VictorAlbertos

pepepepepe

VictorAlbertos

class SampleFragment : Fragment(R.layout.sample_fragment) {
    private val viewModel: SampleViewModel by viewModels()
    private val sampleAdapter by lazy { SampleAdapter(viewModel) }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        val rvItems = view.findViewById<RecyclerView>(R.id.rvItems)
        rvItems.layoutManager = LinearLayoutManager(context)

VictorAlbertos

class SampleAdapter(private val sampleViewModel: SampleViewModel) :
    PagingDataAdapter<SampleEntity, SampleAdapter.ViewHolder>(Comparator) {

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        val sampleEntity = getItem(position) ?: return
        holder.itemView.findViewById<TextView>(R.id.tvItem).text = sampleEntity.name
        holder.itemView.findViewById<View>(R.id.ivRemove).setOnClickListener {
            sampleViewModel.onViewEvent(SampleViewEvents.Remove(sampleEntity))
        }
        holder.itemView.findViewById<View>(R.id.ivEdit).setOnClickListener {

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fun onViewEvent(sampleViewEvents: SampleViewEvents) {
    modificationEvents.value += sampleViewEvents
}

private fun applyEvents(paging: PagingData<SampleEntity>, sampleViewEvents: SampleViewEvents): PagingData<SampleEntity> {
    return when (sampleViewEvents) {
        is SampleViewEvents.Remove -> {
            paging
                .filter { sampleViewEvents.sampleEntity.id != it.id }
        }

VictorAlbertos

class SampleViewModel : ViewModel() {
    private val modificationEvents = MutableStateFlow<List<SampleViewEvents>>(emptyList())

    // combine them with the data coming from paging
    private val combined =
        Pager(PagingConfig(pageSize = SampleRepository.PAGE_SIZE)) { SamplePagingSource(SampleRepository()) }.flow
            .cachedIn(viewModelScope)
            .combine(modificationEvents) { pagingData, modifications ->
                modifications.fold(pagingData) { acc, event ->
                    applyEvents(acc, event)

VictorAlbertos

class SamplePagingSource(
    private val sampleRepository: SampleRepository
) : PagingSource<Int, SampleEntity>() {

    override suspend fun load(params: LoadParams<Int>): LoadResult<Int, SampleEntity> {
        return try {
            val data = sampleRepository.getNextPage(lastSeenId = params.key ?: 1)
                .map { SampleEntity(it, "Page number: $it") }
            LoadResult.Page(
                data = data,

VictorAlbertos

class SampleRepository {
    suspend fun getNextPage(lastSeenId: Int): List<Int> {
        return withContext(Dispatchers.IO) {
           (lastSeenId..lastSeenId + PAGE_SIZE).map { it }
        }
    }

    companion object {
        const val PAGE_SIZE = 20
    }

VictorAlbertos

sealed class SampleViewEvents {
    data class Edit(val sampleEntity: SampleEntity) : SampleViewEvents()
    data class Remove(val sampleEntity: SampleEntity) : SampleViewEvents()
    object InsertItemHeader : SampleViewEvents()
    object InsertItemFooter : SampleViewEvents()
}

VictorAlbertos

data class SampleEntity(val id: Int, val name: String)

VictorAlbertos

//read from loader
    api
      .compose(rxCache.<User>.read("mock").toObservable())
      .subscribe();
    
    //read without loader
    RxCache.<User>.read("mock")
        .toObservable()
        .subscribe();