Force Lowercase - iOS Swift

Force lowercase - ios swift

First you should set following property on your textfield to restrict auto capitalisation:

textfield.autocapitalizationType = UITextAutocapitalizationType.None

And this is how you can restrict it further:

func textField(textField: UITextField!, shouldChangeCharactersInRange range: NSRange, replacementString string: String!) -> Bool {

    if let _ = string.rangeOfCharacterFromSet(NSCharacterSet.uppercaseLetterCharacterSet()) {
        // Do not allow upper case letters
        return false
    }

    return true
}

UPDATED FOR SWIFT 4

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {

    if let _ = string.rangeOfCharacter(from: .uppercaseLetters) {
        // Do not allow upper case letters
        return false
    }

    return true
}

Swift -Force UITextview Lowercase Only

Instead of shouldChangeTextIn, use textViewDidChange.

extension ViewController: UITextViewDelegate {
    func textViewDidChange(_ textView: UITextView) {
        textView.text = textView.text.lowercased()
    }
}

Result:

Typing always (force) lowercase or uppercase - iOS swift

You should return false in if block because you already updated the textfield.

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
  if textField.isEqual(textFieldBodrum) {
     textFieldBodrum.text = (textField.text as NSString).stringByReplacingCharactersInRange(range, withString: string.lowercaseString)
     return false
  } else if textField.isEqual(textFieldYalikavak) {
                textFieldYalikavak.text = (textField.text as NSString).stringByReplacingCharactersInRange(range, withString: string.uppercaseString)
    return false
  }
   return true
}

If you don't want to affect other textfields you should return true end of the shouldChangeCharactersInRange function.

https://gist.github.com/fatihyildizhan/ac5f476aebd306b0580a1fa069f153a3

Force a UITextField to lowercase while typing and retaining cursor position

I have taken your code and tried this.

I can replace the cursor position wherever the text is changed.

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {

    let start = textField.positionFromPosition(textField.beginningOfDocument, offset:range.location)

    let cursorOffset = textField.offsetFromPosition(textField.beginningOfDocument, toPosition:start!) + string.characters.count

    textField.text = (textField.text! as NSString).stringByReplacingCharactersInRange(range, withString: string).lowercaseString

    let newCursorPosition = textField.positionFromPosition(textField.beginningOfDocument, offset:cursorOffset)

    let newSelectedRange = textField.textRangeFromPosition(newCursorPosition!, toPosition:newCursorPosition!)

    textField.selectedTextRange = newSelectedRange

    return false
}

SwiftUI TextField force lowercase

You can create a custom binding and set your state URL variable to the lowercased version of the input through it:

struct ContentView: View {
    @State var url: String = ""

    var body: some View {
        let binding = Binding<String>(get: {
            self.url
        }, set: {
            self.url = $0.lowercased()
        })

        return VStack {
            TextField("Enter URL", text: binding)
        }

    }
}

Force all attribute keys and values of a swift class in lowercase

Like this:

struct Person : Codable {
    var firstName: String
    var lastName: String
    var city: String
    enum CodingKeys : String, CodingKey {
        case firstName = "firstname"
        case lastName = "lastname"
        case city
    }
    func encode(to encoder: Encoder) throws {
        var con = encoder.container(keyedBy: CodingKeys.self)
        try! con.encode(self.firstName.lowercased(), forKey: .firstName)
        try! con.encode(self.lastName.lowercased(), forKey: .lastName)
        try! con.encode(self.city.lowercased(), forKey: .city)
    }
}

Testing it:

let person = Person(firstName: "David", lastName: "Gill", city:
    "Toronto")
let encoder = JSONEncoder()
let encoded = try encoder.encode(person)
print(String(decoding: encoded, as: UTF8.self))
// {"firstname":"david","lastname":"gill","city":"toronto"}

You can probably incorporate your .convertToLowerCase to save some work.

---

Related Topics