swift uitextfield only numbers keyboard lock programmatically
class ViewController: UIViewController, UITextFieldDelegate {
@IBOutlet weak var textField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
// you can set the following two properties for the text field in Interface Builder, if you'd prefer
textField.delegate = self
textField.keyboardType = .numberPad
}
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let invalidCharacters = CharacterSet(charactersIn: "0123456789").inverted
return string.rangeOfCharacter(from: invalidCharacters) == nil
}
// or, alternatively:
//
// func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
// return string.range(of: "^\\d*$", options: .regularExpression) != nil
// }
}