UITextField Validation

UITextField_Validation.mm

    
// You can add/tailor the acceptable values here...
#define CHARACTERS          @" ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
#define CHARACTERS_NUMBERS  [CHARACTERS stringByAppendingString:@"1234567890"]
 
/*---------------------------------------------------
* Called whenever user enters/deletes character
*--------------------------------------------------*/
- (BOOL)textField:(UITextField *)textField 
    shouldChangeCharactersInRange:(NSRange)range 
    replacementString:(NSString *)string
{
  // These are the characters that are ~not~ acceptable
  NSCharacterSet *unacceptedInput =
    [[NSCharacterSet characterSetWithCharactersInString:CHARACTERS] invertedSet];
 
  // Create array of strings from incoming string using the unacceptable
  // characters as the trigger of where to split the string.
  // If array has more than one entry, there was at least one unacceptable character
  if ([[string componentsSeparatedByCharactersInSet:unacceptedInput] count] > 1)
    return NO;
  else 
    return YES;
}


//see http://iosdevelopertips.com/user-interface/validate-user-input-in-uitextfield-with-smarts-to-properly-manage-copy-and-paste.html



#define ALPHA                   @"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
#define NUMERIC                 @"1234567890"
#define ALPHA_NUMERIC           ALPHA NUMERIC

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    NSCharacterSet *unacceptedInput = nil;
    if ([[textField.text componentsSeparatedByString:@"@"] count] > 1) {
        unacceptedInput = [[NSCharacterSet characterSetWithCharactersInString:[ALPHA_NUMERIC stringByAppendingString:@".-"]] invertedSet];
    } else {
        unacceptedInput = [[NSCharacterSet characterSetWithCharactersInString:[ALPHA_NUMERIC stringByAppendingString:@".!#$%&'*+-/=?^_`{|}~@"]] invertedSet];
    }
    return ([[string componentsSeparatedByCharactersInSet:unacceptedInput] count] <= 1);
}  
//see http://stackoverflow.com/questions/7707906/how-to-check-if-uitextfields-text-is-valid-email

//Other possible solutions
//http://stackoverflow.com/questions/5428304/email-validation-on-textfield-in-iphone-sdk