This is code challenge. See requirements in Android Coding Challenge.pdf
- Database is cleared each time app is re-started
- In order to query Pixabay API, please, add your personal key into :feature-images build.gradle file
buildConfigField("String", "TOKEN", "\"<token goes here>\"")- Jetpack libraries (viewModel, fragment-ktx, constraintLayout, recyclerView navigation)
- RxJava 3 + RxAndroid + RxKotlin
- Retrofit 2 + OkHttp + Moshi
- Room
- Hilt
- JUnit4 + Mockk
- application is modularized feature-wise.
- common module created to keep reusable code.
- maven dependency management done with the help of gradle platform module
- MVVM + data-binding
- dependency injection
- clean architecture (domain/data/ui separation within feature module)
- each layer has its own model which are converted subsequently: dto -> dbo -> domain -> view model
- dto reflects all data that is provided by API. Uses its own set of Annotations (Moshi)
- dbo reflects the way it is stored in db. Uses its own set of Annotations (Room).
Might also have different data types and simplified data structure. Is a subset of dto data - domain model reflects the subset of app's data necessary for particular business logic step
- view model reflects how domain data is presented
- it might to seem like over engineering, but only on the short run. Just imagine all above requirements merged into one class...
- each layer has its own model which are converted subsequently: dto -> dbo -> domain -> view model
- database as single source of data:
- UI reactively observes Db state
- if Db lacks data the remote data is requested (see repository implementation)
- ActivityDelegate used to propagate messages, navigation and loading events triggered in view models to where they can be consumed - Activity. ActivityDelegate is safe as it does not keep reference to any context and serves only as a relay
- proper exception handling
- e.g. mapping API exceptions to domain exceptions with meaningful for the user messages
- pagination for images list