FFCrimsonUnderscore

This library aims to help to handle validation process for large input forms comprised of UITextFields, UITextViews and any other UI elements whose text requires any sort of validation. It is designed to work in concert with the methods available in UITextFieldDelegate—creating a "live" and "realtime" validation experience aesthetic.

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#Installation Process

1. Copy FFCrimsonUnderscore to your project
2. Add

#import "FFCrimsonUnderscore.h" file

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#Usage

All that you need is to initialize FFValidationClient and implement FFValidationClientDelegate protocol.

Example:

NSArray *viewsToValidate = @[
    _textFieldEmail,
    _textFieldPassword
];

FFValidationClient *validationClient = [[FFValidationClient alloc] initWithViews:viewsToValidate];
validationClient.delegate = self;

[validationClient startValidationWithIndex:0
                              reverseOrder:NO];

Delegate implementation:

- (BOOL)validationClient:(FFValidationClient *)validationClient isViewValid:(UIView *)view errorAttributedText:(NSAttributedString **)errorAttributedText
{
    NSDictionary *attributesForValidationErrorText = {
        NSFontAttributeName: [UIFont fontWithName:@"HelveticaNeue" size:12.0f],
        NSForegroundColorAttributeName: [UIColor redColor]
    };

    if(view == _textFieldEmail)
    {
        NSString *textToValidate = _textFieldEmail.text;

        static NSString *emailRegularExpression = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";

        NSPredicate *emailPredicate = [NSPredicate predicateWithFormat:@"self matches %@",
            emailRegularExpression];

        BOOL isValidEmail = [emailPredicate evaluateWithObject:textToValidate];

        if(!isValidEmail)
        {
            *errorAttributedText = [[NSAttributedString alloc] initWithString:@"Wrong email."
                                                                   attributes:attributesForValidationErrorText];
        }

        return isValidEmail;
    }
    else if(view == _textFieldPassword)
    {
        NSString *textToValidate = _textFieldPassword.text;

        static NSUInteger minLengthForPassword = 8;

        BOOL isValidPassword = textToValidate.length >= minLengthForPassword;

        if(!isValidPassword)
        {
            NSString *errorText = [NSString stringWithFormat:@"Password cannot be less than %d symbols.",
                minLengthForPassword];

            *errorAttributedText = [[NSAttributedString alloc] initWithString:errorText
                                                                   attributes:attributesForValidationErrorText];
        }

        return isValidPassword;
    }
    else
    {
        return YES;
    }
}

FFValidationClientDelegate protocol provides a few other methods that one could use to finer tune their validation process (see demo src for usage). In most cases, however, it's enough to only implement the method above.