When building software, especially scalable Android or enterprise applications like Hospital Management Systems (HMS) or Fleet/VTS platforms, developers often encounter the terms SOLID and MVVM. Many assume they are competing architectures, but in reality, they solve different problems.
Let’s break it down clearly.
What is SOLID?
SOLID is a set of five object-oriented design principles introduced by Robert C. Martin (Uncle Bob). It is not an architecture, but a rulebook for writing better code.
The 5 Principles:
- S — Single Responsibility Principle: A class should do only one job.
- O — Open/Closed Principle: Code should be open for extension, closed for modification.
- L — Liskov Substitution Principle: Subtypes must be replaceable with their base types.
- I — Interface Segregation Principle: Avoid forcing classes to implement unused methods.
- D — Dependency Inversion Principle: Depend on abstractions, not concrete implementations.
SOLID Helps You:
- Reduce tightly coupled code
- Improve testability
- Build maintainable modules
- Scale without breaking the system
These principles apply to backend APIs, Android apps, microservices, IoT platforms, analytics engines, and more.
What is MVVM Architecture?
MVVM (Model-View-ViewModel) is a software architecture pattern mainly used in UI-driven applications like Android, Flutter, Web dashboards, and desktop apps.
Core Layers in MVVM:
- Model → Holds the data
- View → UI layer (XML, Jetpack Compose, Web UI)
- ViewModel → Business logic + exposes observable state (LiveData, StateFlow, etc.)
MVVM Handles:
- UI and business logic separation
- Reactive data updates
- Lifecycle-safe state management
- Cleaner UI code
- Better structure for large apps
SOLID vs MVVM — The Key Difference
| SOLID | MVVM |
|---|---|
| Not an architecture, but principles | A complete UI architecture pattern |
| Focuses on class and module design | Focuses on UI data flow and state |
| Used anywhere (Backend, IoT, Apps, Web, HMS, FMS, VTS) | Mostly used in UI applications like Android |
| Makes code maintainable | Makes app structure maintainable |
In short: SOLID improves your code, MVVM improves your app design.
Can You Use SOLID with MVVM?
Absolutely — and you should!
A well-built MVVM project becomes even stronger when SOLID principles are applied in:
- ViewModel
- Repository Layer
- Use-Cases / Domain Logic
- Network & Database modules
- Dependency Injection (Hilt, Koin, Dagger)
This is especially useful for real-world projects like:
- Your Jindal Hospital HMS modules (OPD, IPD, Inventory, BMW, etc.)
- Your Fuel analytics & VTS intelligence platform at Glovision
- Any system requiring clean separation of concerns and scalable logic
Best Practices for MVVM + SOLID
✔ Keep View dumb, move logic to ViewModel
✔ Use Repository as a single data source handler
✔ Create interfaces/abstractions for repositories (Dependency Inversion)
✔ Split large ViewModels using Use-Cases (Single Responsibility)
✔ Inject dependencies instead of creating objects manually
✔ Write unit tests for ViewModel and domain logic
Sample Folder Structure
com.app.project
│── ui (View Layer)
│── viewmodel (ViewModel Layer)
│── repository (Data Handling)
│── network (API Services)
│── database (Room / Storage)
│── di (Dependency Injection)
│── domain (Use-Cases following SOLID)
Final Thought
It’s not SOLID vs MVVM — it’s SOLID inside MVVM.
Great software isn’t built just by choosing an architecture — it is built by structuring it well and writing quality code within it.