how to add an action on UITextField return key?

Ensure "self" subscribes to UITextFieldDelegate and initialise inputText with:

self.inputText.delegate = self;

Add the following method to "self":

- (BOOL)textFieldShouldReturn:(UITextField *)textField {    if (textField == self.inputText) {        [textField resignFirstResponder];        return NO;    }    return YES;}

Or in Swift:

func textFieldShouldReturn(_ textField: UITextField) -> Bool {    if textField == inputText {        textField.resignFirstResponder()        return false    }    return true}

With extension style in swift 3.0

First, set up delegate for your text field.

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

Then conform to UITextFieldDelegate in your view controller's extension

extension YourViewController: UITextFieldDelegate {    func textFieldShouldReturn(_ textField: UITextField) -> Bool {        if textField == inputText {            textField.resignFirstResponder()            return false        }        return true    }}

While the other answers work correctly, I prefer doing the following:

In viewDidLoad(), add

self.textField.addTarget(self, action: #selector(onReturn), for: UIControl.Event.editingDidEndOnExit)

and define the function

@IBAction func onReturn() {    self.textField.resignFirstResponder()    // do whatever you want...}