This repository is all about Paging3 implementation for various use cases like
- Paging using network (retrofit) as data source
- Paging using network and local db room.
- Showing footer error view or loading states.
@ExperimentalPagingApi
class ShowMediator(val showApiService: ShowApiService,
val appDatabase: AppDatabase,
var show_searcch_key: String
) :RemoteMediator<Int, Search>() {
override suspend fun load(
loadType: LoadType, state: PagingState<Int, Search>
): MediatorResult {
try {
val pageKeyData = getKeyPageData(loadType, state)
val page = when (pageKeyData) {
is MediatorResult.Success -> {
return pageKeyData
}
else -> {
pageKeyData as Int
}
}
val response = showApiService
.getShowImages(page, state.config.pageSize, show_searcch_key)
var response_search= response.Search
val isEndOfList = response_search.isEmpty()
appDatabase.withTransaction {
// clear all tables in the database
if (loadType == LoadType.REFRESH) {
appDatabase.getRepoDao().clearRemoteKeys()
appDatabase.getShowsDao().clearAllDoggos()
}
val prevKey = if(page.equals(DEFAULT_PAGE_INDEX)) null else page - 1
val nextKey = if (isEndOfList) null else page + 1
val keys = response_search.map {
RemoteKeys(repoId = it.imdbID, prevKey = prevKey, nextKey = nextKey)
}
appDatabase.getRepoDao().insertAll(keys)
appDatabase.getShowsDao().insertAll(response_search)
}
return MediatorResult.Success(endOfPaginationReached = isEndOfList)
} catch (exception: IOException) {
return MediatorResult.Error(exception)
} catch (exception: HttpException) {
return MediatorResult.Error(exception)
}
}
override fun letDoggoImagesFlowDb(pagingConfig: PagingConfig, show_searcch_key: String): Flow<PagingData<Search>> {
val pagingSourceFactory = { appDatabase.getShowsDao().getAllShowModel() }
val dm = ShowMediator(showApiService, appDatabase, show_searcch_key)
return Pager(
config = pagingConfig,
pagingSourceFactory = pagingSourceFactory,
remoteMediator = dm
).flow
}class RoomViewModel @ViewModelInject constructor(
val repository: ShowImagesRepo
) :
ViewModel() {
var searched_key: String= "russia"
fun fetchShowsImages(): Flow<PagingData<Search>> {
return repository.letDoggoImagesFlowDb(
repository.getDefaultPageConfig(), searched_key).cachedIn(viewModelScope)
}
[RoomShowImageAdapter](app/src/main/java/com/taghda/cinema_news/view/room/adapter/RoomShowImageAdapter.kt):
class RoomShowImageAdapter :
PagingDataAdapter<Search, RoomShowImageAdapter.ShowsImageViewHolder>(REPO_COMPARATOR) {
[RoomFragment](app/src/main/java/com/taghda/cinema_news/view/room/RoomFragment.kt) :
private fun fetchDoggoImages() {
lifecycleScope.launch {
roomViewModel.fetchShowsImages().distinctUntilChanged().collectLatest {
adapter.submitData(it)
}
}
}
private fun initMembers() {
// roomViewModel = defaultViewModelProviderFactory.create(RoomViewModel::class.java)
adapter = RoomShowImageAdapter()
loaderStateAdapter = LoaderStateAdapter { adapter.retry() }
}
private fun setUpViews(view: View) {
recyclerView = view.findViewById(R.id.rvDoggoRoom)
searchEditText = view.findViewById(R.id.input)
recyclerView.layoutManager = LinearLayoutManager(context)
recyclerView.adapter = adapter.withLoadStateFooter(loaderStateAdapter)
}
}