FormattableTextField

FormattableTextField

A UX-focused textfield formatter/validator built for bulletproof as-you-type formatting.

Features

• Built for as-you-type formatting
• Build your own bullet-proof formatters
• Cursor position is correct through input, delete, cut, and paste
• Delete across formatting characters
• Support for auto-advancing for complete textfields
• Support for interpreting backspace in an empty textfield as navigation to previous field
• Support for overflowing input from the end of a complete textfield to the next field

Usage

Create a FormattableTextField and assign it a TextFieldFormatter conforming formatter

let phoneNumberTextField: FormattableTextField = {
   let textField = FormattableTextField()
   textField.formatter = PhoneFormatter()
   textField.keyboardType = .phonePad
   return textField
}()

FormattableTextFieldDelegate

Assign the textField.delegate and implment any of the following methods to make experience decisions based on input.

public protocol FormattableTextFieldDelegate: UITextFieldDelegate {
    func textFieldShouldNavigateBackwards(_ textField: FormattableTextField)
    func textField(_ textField: FormattableTextField, didOverflowInput string: String)
    func textField(_ textField: FormattableTextField, invalidInput error: Error)
    func editingChanged(textField: FormattableTextField)
}

Creating A Formatter

Implement the TextFieldFormatter protocol to build your own formatter.

// A formatter to add spaces in between numbers
struct MyFormatter: TextFieldFormatter {
  var inputCharacterSet = CharacterSet.decimalDigits
  var formattingCharacterSet = CharacterSet(charactersIn: " ")
  
  func format(editingEvent: EditingEvent) -> FormattingResult {
      let formattedString = editingEvent.newValue.characters.map({String($0)}).joined(separator: " ")
      return .valid(.text(formattedString))
  }
}