backspace press not calling uitextfield's method

Question

I have four textField for purpose of OTP, and also set delegate to my viewcontroller in ViewDidLoad() method

I have also implement delegate method:

    func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
            if string.characters.count > 1 {
                return false
            } else {
                var tag = textField.tag
                if string.characters.count == 0 {
                    tag -= 1
                } else {
                    tag += 1
                }
                textField.text = string
                // Try to find next responder
                let nextResponder = textField.superview?.viewWithTag(tag) as UIResponder!
                nextResponder?.becomeFirstResponder()
            }
            return false
        }



func textFieldShouldReturn(textField: UITextField) -> Bool {
        print("BACKSPACE PRESSED")
        return true
    }

But both of this method not call when field is empty, actually i want clear text. Any Idea how to detect "backspace" is pressed when textfield is empty

if you find "BACKSPACE PRESSED" then what you want to develop functionality? — jignesh Vadadoriya, Nov 25 '16 at 09:37
**Return** does not mean backspace. **Return** means return carriage (return button pressed). — n00bProgrammer, Nov 25 '16 at 10:45
@jigneshVadadoriya i want previous textfield becomefirstresponder — SPatel, Nov 28 '16 at 04:45

score 1 · Answer 1 · answered Nov 25 '16 at 09:22

1

There is code to detect backspace

 const char * _char = [string cStringUsingEncoding:NSUTF8StringEncoding];
    int isBackSpace = strcmp(_char, "\b");

        if (isBackSpace == -8) {
            // Code there
           }

answered Nov 25 '16 at 09:22

Abdul Rehman

2,386
1
20
34

in "shouldChangeCharactersInRange" delegate method. – Abdul Rehman Nov 28 '16 at 06:32

score 1 · Answer 2 · answered Nov 28 '16 at 05:06

Directly Identify backspace is not proper logic. As per your requirement your text field become Blank then you want to previous text field become first responder then you need to write your code like this way

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {

    var txtAfterUpdate:NSString = textField.text! as NSString
    txtAfterUpdate = txtAfterUpdate.replacingCharacters(in: range, with: string) as NSString
    let updatedString = txtAfterUpdate as String

    if updatedString.characters.count == 0 {
        var tag = textField.tag
        tag -= 1
        let nextResponder = textField.superview?.viewWithTag(tag) as UIResponder!
        nextResponder?.becomeFirstResponder()

        return true
    } else{

        // rest of your functionality
    }

    return true
}

I hope it will help you.

This method not calling when textField is Empty – SPatel Nov 29 '16 at 12:14 — SPatel, Nov 29 '16 at 12:14

score 1 · Accepted Answer · answered Nov 29 '16 at 13:11

I get solution by overriding Following Method of UITextField.

class MYTextField: UITextField {
    override func deleteBackward() {
        super.deleteBackward()
        delegate?.textFieldShouldReturn!(self)
        print("_____________BACKSPACE_PRESSED_____________")
    }
}

backspace press not calling uitextfield's method

3 Answers3