Understanding the Dependency Inversion Principle in Kotlin Android

Introduction

The Dependency Inversion Principle (DIP) is the fifth and final principle of the SOLID design principles in object-oriented programming. Introduced by Robert C. Martin, it says that high-level modules shouldn’t depend on low-level modules; both should depend on abstractions. Also, details should depend on abstractions, not the other way around.

The SOLID Foundation

DIP is the final piece of the SOLID principles:

• S: Single Responsibility Principle
• O: Open/Closed Principle
• L: Liskov Substitution Principle
• I: Interface Segregation Principle
• D: Dependency Inversion Principle

Each of these principles helps you write better, more manageable code. In this article, we’ll focus on Dependency Inversion, which ties everything together.

Understanding the Dependency Inversion Principle

At its core, DIP is about breaking tight connections between high-level logic and low-level details. Instead of directly depending on concrete classes, you use interfaces or abstract types to keep things flexible. Here are the main benefits: