Limit UITextField input to numbers in Swift

Question

How can I get limit the user\'s TextField input to numbers in Swift?

Answer 1

In swift 4.1 and Xcode 10

Add UITextFieldDelegate to your class

class YourViewController: UIViewController, UITextFieldDelegate

Then write this code in your viewDidLoad()

yourTF.delegate = self

Write this textfield delegate function

//MARK - UITextField Delegates
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    //For numers
    if textField == yourTF {
        let allowedCharacters = CharacterSet(charactersIn:"0123456789")//Here change this characters based on your requirement
        let characterSet = CharacterSet(charactersIn: string)
        return allowedCharacters.isSuperset(of: characterSet)
    }
    return true
}