Hidden UITextfield's blink cursor.

uitextfield-hidecursor.swift

// Disable blink caret inspired from Joseph Chiu's answer on
// http://stackoverflow.com/questions/3699727/hide-the-cursor-of-an-uitextfield

extension UITextField {
  public override func caretRectForPosition(position: UITextPosition!) -> CGRect {
    if <# condition for hidden blink #> {
      return CGRectZero
    }
    return super.caretRectForPosition(position)
  }
}