Swift unrecognized selector sent to instance error

I recently converted my project from Objective-C to Swift and in doing so I acquired this error whenever I click a button in the table view’s cell. I have multiple cells being filled with information from a mysql server. I have two buttons, a follow button and followed button, when one is clicked the other is supposed to show. I’ve been working on this for a while but I’ve been stuck on this error.

Error I’m getting when I click the button in the tableview

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  • CustomCellSwift[1425:372289] -[CustomCellSwift.ViewController followButtonClick:]: unrecognized selector sent to instance 0x100b13a40
    

    In CustomCell.swift

    class CustomCell: UITableViewCell {
    
    @IBOutlet weak var firstStatusLabel: UILabel!
    @IBOutlet weak var secondStatusLabel: UILabel!
    @IBOutlet weak var myImageView: UIImageView!
    @IBOutlet weak var followButton: UIButton!
    @IBOutlet weak var followedButton: UIButton!
    
    override func awakeFromNib() {
        super.awakeFromNib()
    
        self.followButton.isHidden = true
        self.followedButton.isHidden = true
    }
    
    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)
    }
    
    func populateCell(_ testObject: Test, isFollowed: Bool, indexPath: IndexPath, parentView: Any) {
    
        // Loading Background Color
        self.backgroundColor = UIColor.white
    
        // Loading Status Labels
        self.firstStatusLabel.text = testObject.testStatus1
        self.secondStatusLabel.text = testObject.testStatus2
        self.firstStatusLabel.isHidden = true
        self.secondStatusLabel.isHidden = true
    
        if isFollowed {
            self.followedButton.tag = indexPath.row
            self.followedButton.addTarget(parentView, action: Selector(("followedButtonClick")), for: .touchUpInside)
            self.followedButton.isHidden = false
            self.followButton.isHidden = true
    
            // Status Labels
            self.firstStatusLabel.isHidden = false
            self.secondStatusLabel.isHidden = false
    
        }
        else {
            self.followButton.tag = indexPath.row
            self.followButton.addTarget(parentView, action: Selector(("followButtonClick:")), for: .touchUpInside)
            self.followedButton.isHidden = true
            self.followButton.isHidden = false
    
            // Status Labels
            self.firstStatusLabel.isHidden = false // True when done testing
            self.secondStatusLabel.isHidden = false // True when done testing
    
        }
      }
    }
    

    ViewController.swift

    CellForRowAt indexPath

    public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    
        let CellIdentifier = "Cell"
        var cell = tableView.dequeueReusableCell(withIdentifier: CellIdentifier) as! CustomCell
    
        if cell != cell {
            cell = CustomCell(style: UITableViewCellStyle.default, reuseIdentifier: CellIdentifier)
        }
    
        // Coloring TableView
        myTableView.backgroundColor = UIColor.white
    
        // Configuring the cell
        var testObject: Test
    
        if !isFiltered {
            if indexPath.section == 0 {
                testObject = followedArray[indexPath.row] 
                cell.populateCell(testObject, isFollowed: true, indexPath: indexPath, parentView: self)
            }
            else if indexPath.section == 1 {
                testObject = testArray[indexPath.row] 
                cell.populateCell(testObject, isFollowed: false, indexPath: indexPath, parentView: self)
            }
        }
        else {
            testObject = filteredArray[indexPath.row] as! Test
            cell.populateCell(testObject, isFollowed: false, indexPath: indexPath, parentView: self)
        }
    
        return cell
    }
    

    Follow Button Code

    @IBAction func followButtonClick(sender: UIButton!) {
    
        // Adding row to tag
        let buttonPosition = (sender as AnyObject).convert(CGPoint.zero, to: self.myTableView)
        if let indexPath = self.myTableView.indexPathForRow(at: buttonPosition) {
    
            // Showing Status Labels
            let cell = self.myTableView.cellForRow(at: indexPath) as! CustomCell
            cell.firstStatusLabel.isHidden = false
            cell.secondStatusLabel.isHidden = false
    
            // Change Follow to Following
            (sender as UIButton).setImage(UIImage(named: "follow.png")!, for: .normal)
            cell.followButton.isHidden = true
            cell.followedButton.isHidden = false
            self.myTableView.beginUpdates()
    
            // ----- Inserting Cell to Section 0 -----
            followedArray.insert(testArray[indexPath.row], at: 0)
            myTableView.insertRows(at: [IndexPath(row: 0, section: 0)], with: .fade)
    
            // ----- Removing Cell from Section 1 -----
            testArray.remove(at: indexPath.row)
            let rowToRemove = indexPath.row
            self.myTableView.deleteRows(at: [IndexPath(row: rowToRemove, section: 1)], with: .fade)
    
            self.myTableView.endUpdates()
    
        }
    }
    

    Unfollow button code is the same as the follow button.

    I think the problem is in CustomCell.swift in the button selector((“”)) but the error is saying -[CustomCellSwift.ViewController followButtonClick:] which means in ViewController in the follow button code but I don’t know what to do anymore.

    3 Solutions Collect From Internet About “Swift unrecognized selector sent to instance error”

    Two changes for Swift 3:

    The selector should look like:

    #selector(ClassName.followButtonClick(_:))
    

    The function should have an underscore:

    @IBAction func followButtonClick(_ sender: UIButton!) { ...
    

    Notice that these two should be in the same class, otherwise, make sure you initialize the ClassName class.

    If you want the selector method(followButtonClick(_:)) to be in the UITableViewCell class. Remove @IBAction(I don’t think you need it there):

    func followButtonClick(_ sender: UIButton!) { ... 
    

    For swift 2.2 with Xcode8

    self.followedButton.addTarget(parentView, action: #selector(CustomCell.followButtonClick(_:)), forControlEvents: .TouchUpInside)
    

    For Swift3, you need to change the following:

    self.followedButton.addTarget(parentView, action: Selector(("followedButtonClick")), for: .touchUpInside)
    

    With:

    self.followedButton.addTarget(parentView, action: #selector(self.followButtonClick(_:)), forControlEvents: .touchUpInside)