ViewModel

ViewModel is a design pattern and architectural component in software development, particularly prominent in Android development with Jetpack and in frameworks like MVVM (Model-View-ViewModel). It stores and manages UI-related data in a lifecycle-conscious way, surviving configuration changes such as screen rotations. This separates business logic from the UI, making apps more testable and maintainable.

Also known as: MVVM ViewModel, Android ViewModel, ViewModel pattern, UI ViewModel, ViewModel class

Why learn ViewModel?

Developers should learn ViewModel to build robust Android apps that handle configuration changes without data loss, as it decouples UI state from activities or fragments. It's essential for implementing the MVVM pattern, improving code organization, and enabling easier unit testing by isolating data handling from the UI layer. Use cases include managing live data for reactive UIs, handling user inputs, and persisting state across app restarts.

Learning Resources

• docs: Android Developers: ViewModel Overview
• tutorial: Google Codelabs: Android ViewModel
• course: Udacity: Android Kotlin Fundamentals - ViewModel
• video: YouTube: ViewModel Explained by Coding in Flow
• book: Book: Android Programming: The Big Nerd Ranch Guide