How to do a live UITextField count while typing (Swift)?

Question

I would like to count the character when user keep typing in UITextField with swift.

Image of Field and Label:

Answer 1

To use the function below you need to implement the UITextFieldDelegate protocol on the text field you want to count. This gets called every time the UITextFields text changes:

Your class declaration should look something like this

class ViewController: UIViewController, UITextFieldDelegate

You should have an @IBOutlet similar to this

@IBOutlet var txtValue: UITextField

Set the UITextField s delegate to self.

override func viewDidLoad() {
    super.viewDidLoad()
    txtValue.delegate = self                
}

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
    let newLength = count(textField.text.utf16) + count(string.utf16) - range.length

    mylabel.text =  String(newLength) // Set value of the label
    // myCounter = newLength // Optional: Save this value
    // return newLength <= 25 // Optional: Set limits on input. 
    return true
}

Note that this function is called on all UITextFields so if you have several UITextFields you will need to add a logic to know witch one is calling this function.