Auto switching between UITextFields with Swift

Question

I have 4 UITextFields in one UIView like this:

each UITextField limited to 4 characters. i want implement a auto switching between UITextFields with count characters of each UITextField.

i use shouldChangeCharactersIn for limitation characters:

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        let maxLength = 4
        var newString = String()
        let currentString: NSString = textField.text! as NSString
        newString = currentString.replacingCharacters(in: range, with: string)

        return newString.length <= maxLength
    }

and this is my switching implement:

func textFieldDidChange(_ textField: UITextField){

    let text = textField.text

    if text?.utf16.count == 4 {
        switch textField {
        case firstPartTextField:
            secondPartTextField.becomeFirstResponder()
        case secondPartTextField:
            thirdPartTextField.becomeFirstResponder()
        case thirdPartTextField:
            fourthPartTextField.becomeFirstResponder()
        default:
            break
        }
    }
}

my problem is switch to previous UITextField in deleting texts, i can not detect backSpace event when UITextField is empty.

(1) Not all credit cards are 16-digit long (2) Maybe you could use existing libraries instead of inventing your own. — kennytm
– kennytm, Commented Jan 28, 2017 at 17:43
Try this answer, this worked for me stackoverflow.com/a/39483754/6245319 — Mohsen Hosseinpour
– Mohsen Hosseinpour, Commented Jan 28, 2017 at 19:55
i personally don't like to input a number into 4 seperate textfields :( — muescha
– muescha, Commented Jan 29, 2017 at 3:48
for example pasting creditcard from my 1Password is not possible with this 4 Textfields :( — muescha
– muescha, Commented Jan 29, 2017 at 3:49

rptwsthi · Accepted Answer · 2017-06-19 06:42:34Z

1

Add target for textField in viewDidLoad()

firstTxt.addTarget(self, action: #selector(textFieldDidChange(textField:)), for: UIControlEvents.editingChanged)
    secTxt.addTarget(self, action: #selector(textFieldDidChange(textField:)), for: UIControlEvents.editingChanged)
    thirdTxt.addTarget(self, action: #selector(textFieldDidChange(textField:)), for: UIControlEvents.editingChanged)
    fourTXt.addTarget(self, action: #selector(textFieldDidChange(textField:)), for: UIControlEvents.editingChanged)

Than create selector method

func textFieldDidChange(textField: UITextField){

    let text = textField.text

    if text?.utf16.count == 1{
        switch textField{
        case firstTxt:
            secTxt.becomeFirstResponder()
        case secTxt:
            thirdTxt.becomeFirstResponder()
        case thirdTxt:
            fourTXt.becomeFirstResponder()
        case fourTXt:
            fourTXt.resignFirstResponder()
        default:
            break
        }
    }else{

    }
}

edited Jun 19, 2017 at 6:42

rptwsthi

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answered Jun 19, 2017 at 6:37

AbhiRaz

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2 Comments

thewaywewere Over a year ago

While this code may answer the question, providing additional context regarding how and/or why it solves the problem would improve the answer's long-term value.

AbhiRaz Over a year ago

As above each UITextField had a selector which call by self and when the text will change it will count the character and when it comes true to the condition it will change to next UITextField

CoderSulemani · Accepted Answer · 2017-11-30 07:22:32Z

Make an outlet collection of all your textfields and configure them like so:

OutletCollection:

@IBOutlet var textfields: [UITextField]!

Add this in viewDidLoad:

for (i, tf) in textfields.enumerated() {
    tf.layer.cornerRadius = 5
    tf.clipsToBounds = true
    tf.tag = i
    tf.delegate = self
}

In the target function, you'll restrict the count in this manner:

func textFieldDidChange(textField: UITextField) {
       let text = textField.text!
       if text.utf16.count >= 4 {
           if textField.tag < 4 {
               codeTextfields[textField.tag + 1].becomeFirstResponder()
           }
           else {
               textField.resignFirstResponder()
           }
       }
}

This will the change in one of your delegate methods:

func textFieldDidBeginEditing(_ textField: UITextField) {
        textField.text = ""
}

Refined version of the following answer: How to move cursor from one text field to another automatically in swift ios programmatically?

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