Architecture

This implementation is based on MVP + Clean architecture and S.O.L.I.D principles.

Inner layers know nothing about outer layers. This facilitates decoupling and testing.

Other software design patterns used in this project:

• Repository pattern

Packages definitions:

• data: It contains all the data accessing and manipulating components.
• domain: It contains all the business logic split in use cases.
• ui: View classes along with their corresponding Presenters.
• extensions: Kotlin extensions.
• mapper: Contains classes that facilitate model object mapping from one layer to another.
• di: Dependency providing classes using Koin.
• model:
  • Bo (business object),
  • Dto (data transfer object),
  • Uo (ui object),
  • Lo (local 'database' object).

Dependency Inversion - Injection

Koin has been chosen due to its simplicity and clarity. The only drawback is that the error checks are performed at runtime.

Despite Dagger being maintained by Google, it involves a lot of boilerplate setup.

Thread handling

Coroutines are being used in this implementation since as advised by the android community and throughout several Google IO'19 talks.

Networking

Retrofit 2.6.0 is the most popular and trusted networking library.

This version also enables to use it with Coroutines.

Database

Instead of Room database, Realm has been chosen due to its minimal configuration and great reliability.

Other considerations

• Image loading: Glide is one of the best async image loading libs out there. As benchmarks show, it's the fastest one when it comes to image downloading and loading from cache.
• Timber for logging: chosen for this project to save time while implementing the core functionality. It can be enhanced and fits well when the project needs to scale.

To improve

Code quality

• Integrate crashlytics or similar to have better insight of user runtime exceptions.
• Integrate continuous inspection of the code quality using SonarQube to perform automatic reviews static analysis of code to detect bugs, code smells, and security vulnerabilities.
• Integrate checks with a Kotlin linter with built-in formatter Ktlint.
• Add Cache validation strategy.

Screen rotation

Use ViewModel from Architecture Components to maintain state across device configuration changes.

Popular shows ordering

Current implementation loads tv show list from /tv/popular endpoint in pages.

Each page is ordered by tv show average rating.

This could be improved ordering every new page of items relative to all previous items. This would require to use DiffUtils and calling notifyItemRangeChanged instead of simply notifyItemRangeInserted

Demo