gistfile1.txt

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
	
	//NSLog(@"textfield hit: %@", textField.placeholder);
	
	
	if (string.length == 0) {
        return YES;
    }
	
	
	if (textField == self.CardholderName) {
		return  YES;
		
	} else {

		
		NSUInteger newLength = [textField.text length] + [string length] - range.length;
		
		if (textField == self.CardNumber) {
			if (newLength > 16) {
				return NO;
			}
		}
		
		if (textField == self.ExpiryDate) {
			if (newLength > 4) {
				return NO;
			}
		}
		
		if (textField == self.CCV) {
			if (newLength > 4) {
				return NO;
			}
		}
		
		if (textField == self.ZipCode) {
			if (newLength > 5) {
				return NO;
			}
		}
		
		NSCharacterSet *nonNumberSet = [[NSCharacterSet decimalDigitCharacterSet] invertedSet];
		

		return [string rangeOfCharacterFromSet:nonNumberSet].location == NSNotFound;
	}

	return NO;
}