UITextField, automatically move to next after 1 character

Question

Scenario: I have 4 UITextFields that only accept 1 character. Easy.

Problem: After I enter the 1 character, I want the next TextField to become active automatically with

Answer 1

The following is for Swift 5 and handles textfields as an array instead of individual fields.

import UIKit

class MyViewController: UIViewController, UITextFieldDelegate {

@IBOutlet var digitFields: [UITextField]!

override func viewDidLoad() {
    super.viewDidLoad()

    digitFields.forEach {
        configureDigitField($0)
    }
}

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    digitFields[0].becomeFirstResponder()
}

fileprivate func configureDigitField(_ digitField: UITextField) {
    digitField.delegate = (self as UITextFieldDelegate)
    digitField.addTarget(self, action: #selector(self.textFieldDidChange(textField:)), for: UIControl.Event.editingChanged)
}

// Move to next field in digit fields if the value is populated
@objc fileprivate func textFieldDidChange(textField: UITextField) {
    if textField.text?.count == 1 {
        let remaining = digitFields.filter { $0.text?.count == 0 }
        if remaining.count > 0 {
            remaining[0].becomeFirstResponder()
        } else {
            digitFields.forEach { $0.resignFirstResponder() }
        }
    }
}

Results in:

This is dependent on the textfields being grouped in an array. This can be achieved in interface builder by configuring the collection of fields in the Outlet configuration screen:

which can be reached from the view controller properties on the last tab item

Note that you need to manually add the

@IBOutlet var digitFields: [UITextField]!

to your view controller before you can add the text fields to it.

Summary of Code Behaviour

• The view controller needs to be a UITextFieldDelegate to allow it to receive textfield events.
• In the viewDidLoad function, each of the text fields in the array are initialised in the configureDigitField method
• In the viewWillAppear method the first field in the array is readied to handle input (i.e. the first entry will take place in it)
• The configureDigitalField function sets this view controller to receive events from the textfield (each of them as it is called for each textfield)
• It also sets up a selector to call the textFieldDidChange function on result of a textfield edit changed event
• textFieldDidChange method checks if the length of the text in the field is 1, and if so
• checks for the remaining text fields where there is no value entered
• takes the first remaining text field and sets it up to receive the next input
• if no remaining fields are empty, resigns its position as first responder, so any more keypresses will not occur in any of the digit fields