Switching to next UITextField when character limit is reached - swift

Question

I have three text fields to enter in a phone number. I am trying to set the character limit for each textfield to three characters and once this is reached switch to a new textfield.
I saw online to use this code to limit the characters:
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let currentCharacterCount = textField.text?.characters.count ?? 0
if (range.length + range.location > currentCharacterCount){
return false
}
let newLength = currentCharacterCount + string.characters.count - range.length
return newLength <= 25
}
and to use this to switch to typing on a new textfield:
.didbecomefirstresponder()
but I am not sure how to limit a text field to 3 characters and then switch to the next field.

Answer 1

This is my code, how I solve this:
The three textfields are:
#IBOutlet var txtField1: UITextField!
#IBOutlet var txtField2: UITextField!
#IBOutlet var txtField3: UITextField!
import UITextFieldDelegate in to your class and set the delegate to self for all the textfields.
And use this method to change focus.
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let currentCharacterCount = ((textField.text?.characters.count)! + string.characters.count) - 1
switch (textField, currentCharacterCount) {
case (self.txtField1, 3):
self.txtField2.becomeFirstResponder()
case (self.txtField2, 7):
self.txtField3.becomeFirstResponder()
default:
break
}
return true
}
Here I set character count 3 for the first textfield, and 7 for second textfield.

Answer 2

You could use the delegate method for UITextField shouldChangeCharactersInRange. You'd have to do a little setup work though. Here's an example that creates 3 textFields, conforms to the UITextFieldDelegate, and does something similar to what you're describing.
class ViewController: UIViewController, UITextFieldDelegate {
var max = 3
var fields:[UITextField] = []
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
// This is just an example to layout 3 text fields.
for i in 0 ..< 3 {
let field = UITextField()
view.addSubview(field)
field.delegate = self
field.borderStyle = .roundedRect
field.font = UIFont(name: "AvenirNext-Regular", size: 15.0)
field.textColor = UIColor.black
field.frame = CGRect(x: view.bounds.width/2 - 100, y: 100 + (150*CGFloat(i)), width: 200, height: 50)
fields.append(field)
}
}
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
// Make sure the field has non-nil text
if let text = textField.text {
// Check if the text length has reached max limit
if text.characters.count > (max-1) {
// Get index of field from fields array
if let index = fields.index(of: textField) {
// Make sure it's not the last field in the array else return false
if index < fields.count-1 {
// Make the next field in the array become first responder if it's text is non-nil and it's text's character count is less than desired max
if fields[index+1].text != nil && fields[index+1].text!.characters.count < (max-1) {
fields[index+1].becomeFirstResponder()
} else {
return false
}
} else {
return false
}
}
}
}
return true
}
}

Answer 3

I find Pierce's answers too complex and anas.p's answer doesn't work for me like it's supposed to. My Swift 5 solution:
override func viewDidLoad() {
textField1.addTarget(self, action: #selector(textFieldDidChange1), for:.editingChanged)
textField2.addTarget(self, action: #selector(textFieldDidChange2), for:.editingChanged)
}
#objc func textFieldDidChange1() {
// After 2 characters are typed, immediately jump to textField2
if (textField1.text?.count == 2) {
self.textField2.becomeFirstResponder()
}
}
#objc func textFieldDidChange2() {
if (textField2.text?.count == 2) {
self.textField3.becomeFirstResponder()
}
}