cell.bottomView.isHidden = true
    }
    return cell
    
}

var sections = [mySections]()
var structure = [myStructure]()

Fetching Data:

private func fetchJSON() {
    
    guard let url = URL(string: "test.com")
    else { return }
    
    var request = URLRequest(url: url)
    request.httpMethod = "POST"
    request.httpBody = "id=\1".data(using: .utf8)
    

URLSession.shared.dataTask(with: request) { data, _, error in
guard let data = data else { return }
                
do {
  let decoder = JSONDecoder()
  self.structure.sort { $0. datestamp > $1.datestamp }
  let res = try decoder.decode([myStructure].self, from: data)
  let grouped = Dictionary(grouping: res, by: { $0. datestamp })
  let keys = grouped.keys.sorted()
self.sections = keys.map({mySections(date: $0, items: grouped[$0]!
                    
)})
  DispatchQueue.main.async {
  self.tableView.reloadData()
}
        }
        
        catch {
            print(error)
        }
    }.resume()
 }

Struct:

struct mySections {
    let date : String
    var items : [myStructure]
}


struct myStructure: Decodable {
    
    let recordid: Int
    let testname: Int
    let datestamp: String
}

Example of Data:

[
  { 
    "recordid": 1,
    "testname": "Jen",
    "datestamp": "2021-11-3"
  },
  {
    "recordid": 1,
    "testname": "Jake",
    "datestamp": "2021-11-2"
  }
]

Setting Up Sections:

 override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        let section = sections[section]
        return section.items.count
    }
    
  override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
        return sections[section].date
    }

Answer 1

When you are in your delegate creating cells, you are in the process of telling the table view what rows and sections it has. That means that the table view hasn't finished setting up sections so it's not the right time to call tableView.numberOfRows(inSection:).

You're already pulling your data out of the model... in this case it looks like your model has an array of sections and each section has an array of rows, so ask the model whether or not the cell your building is at the beginning or end of its section:

import UIKit
import SwiftUI
import PlaygroundSupport

class CustomCell : UITableViewCell {
    static let identifier = "CustomCell"
}

class DataSource : NSObject, UITableViewDataSource {
    let sections = [
        [
            "Cow",
            "Duck",
            "Chicken"
        ],

        [
            "Lion",
            "Zebra",
            "Oryx"
        ],
    ]

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

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

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let newCell = tableView.dequeueReusableCell(withIdentifier: CustomCell.identifier, for: indexPath)
        if let cell = newCell as? CustomCell {
            cell.textLabel?.text = sections[indexPath.section][indexPath.row]

            if indexPath.row == 0 {
                cell.textLabel?.backgroundColor = UIColor.yellow
            }

            if indexPath.row == sections[indexPath.section].count - 1 {
                cell.textLabel?.backgroundColor = UIColor.gray
            }
        }

        return newCell
    }
}

let tableView = UITableView(frame: CGRect(x: 0, y: 0, width: 320, height: 480))
tableView.register(CustomCell.self, forCellReuseIdentifier: CustomCell.identifier)
let dataSource = DataSource()
tableView.dataSource = dataSource

PlaygroundSupport.PlaygroundPage.current.liveView = tableView