Swift live text field checking for characters from multiple arrays

Question

I have a text field which will serve as a password input. I have created 4 arrays

upperCaseAll = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"]

lowerCaseAll = ["a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"]

numberAll = [1 ,2, 3, 4, 5, 6, 7, 8, 9, 0]

specialCharAll = ["-", "/", ":", ";", "(", ")", "$", "&", "@", "\"", ".", ",", "?", "!", "'", "[", "]", "{", "}", "#", "%", "^", "\\", "|", "~", "<", ">", "€", "£", "¥", "•", ".", ","]

I am trying to make the user type at least one of each type of character. I have 4 text views that will turn from red to green once each rule is met. Then when all rules are met the red text views turn green and the login button is enabled

My question is how do I live check the text field to see if it has satisfied a rule? I imagine it would have to check each of the arrays overtime a character is entered

Oh also should the numbers be Ints or Strings?

Thanks

score 2 · Accepted Answer · answered Apr 27 '16 at 01:56

It's easier if you use Set instead of Array. Here's an example:

private let upperCaseAll = Set("ABCDEFGHIJKLMNOPQRSTUVWXYZ".characters)
private let lowerCaseAll = Set("abcdefghijklmnopqrstuvwxyz".characters)
private let numberAll = Set("0123456789".characters)
private let specialCharAll = Set("-/:;()$&@\".,?!'[]{}#%^\\|~<>€£¥".characters)

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
    // Determines what the new value of the text field will be
    let newText = range.length == 0 ? textField.text! + string : (textField.text! as NSString).stringByReplacingCharactersInRange(range, withString: string)

    // Turn that string into a Set of Characters
    let characters = Set(newText.characters)

    let hasUpperCase = !characters.intersect(self.upperCaseAll).isEmpty
    let hasLowerCase = !characters.intersect(self.lowerCaseAll).isEmpty
    let hasNumber = !characters.intersect(self.numberAll).isEmpty
    let hasSpecialChar = !characters.intersect(self.specialCharAll).isEmpty

    // Now turn your 4 other views to green/red as needed
    print("hasUpperCase = \(hasUpperCase), hasLowercase = \(hasLowerCase), hasNumber = \(hasNumber), hasSpecialChar = \(hasSpecialChar)")
    ...

    return true
}

Thank you very much. One thing if i type one of the characters...then delete it it does not undo the rule turning green — RubberDucky4444, Apr 27 '16 at 02:30
You have to change it in your code. It `has... == false`, you must set the corresponding view to white/transparent/red — Code Different, Apr 27 '16 at 02:33

score 1 · Answer 2 · answered Apr 26 '16 at 18:29

You can do it using the UITextFieldDelegate

See Apple Docs - textField(_:shouldChangeCharactersInRange:replacementString:)

The text field calls this method whenever user actions cause its text to change. Use this method to validate text as it is typed by the user. For example, you could use this method to prevent the user from entering anything but numerical values.

But you should think about using a regex to check the password string. That would be more convenient.

Thanks, I have been researching this delegate method more, do you have a solid example of how this would be done. Ive found some interesting results, one saying to change my arrays to a set (which i'm not against doing) Thanks — RubberDucky4444, Apr 26 '16 at 18:48

Swift live text field checking for characters from multiple arrays

2 Answers2