PMValidation is a modular, extendable text validation library for iOS and tvOS. It comes with several common validation types for often-used tasks like validating registration forms, however it was architected to be easily extended with your own validation types. For a preliminary (but functional) Swift version of this lib, see PapersPlease.

Features

• Validate individual string objects or listen to changes from UIKit objects
• Modular – validation types can be used together to create complex validation constraints
• Extensible - Easily create your own validation types by subclassing PMValidationType
• Comes with several useful validation types to satisfy most validation needs
• Easily implement form validation by using PMValidationManager to register UIKit text input objects

Overview

At its simplest, PMValidation starts with an instance of a PMValidationType subclass. These classes provide the validation logic, and can be used directly if you just need a single validation test on your string. PMValidationType can be subclassed to provide your own custom validation logic. If you have a more complex validation test requiring several PMValidationType subclasses and need to determine an overall validation state for a string, use the PMValidationUnit class. When you need to validate more than one string and determine a global validation state (e.g. a validation form), the PMValidationManager class is useful. This class controls one or more PMValidationUnit objects, providing an overall validation status and notification routing. This class also simplifies the validation of UIKit text input classes.

Getting Started

The included validation form example project should give you a good overview of how PMValidation works.

The basics

Here's a basic example, creating a string length constraint which passes validation while the string is between 4 and 8 characters.

PMValidationLengthType *length_type = [PMValidationLengthType validator];
length_type.minimumCharacters = 4;
length_type.maximumCharacters = 8;

PMValidationUnit *unit = [PMValidationUnit validationUnit];
[unit registerValidationType:length_type];

// get validation status update
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(validationStatusNotificationHandler:) name:PMValidationUnitUpdateNotification object:unit];

// listen for validation status updates    
- (void)validationStatusNotificationHandler:(NSNotification *)notification {

  PMValidationUnit *unit = (PMValidationUnit *)notification.object;

  if (!unit.isValid) {
    NSDictionary *errors = [notification.userInfo valueForKey:@"errors"];
  }  

}


// validate the string 
[unit validateText:@"Velvet Underground"];

That example only uses one validation type class, but you can add as many as you want to create very complex validation tests. An alternative to chaining types together is to use the PMValidationRegexType class, which allows use of a regular expression as a validation test. For complex use cases this can be preferable – PMValidationEmailType uses a regular expression internally – but using more basic validation type classes together can provide greater readability and external customization. YMMV.

Validating static strings is cool, but let's hook up a PMValidationUnit to a UITextField so we can dynamically validate it as its text changes. While we could do this with just a PMValidationUnit, it's a bit easier to use PMValidationManager for this.

PMValidationManager *manager = [PMValidationManager validationManager];
PMValidationEmailType *email_type = [PMValidationEmailType validator];
PMValidationUnit *email_unit = [manager registerTextField:self.emailTextField
                                       forValidationTypes:[NSSet setWithObjects:email_type, nil]
                                               identifier:@"email"];

// get validation status update
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(validationStatusNotificationHandler:) name:PMValidationStatusNotification object:self.validationManager];


- (void)validationStatusNotificationHandler:(NSNotification *)notification {

  BOOL is_valid = [(NSNumber *)[notification.userInfo objectForKey:@"status"] boolValue];
  if (!is_valid) {
    NSDictionary *units = [notification.userInfo objectForKey:@"units"];
    NSDictionary *email_dict = [units objectForKey:email_type.identifier];
    NSDictionary *email_errors = [email_dict objectForKey:@"errors"];
  } 

}

Class reference

Credits

PMValidation was created by Brett Walker of Poet & Mountain.

Compatibility

• Requires iOS 6.0 or later
• PMValidation uses ARC.

License

PMValidation is licensed under the MIT License.