Phone Number Validation in iPhone SDK

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{

  int length = [self getLength:textField.text];

  if(length == 10)

  {

    if(range.length == 0)

        return NO;

  }

  if(length == 3)

  {

    NSString *num = [self formatNumber:textField.text];

    textField.text = [NSString stringWithFormat:@"(%@) ",num];

    if(range.length > 0)

        textField.text = [NSString stringWithFormat:@"%@",[num substringToIndex:3]];

  }

  else if(length == 6)

  {

    NSString *num = [self formatNumber:textField.text];

    

    textField.text = [NSString stringWithFormat:@"(%@) %@-",[num  substringToIndex:3],[num substringFromIndex:3]];

    if(range.length > 0)

        textField.text = [NSString stringWithFormat:@"(%@) %@",[num substringToIndex:3],[num substringFromIndex:3]];

  }

  return YES;

}

-(NSString*)formatNumber:(NSString*)mobileNumber

{

mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:@"(" withString:@""];

mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:@")" withString:@""];

mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:@" " withString:@""];

mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:@"-" withString:@""];

mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:@"+" withString:@""];

int length = [mobileNumber length];

if(length > 10)

{

    mobileNumber = [mobileNumber substringFromIndex: length-10];

}

return mobileNumber;

}

-(int)getLength:(NSString*)mobileNumber

{

  mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:@"(" withString:@""];

mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:@")" withString:@""];

mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:@" " withString:@""];

mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:@"-" withString:@""];

mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:@"+" withString:@""];

int length = [mobileNumber length];

return length;

}