Android Clean - Arch components

Using Dagger2 to manager class dependencies, using @BindsInstance to make the Context available in the graph

Database Module needs a context to initialize Room

@Module
class DatabaseModule{

    @Provides
    @Singleton
    fun providesRoom(context: Context) : AppDatabase {
        return Room
            .databaseBuilder(context, AppDatabase::class.java, "database-name")
            .build()
    }
}

Also using many RxJava2 approaches to transform complex objects into simpler objects.

apiService.get()
  .flatMapIterable { moviesMap ->
       moviesMap.entries.map { mapMovie ->
             Movie(
                  mapMovie.key,
                  mapMovie.value.rating,
                  mapMovie.value.synopsis,
                  mapMovie.value.title,
                  mapMovie.value.year
              )
         }
       }.toList()

Offline-first

Getting data from API

 private fun getMoviesFromAPI(): Observable<MutableList<Movie>> {
        return apiService.get()
            .flatMapIterable { moviesMap ->
                moviesMap.entries.map { mapMovie ->
                    Movie(
                        mapMovie.key,
                        mapMovie.value.rating,
                        mapMovie.value.synopsis,
                        mapMovie.value.title,
                        mapMovie.value.year
                    )
                }
            }
            .toList()
            .doAfterSuccess {
                appDatabase.movieDAO().insertAllMovies(it)
            }
            .toObservable()

 }

Getting data from local database

private fun getMoviesFromDB(): Observable<MutableList<Movie>> {
    return Observable.fromCallable {
        appDatabase.movieDAO().getAllMovie()
    }
}

Combining remote and local

fun getMovies(): Observable<MutableList<Movie>> {     
    return Observable.concatArray(getMoviesFromDB(), getMoviesFromAPI())
}

Libraries used

• AndroidX
• Dagger 2
• Retrofit 2
• ViewModel
• LiveData
• RxJava 2
• RxAndroid
• Jetpack Navigation
• Room
• Data Binding

License

Copyright 2018 Anderson Caxias

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.