Prevent special characters in UITextField - swift

Question

How can I prevent the user from entering special characters in UITextField?

Answer 1

I solved the problem using this code:
let validString = NSCharacterSet(charactersInString: " !##$%^&*()_+{}[]|\"<>,.~`/:;?-=\\¥'£•¢")
// restrict special char in test field
if (textField == self.txt_firstName || textField == self.txt_lastName)
{
if let range = string.rangeOfCharacterFromSet(validString)
{
print(range)
return false
}
else
{
}
}

Answer 2

Swift 4.2
for emoji and special character
override func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
if textField.isFirstResponder {
let validString = CharacterSet(charactersIn: " !##$%^&*()_+{}[]|\"<>,.~`/:;?-=\\¥'£•¢")
if (textField.textInputMode?.primaryLanguage == "emoji") || textField.textInputMode?.primaryLanguage == nil {
return false
}
if let range = string.rangeOfCharacter(from: validString)
{
print(range)
return false
}
}
return true
}

Answer 3

One more answer with default CharacterSet
Restrict all Special characters and also, this will support if any string you dont want to restrict.
extension String {
var containsValidCharacter: Bool {
guard self != "" else { return true }
let noNeedToRestrict = CharacterSet(charactersIn: " _") // NOT RESTRICT "Underscore and Space"
if noNeedToRestrict.containsUnicodeScalars(of: self.last!) {
return true
} else {
return CharacterSet.alphanumerics.containsUnicodeScalars(of: self.last!)
}
}
}
extension CharacterSet {
func containsUnicodeScalars(of character: Character) -> Bool {
return character.unicodeScalars.allSatisfy(contains(_:))
}
}
Usage:
extension ViewController: UITextFieldDelegate {
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
return string.containsValidCharacter
}
}

Answer 4

Here's an example of how you can allow users to only type alphanumeric characters using RxSwift.
Add the RxSwift pod
pod 'RxSwift', '~> 5'
Create a String extension to remove characters in a set
extension String {
func removeChars(in set: CharacterSet) -> String {
let filtered = self.unicodeScalars.filter { (scalarElement) -> Bool in
if (set.contains(scalarElement)) {
return false
}
return true
}
let trimmed = String(filtered.map({ (scalar) -> Character in
return Character(scalar)
}))
return trimmed
}
}
Use the RxSwift extension to remove invalid chars when the text changes
import UIKit
import RxSwift
class MyViewController: UIViewController {
private let disposeBag = DisposeBag()
override func viewDidLoad() {
super.viewDidLoad()
setUpView()
}
private func setUpView() {
//Do view set up stuff here
//Use the extension here to listen to text changes and remove chars
myTextField.rx.text
.asDriver(onErrorJustReturn: "")
.drive(onNext: { [weak self] (text: String?) in
//Here you would change the character set to what you need
let newText = text?.removeChars(in: CharacterSet.alphanumerics.inverted)
self?.myTextField.text = newText
})
.disposed(by: disposeBag)
}
}

Answer 5

try with this
self.DataTblView.scrollToRow(at: IndexPath(row: 0, section: 0), at: .top, animated: false)