ios - How to add a button with click event on UITableViewCell in Swift?

Question

In my main page, I created a xib file for UITableViewCell. I'm loading the cell from that xib file and its working fine.

Inside of the cell I have some labels and buttons. I'm aiming to change the label by clicking to the button on the cell.

My Code likes below

import UIKit


class SepetCell: UITableViewCell{

    @IBOutlet var barcode: UILabel!
    @IBOutlet var name: UILabel!
    @IBOutlet var fav: UIButton!
    @IBOutlet var strep: UIStepper!
    @IBOutlet var times: UILabel!



    @IBAction func favoriteClicked(sender: UIButton) {
        println(sender.tag)
        println(times.text)

        SepetViewController().favorite(sender.tag)



    }
    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
    }
}

This is my xib files behind codes as .swift.

The codes in the main page likes below:

  import UIKit
import CoreData

class SepetViewController: UIViewController, UITextFieldDelegate, UITableViewDataSource, UITableViewDelegate {

  @
  IBOutlet
  var sepetTable: UITableView!
    var barcodes: [CART] = []

  let managedObjectContext = (UIApplication.sharedApplication().delegate as!AppDelegate).managedObjectContext

  override func viewWillAppear(animated: Bool) {
    if let moc = self.managedObjectContext {


      var nib = UINib(nibName: "SepetTableCell", bundle: nil)
      self.sepetTable.registerNib(nib, forCellReuseIdentifier: "productCell")
    }
    fetchLog()
    sepetTable.reloadData()
  }

  func fetchLog() {

    if let moc = self.managedObjectContext {
      barcodes = CART.getElements(moc);
    }
  }



  func tableView(tableView: UITableView, numberOfRowsInSection section: Int) - > Int {
    return self.barcodes.count
  }

  func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) - > UITableViewCell {


    let cell = tableView.dequeueReusableCellWithIdentifier("productCell") as ? SepetCell


    if cell == nil {
      println("cell nil")

    }



    let product: CART
    product = barcodes[indexPath.row]



    cell!.barcode ? .text = product.barcode
    cell!.name ? .text = product.name
    cell!.fav.tag = indexPath.row

    return cell!
  }

  func favorite(tag: Int) {



  }
}

When i clicked fav button inside of the Cell. I wanted to change times label text to anything for example.

When I clicked to the fav button, the event will gone to the SepetCell.swift favoriteClicked(sender: UIButton) function.

So if i try to call: SepetViewController().favorite(sender.tag)

It will go inside of the

func favorite(tag: Int) {

      sepetTable.reloadData()

    }

but sepetTable is nil when it is gone there. I think it is because of when I call this SepetViewController().favorite(sender.tag) function. It firstly creates SepetViewController class. So because of object is not setted it is getting null.

How can I reach that sepetTable or what is the best way to solve this issue.

Thanks.

Answer 1

Popular patterns for solving this problem are closures and delegates. If you want to use closures, you would do something like this:

final class MyCell: UITableViewCell {
    var actionBlock: (() -> Void)? = nil

then

    @IBAction func didTapButton(sender: UIButton) {
        actionBlock?()
    }

then in your tableview delegate:

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) - > UITableViewCell {

    let cell = tableView.dequeueReusableCellWithIdentifier("MyCellIdentifier") as? MyCell
    cell?.actionBlock = {
       //Do whatever you want to do when the button is tapped here
    }

---

A popular alternative is to use the delegate pattern:

    protocol MyCellDelegate: class {
        func didTapButtonInCell(_ cell: MyCell)
    }

    final class MyCell: UITableViewCell {
        weak var delegate: MyCellDelegate?

then

    @IBAction func didTapButton(sender: UIButton) {
        delegate?.didTapButtonInCell(self)
    }

.. Now in your view controller:

then in your tableview delegate:

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) - > UITableViewCell {

    let cell = tableView.dequeueReusableCellWithIdentifier("MyCellIdentifier") as? MyCell
    cell?.delegate = self

And add conformance to the protocol like this:

extension MyViewController: MyCellDelegate {
    didTapButtonInCell(_ cell: MyCell) {
       //Do whatever you want to do when the button is tapped here
    }
}

Hope this helps!