The D in SOLID Principles

This is a codelab covering how to use KOIN, Manual and HILT Dependency Injection. The Demo application is built with Kotlin following MVVM architecture , it consumes tmdb api . https://github.com/valentineRutto/Movies/tree/droidconugdemo

Transcript

1. @valentinerutto The D in SOLID Principles ValentineRutto Native Android Developer https://linktr.ee/valentinerutto
2. S.O.L.I.D Principles Set of design guidelines to follow when building software so that it's easier to scale and maintain. • S -ingle responsibility A class should have a single responsibility • O-pen-Closed Classes should be open for extension, but closed for modification • L-iskov substitiution Objects of parent Class or its child Class can be used in the same way without any errors. • I-nterface segregation Clients should not be forced to depend on methods that they do not use. • D -ependency Inversion High-level modules should not depend on low-level modules but depend on abstraction.
3. Adobe Stock#243026154 What is DI? It is a technique whereby one object (or static method) supplies the dependencies of another object , instead of having it constructs them itself. Its responsible for: 1. Creating the objects 2. Knowing which classes require those objects 3. And provide them all those objects
4. Why You Should Care? • Helps in Unit testing. • Boiler plate code is reduced, as initializing of dependencies is done by the injector component. • Extending the application becomes easier. • Helps to enable loose coupling between classes and its dependencies.
5. Approaches
6. Adobe Stock#243026154 DI Frameworks:Hilt • Koin generates code based on objects and functions, which can be used to inject dependencies. • uses a runtime approach to generate boilerplate code for dependency injection KOIN • Jetpack recommended library • Removes boilerplate code via annotations. -generates code based on annotations which can be used to inject dependencies. • uses a compile-time approach to generate boilerplate code for dependency injection.
7. Adobe Stock#243026154 • Manage dependencies with a container class • Instances can be public or private • Add container class to the Application class for it to be available to whole application Manual DI
8. Implementation
9. Adobe Stock#243026154 Demo project: https://github.com/valentineRutto/Movies/tree/droidconugdemo
10. Questions
11. Resources • Demo project: https://github.com/valentineRutto/Movies/tree/droidconugdemo • https://www.geeksforgeeks.org/difference-between-dagger-hilt-koin-and-pure- dependency-injection/ • https://insert-koin.io/docs/quickstart/android • https://developer.android.com/training/dependency-injection/hilt-android • https://developer.android.com/training/dependency-injection/manual
12. Thank you! Android Developer @valentinerutto Valentine Rutto