UITextField text change event

Question

How can I detect any text changes in a textField? The delegate method shouldChangeCharactersInRange works for something, but it did not fulfill my need exactly. Since until it returns YES, the textField texts are not available to other observer methods.

e.g. in my code calculateAndUpdateTextFields did not get the updated text, the user has typed.

Is their any way to get something like textChanged Java event handler.

- (BOOL)textField:(UITextField *)textField 
            shouldChangeCharactersInRange:(NSRange)range 
            replacementString:(NSString *)string 
{
    if (textField.tag == kTextFieldTagSubtotal 
        || textField.tag == kTextFieldTagSubtotalDecimal
        || textField.tag == kTextFieldTagShipping
        || textField.tag == kTextFieldTagShippingDecimal) 
    {
        [self calculateAndUpdateTextFields];

    }

    return YES;
}

Answer 1

Swift 3 Version:

class SomeClass: UIViewController, UITextFieldDelegate { 

   @IBOutlet weak var aTextField: UITextField!


    override func viewDidLoad() {
        super.viewDidLoad()

        aTextField.delegate = self
        aTextField.addTarget(self, action: #selector(SignUpVC.textFieldDidChange), for: UIControlEvents.editingChanged)        
    }

   func textFieldDidChange(_ textField: UITextField) {

       //TEXT FIELD CHANGED..SECRET STUFF

   }

}

Don't forget to set the delegate.

Answer 2

Swift 4

func addNotificationObservers() {

    NotificationCenter.default.addObserver(self, selector: #selector(textFieldDidChangeAction(_:)), name: .UITextFieldTextDidChange, object: nil)

}

@objc func textFieldDidChangeAction(_ notification: NSNotification) {

    let textField = notification.object as! UITextField
    print(textField.text!)

}

Answer 3

Swift 3.1:

Selector: ClassName.MethodName

  cell.lblItem.addTarget(self, action: #selector(NewListScreen.fieldChanged(textfieldChange:)), for: .editingChanged)

  func fieldChanged(textfieldChange: UITextField){

    }

Answer 4

From proper way to do uitextfield text change call back:

I catch the characters sent to a UITextField control something like this:

// Add a "textFieldDidChange" notification method to the text field control.
[textField addTarget:self 
              action:@selector(textFieldDidChange:) 
    forControlEvents:UIControlEventEditingChanged];

Then in the textFieldDidChange: method you can examine the contents of the textField, and reload your table view as needed.

You could use that and put calculateAndUpdateTextFields as your selector.

Answer 5

XenElement's answer is spot on.

The above can be done in interface builder too by right-clicking on the UITextField and dragging the "Editing Changed" send event to your subclass unit.

Answer 6

We can easily configure that from Storyboard, CTRL drag the @IBAction and change event as following: