Question:Paging with Room Datasource #36
Description
Hi, this is more a question than an issue, related to Room Datasource+LiveData PagedList.
I want to use selectable item feature of the OneAdapter, so i am trying to change currently working RecyclerView with PagedListAdapter.
But for OneAdapter, i need to ask PagedList from Room datasource to load next items , which i could not find how can it be done. As i understand PagedListAdapter requests next loading of items automatically by calculating Item size and recyclerview viewport size. and calls pagedlist.loadAround(Int) . I am not sure about the Int value passed here, its probably the internally maintained enumerated index of current list. I could not find how can i request next page to load in viewmodel. Did anyone can direct me how to use Room Paging Datasource with OneAdapter.?
OneAdapter Impl
object OneAdapters {
fun create(recyclerView: RecyclerView, onClick:(ModelEntity)->Unit,onCurrentBind:(Int)->Unit,loadMoreCall:(Int)->Unit) =OneAdapter(recyclerView){
itemModules+=ExperimentModelItem(onClick,onCurrentBind)
pagingModule=PagingModuleImpl(loadMoreCall)
}
internal class ExperimentModelItem(onClick: (ModelEntity) -> Unit,onCurrentBind: (Int) -> Unit) : ItemModule<ModelEntity>() {
init {
config {
layoutResource = R.layout.item_tile_list
}
onBind { model, viewBinder, metadata ->
viewBinder.bindings(ItemTileListBinding::bind).run {
onCurrentBind(metadata.position)
title.text = model.modelname
model.modified_at?.let { d ->
subtitle.text = "modified ${DateFormatHelper.readable(d)}"
}
}
}
onUnbind { model, viewBinder, _ ->
}
eventHooks += ClickEventHook<ModelEntity>().apply {
onClick { model, viewBinder, _ ->
onClick(model)
}
}
}
}
internal class PagingModuleImpl(loadMoreCall:(Int)->Unit) : PagingModule() {
init {
config {
layoutResource = R.layout.item_loading_progress// can be some spinner animation
visibleThreshold = 0 // invoke onLoadMore 3 items before the end
}
onLoadMore { currentPage ->
// place your load more logic here, like asking the ViewModel to load the next page of data.
loadMoreCall(currentPage)
}
}
}
}
Activity
private var mListMaxPosition: Int = 0
private val mRecyclerAdapter: OneAdapter by lazy {
OneAdapters.create(binding.explistActivityRecylerview, onClick = {
// navigate
},
onCurrentBind = {
if (it > mListMaxPosition)
mListMaxPosition = it
},
loadMoreCall = {
viewmodel.add(VMEvent.LoadMore(mListMaxPosition))
})
}
viewmodel
init{
val factory =repo.getAllModelsFactory()
val config = PagedList.Config.Builder()
.setEnablePlaceholders(false) // when true, the oneadapter's internal adapter crash on validating list having null models
.setInitialLoadSizeHint(15)
.setPageSize(5).build()
val pagedListBuilder: LivePagedListBuilder<Int, ModelEntity> = LivePagedListBuilder<Int,ModelEntity>(
factory,
config
)
models=pagedListBuilder.build() // observed LiveData in activity
}
fun onLoadMore(currentPage:Int) // called from activity,
{
models.value?.let {
// it.loadAround(currentPage) // max intPosition comming from activity
//it.loadAround(it.lastKey as Int)
}
}