UITextField setting maximum character length in Swift

Question

How can I override this UITextField function so that it will have a limit on the maximum number of characters?

override func shouldChangeText(in range: UITex         


        

Answer 1

You can subclass UITextField and add a target for UIControlEvents editingChanged. Inside the selector method you can use collection method prefix to limit the characters added to your textfield text property as follow:

import UIKit
class LimitedLengthField: UITextField {
    var maxLength: Int = 10
    override func willMove(toSuperview newSuperview: UIView?) {
        addTarget(self, action: #selector(editingChanged), for: .editingChanged)
        editingChanged()
    }
    @objc func editingChanged() {
        text = String(text!.prefix(maxLength))
    }
}

---

You can add your custom text field programatically or using the interface builder:

import UIKit

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        let limitedLenghtField = LimitedLengthField(frame: CGRect(origin: CGPoint(x: 50, y: 50), size: CGSize(width: 200, height: 50)))
        limitedLenghtField.text = "123456789012345"
        view.addSubview(limitedLenghtField)
    }
}