How to update textLabel inside a tableview cell iOS Swift - ios

Question

I have created a table view programatically, below is the code, when I tried to update the label using a completion handler the value is not displayed in the table view cell.
Could someone please suggest me how I could update the textLabel in the languagesSpokenCell in my tableview ? I have spent several hours trying to get this resolved, but I am still unable to.
Here is the completion Handler that is called after the user selects the languages that he speaks.
func showLanguagesSpoken(_ languagesSpoken: [String]?){
        languagesSpokenString = (languagesSpoken?.joined(separator: ", "))!
        languagesSpokenCell.textLabel?.text = languagesSpokenString
       //*** In the below print statement the value is printed correctly but the text label is not updated in the cell. 
print("languagesSpokenCell.textLabel?.text: \(languagesSpokenCell.textLabel?.text)")
        self.tableView.reloadData()
    }
Here I am Programatically creating table view cells
// FOR TABLE VIEW - Tableview cells
    var tableView: UITableView  =   UITableView()
    var firstNameCell: UITableViewCell = UITableViewCell()
    var lastNameCell: UITableViewCell = UITableViewCell()
    var languagesSpokenCell: UITableViewCell = UITableViewCell()
    
    
    // FOR TABLE VIEW - Textfields
    var firstName: UITextField = UITextField()
    var lastName: UITextField = UITextField()
override func loadView() {
        super.loadView()
        
        // construct first name cell, section 0, row 0
        self.firstNameCell.backgroundColor = UIColor(red: 1.0, green: 1.0, blue: 1.0, alpha: 0.5)
        self.firstName = UITextField(frame: self.firstNameCell.contentView.bounds.insetBy(dx: 15, dy: 0))
        self.firstName.placeholder = "First Name"
        self.firstNameCell.addSubview(self.firstName)
        
        // construct last name cell, section 0, row 1
        self.lastNameCell.backgroundColor = UIColor(red: 1.0, green: 1.0, blue: 1.0, alpha: 0.5)
        self.lastName = UITextField(frame: self.lastNameCell.contentView.bounds.insetBy(dx: 15, dy: 0))
        self.lastName.placeholder = "Last Name"
        self.lastNameCell.addSubview(self.lastName)
        
self.languagesSpokenCell.textLabel?.text = "Languages Spoken"
        self.languagesSpokenCell.backgroundColor = UIColor(red: 1.0, green: 1.0, blue: 1.0, alpha: 0.5)
        self.languagesSpokenCell.accessoryType = UITableViewCellAccessoryType.disclosureIndicator
  
    }
Below are the Table view methods
func numberOfSections(in tableView: UITableView) -> Int {
return 2
}
// Return the number of rows for each section in your static table
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
switch(section) {
case 0: return 2 // section 0 has 2 rows
case 1: return 1 // section 1 has 1 row
default: fatalError("Unknown number of sections")
}
}
// Return the row for the corresponding section and row
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
switch(indexPath.section) {
case 0:
switch(indexPath.row) {
case 0: return self.firstNameCell // section 0, row 0 is the first name
case 1: return self.lastNameCell // section 0, row 1 is the last name
default: fatalError("Unknown row in section 0")
}
case 1:
switch(indexPath.row) {
case 0: return self.languagesSpokenCell
}
default: fatalError("Unknown section")
}
}
// Customize the section headings for each section
func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
switch(section) {
case 0: return "Profile"
case 1: return "Languages Spoken"
default: fatalError("Unknown section")
}
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let row = indexPath.row
let section = indexPath.section
let currentCell = tableView.cellForRow(at: indexPath) as! UITableViewCell
if section == 4 && row == 0 {
// The user has clicked on languages spoken cell
self.performSegue(withIdentifier: "showLanguageSelectionTVC", sender: self)
}
print("Printing celll text label: \(currentCell.textLabel!.text)")
}
Below are the constraints that I have set in the ViewDidLoad() method.
tableView = UITableView(frame: CGRect.zero, style: UITableViewStyle.grouped)
tableView.delegate = self
tableView.dataSource = self
tableView.register(UITableViewCell.self, forCellReuseIdentifier: "cell")
self.view.addSubview(self.tableView)
// Disabling automatic constraints
tableView.translatesAutoresizingMaskIntoConstraints = false
// Do any additional setup after loading the view.
let viewDict = [
"tableView" : tableView
]
// Setting Constraints for the table view
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|[tableView]|", options: [], metrics: nil, views: viewDict))
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|[tableView]|", options: [], metrics: nil, views: viewDict))

Answer 1

To update any cell in tableview you need to reload it. You can reload it per cell or or specific cells or whole tableview. Before reloading tableview make sure that you update your datasource.
In this showLanguagesSpoken method you are trying to change the text of cell without updating the tableView.
Also make sure you always changes the data in cellForRowAtIndexpath

Answer 2

Remove reloadData from following method.
func showLanguagesSpoken(_ languagesSpoken: [String]?){
languagesSpokenString = (languagesSpoken?.joined(separator: ", "))!
languagesSpokenCell.textLabel?.text = languagesSpokenString
//*** In the below print statement the value is printed correctly but the text label is not updated in the cell.
print("languagesSpokenCell.textLabel?.text: \(languagesSpokenCell.textLabel?.text)")
}

Answer 3

Label languagesSpokenCell.textLabel text update process should be on main thread.
func showLanguagesSpoken(_ languagesSpoken: [String]?) {
DispatchQueue.main.async {
languagesSpokenString = (languagesSpoken?.joined(separator: ", "))!
languagesSpokenCell.textLabel?.text = languagesSpokenString
print("languagesSpokenCell.textLabel?.text: \(languagesSpokenCell.textLabel?.text)")
}
}