How to limit length of input of Textfield - Swift 2 - ios

Question

This code works perfectly, and I can't key in anything other than integers, even when I try to paste it in.
I'd like to add one more refinement, which is to limit the length of the input. Here's my code:
func initializeTextFields()
{
APTeams.delegate = self
APTeams.keyboardType = UIKeyboardType.NumberPad
APRounds.delegate = self
APRounds.keyboardType = UIKeyboardType.NumberPad
APBreakers.delegate = self
APBreakers.keyboardType = UIKeyboardType.NumberPad
}
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
// Find out what the text field will be after adding the current edit
let text = (textField.text! as NSString).stringByReplacingCharactersInRange(range, withString: string)
if text == "" {
return true
}
if let _ = Int(text) {
return true
}
else {
return false
}
}
What do I have to add to it to achieve this? The maximum input length for all the TextFields should be <= 4.
BTW, all code is in Swift 2. From problems I faced when trying to implement answers to questions I've asked before, I gather that some of the methods are different.

Answer 1

count(textField.text) is deprecated in SWIFT 2.0
public func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
if let textField = textField as? UITextField {
if (range.length + range.location > textField.text!.characters.count) {
return false;
}
let newLength = textField.text!.characters.count + string.characters.count - range.length;
switch(textField.tag) { //In case you want to handle multiple textfields
case Constants.TAG1:
return newLength <= 20;
case Constants.TAG2:
return newLength <= 30;
default:
return newLength <= 15;
}
}
return true;
}

Answer 2

Write the condition in textfield delegate method as:-
func textField(textField: UITextField!, shouldChangeCharactersInRange range: NSRange, replacementString string: String!) -> Bool {
if (count(textField.text) > 4 && range.length == 0)
{
return false // return NO to not change text
}
else
{
}
write all your code part in else part.

Answer 3

The delegate methods or an NSFormatter such as NSNumberFormatter.
The formatter is the most appropriate generally as it also provides localization support.

Answer 4

I know its bit too late but still I want share it too, I found a way which is much easier to set a limit character for an textfield in swift development.
Here is the code:-
import UIKit
private var maxLengths = [UITextField: Int]()
extension UITextField {
#IBInspectable var maxLength: Int {
get {
guard let length = maxLengths[self] else {
return Int.max
}
return length
}
set {
maxLengths[self] = newValue
addTarget(self, action: #selector(limitLength), for: .editingChanged)
}
}
#objc func limitLength(textField: UITextField) {
guard let prospectiveText = textField.text, prospectiveText.count > maxLength else {
return
}
let selection = selectedTextRange
let maxCharIndex = prospectiveText.index(prospectiveText.startIndex, offsetBy: maxLength)
#if swift(>=4.0)
text = String(prospectiveText[..<maxCharIndex])
#else
text = prospectiveText.substring(to: maxCharIndex)
#endif
selectedTextRange = selection
}
}
and just set the limit through the panel.
Image:

Answer 5

Just try this to limit the length of TF
Editing changed Action Outlet of TF
#IBAction func otpTF2EditingChnaged(_ sender: UITextField) {
if (sender.text?.count == 1) {
otpTF3.becomeFirstResponder()
}
checkMaxLength(textField: sender , maxLength: 1)
}
Function That will limit the length
private func checkMaxLength(textField: UITextField!, maxLength: Int) {
if (textField.text!.count > maxLength) {
textField.deleteBackward()
}
}