app/src/main/java/org/pixeldroid/app/posts/feeds/uncachedFeeds/UncachedFeedFragment.kt
package org.pixeldroid.app.posts.feeds.uncachedFeeds
import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.lifecycle.ViewModel
import androidx.lifecycle.ViewModelProvider
import androidx.lifecycle.lifecycleScope
import androidx.paging.ExperimentalPagingApi
import androidx.paging.LoadState
import androidx.paging.PagingDataAdapter
import androidx.recyclerview.widget.RecyclerView
import androidx.swiperefreshlayout.widget.SwipeRefreshLayout
import kotlinx.coroutines.Job
import kotlinx.coroutines.flow.distinctUntilChangedBy
import kotlinx.coroutines.flow.filter
import kotlinx.coroutines.launch
import org.pixeldroid.app.databinding.FragmentFeedBinding
import org.pixeldroid.app.posts.feeds.initAdapter
import org.pixeldroid.app.posts.feeds.launch
import org.pixeldroid.app.utils.BaseFragment
import org.pixeldroid.app.utils.api.objects.FeedContent
import org.pixeldroid.app.utils.limitedLengthSmoothScrollToPosition
/**
* A fragment representing a list of [FeedContent], not backed by a db cache.
*/
open class UncachedFeedFragment<T: FeedContent> : BaseFragment() {
internal lateinit var viewModel: FeedViewModel<T>
internal lateinit var adapter: PagingDataAdapter<T, RecyclerView.ViewHolder>
var binding: FragmentFeedBinding? = null
private var job: Job? = null
internal fun launch() {
job = launch(job, lifecycleScope, viewModel, adapter)
}
internal fun initSearch() {
// Scroll to top when the list is refreshed from network.
lifecycleScope.launch {
adapter.loadStateFlow
// Only emit when REFRESH LoadState for RemoteMediator changes.
.distinctUntilChangedBy { it.refresh }
// Only react to cases where Remote REFRESH completes i.e., NotLoading.
.filter { it.refresh is LoadState.NotLoading }
.collect { binding?.list?.scrollToPosition(0) }
}
}
fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?, swipeRefreshLayout: SwipeRefreshLayout?
): View {
super.onCreateView(inflater, container, savedInstanceState)
binding = FragmentFeedBinding.inflate(layoutInflater)
binding!!.let {
initAdapter(
it.progressBar, swipeRefreshLayout ?: it.swipeRefreshLayout, it.list,
it.motionLayout, it.errorLayout, adapter
)
}
return binding!!.root
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
return onCreateView(inflater, container, savedInstanceState, null)
}
fun onTabReClicked() {
binding?.list?.limitedLengthSmoothScrollToPosition(0)
}
}
class ViewModelFactory<U: FeedContent> @ExperimentalPagingApi constructor(
private val searchContentRepository: UncachedContentRepository<U>
) : ViewModelProvider.Factory {
override fun <T : ViewModel> create(modelClass: Class<T>): T {
if (modelClass.isAssignableFrom(FeedViewModel::class.java)) {
@Suppress("UNCHECKED_CAST")
return FeedViewModel(searchContentRepository) as T
}
throw IllegalArgumentException("Unknown ViewModel class")
}
}