How do I add a custom validation rule in Validator?

Extend the Rule class and override the validate method, as shown in the README with the CustomRule example. This allows you to define any logic, such as checking for specific string matches or custom patterns.

Validator vs Android's built-in form validation: which is better?

Validator offers a more declarative approach with extensive pre-built rules and conditions, reducing boilerplate compared to manual validation. However, it's specifically for TextInputLayout, while built-in methods are more general but require more code.

Can I use Validator with Jetpack Compose?

No, Validator is designed for traditional Android Views, specifically TextInputLayout. For Jetpack Compose, you'd need to look for other validation libraries or implement custom solutions, as it doesn't support Compose's state management.

How to handle validation errors in Validator?

Use the listener-based callbacks; onValidateFailed provides a list of error messages that you can display in UI or log, as demonstrated in the example with Toast and Log calls for error handling.

Does Validator support async validation, like API calls?

Not directly; it focuses on synchronous, client-side validation. For server checks, you'd need to integrate async logic separately, such as using coroutines or callbacks outside the library's validation flow.

What's the difference between SINGLE and CONTINUOUS modes?

SINGLE mode validates all fields at once when triggered, useful for form submissions, while CONTINUOUS mode provides real-time feedback as the user types, enhancing UX for instant error correction, as illustrated with GIFs in the README.

Open-Awesome

Validator

MITKotlin

A Kotlin library for validating text input in Android TextInputLayout with built-in rules and custom rule support.

GitHub

129 stars9 forks0 contributors

What is Validator?

Validator is an Android library that provides a clean, declarative API for validating user input in TextInputLayout components. It solves the problem of repetitive and error-prone form validation code by offering a wide range of built-in validation rules and the ability to create custom rules. The library supports both single-batch and continuous validation modes with clear success/error callbacks.

Target Audience

Android developers building forms in Kotlin who need reliable input validation with minimal boilerplate code. Particularly useful for projects using Material Design's TextInputLayout components.

Value Proposition

Developers choose Validator for its extensive set of pre-built validation rules, intuitive conditional validation system, and seamless integration with Android's TextInputLayout. Its declarative Kotlin DSL makes validation logic easy to read and maintain compared to manual validation implementations.

Overview

A tool to validate text inside TextInputLayout

Use Cases

Best For

Validating login and registration forms in Android apps
Implementing real-time input validation with continuous feedback
Creating complex validation logic with AND/OR conditions
Adding custom validation rules beyond standard patterns
Reducing boilerplate code for form validation in Kotlin projects
Ensuring consistent validation across multiple TextInputLayout fields

Not Ideal For

Projects not using Android's Material Design TextInputLayout components
Teams preferring Java over Kotlin for Android development
Applications requiring validation on complex, non-input UI elements like custom views or dialogs
Projects needing built-in server-side or asynchronous validation calls

Pros & Cons

Pros

Extensive Built-in Rules

Includes over 25 predefined rules for common cases like email, password, and credit card validation, as listed in the README, reducing boilerplate code.

Flexible Conditional Validation

Supports AND/OR conditions with customizable error messages, enabling complex validation logic as shown in the username validation example.

Dual Validation Modes

Offers SINGLE for batch validation and CONTINUOUS for real-time feedback, with visual GIFs in the README demonstrating improved UX.

Easy Custom Rule Creation

Allows extending the base Rule class to create custom validation, exemplified by the CustomRule code snippet for tailored logic.

Cons

Limited to TextInputLayout

Specifically designed for TextInputLayout, making it unsuitable for other Android input components without additional workarounds or integrations.

Kotlin-Centric API

Uses a Kotlin DSL that may be less intuitive for Java-only projects, requiring Kotlin knowledge for optimal use, as seen in the code examples.

Dependency on JitPack

Distributed via JitPack instead of Maven Central, which some developers might find less stable or prefer for production-grade dependencies.

Frequently Asked Questions

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