Pagination loading indicator

app/src/main/java/org/koitharu/kotatsu/ui/common/list/BoundsScrollListener.kt

@@ -12,13 +12,15 @@ abstract class BoundsScrollListener(private val offsetTop: Int, private val offs
 		super.onScrolled(recyclerView, dx, dy)
 		val layoutManager = (recyclerView.layoutManager as? LinearLayoutManager) ?: return
 		val firstVisibleItemPosition = layoutManager.findFirstVisibleItemPosition()
+		if (firstVisibleItemPosition == RecyclerView.NO_POSITION) {
+			return
+		}
 		if (firstVisibleItemPosition <= offsetTop) {
 			onScrolledToStart(recyclerView)
-			return
 		}
 		val visibleItemCount = layoutManager.childCount
 		val totalItemCount = layoutManager.itemCount
-		if (visibleItemCount + firstVisibleItemPosition >= totalItemCount - offsetBottom && firstVisibleItemPosition >= 0) {
+		if (visibleItemCount + firstVisibleItemPosition >= totalItemCount - offsetBottom) {
 			onScrolledToEnd(recyclerView)
 		}
 	}

app/src/main/java/org/koitharu/kotatsu/ui/common/list/PaginationScrollListener.kt

@@ -2,24 +2,31 @@ package org.koitharu.kotatsu.ui.common.list
 
 import androidx.recyclerview.widget.RecyclerView
 
-class PaginationScrollListener(offset: Int, private val callback: Callback) : BoundsScrollListener(0, offset) {
+class PaginationScrollListener(offset: Int, private val callback: Callback) :
+	BoundsScrollListener(0, offset) {
 
 	private var lastTotalCount = 0
 
-	override fun onScrolledToStart(recyclerView: RecyclerView)  = Unit
+	override fun onScrolledToStart(recyclerView: RecyclerView) = Unit
 
 	override fun onScrolledToEnd(recyclerView: RecyclerView) {
-		val total = recyclerView.adapter?.itemCount ?: 0
+		val total = callback.getItemsCount()
 		if (total > lastTotalCount) {
-			callback.onRequestMoreItems(total)
 			lastTotalCount = total
+			callback.onRequestMoreItems(total)
 		} else if (total < lastTotalCount) {
 			lastTotalCount = total
 		}
 	}
 
+	fun reset() {
+		lastTotalCount = 0
+	}
+
 	interface Callback {
 
 		fun onRequestMoreItems(offset: Int)
+
+		fun getItemsCount(): Int
 	}
 }

app/src/main/java/org/koitharu/kotatsu/ui/common/list/ProgressBarAdapter.kt

@@ -4,7 +4,7 @@ import android.view.ViewGroup
 
 class ProgressBarAdapter : BaseRecyclerAdapter<Boolean, Unit>() {
 
-	var isVisible: Boolean
+	var isProgressVisible: Boolean
 		get() = dataSet.isNotEmpty()
 		set(value) {
 			if (value == dataSet.isEmpty()) {
@@ -20,5 +20,5 @@ class ProgressBarAdapter : BaseRecyclerAdapter<Boolean, Unit>() {
 
 	override fun onCreateViewHolder(parent: ViewGroup) = ProgressBarHolder(parent)
 
-	override fun onGetItemId(item: Boolean) = 1L
+	override fun onGetItemId(item: Boolean) = -1L
 }

app/src/main/java/org/koitharu/kotatsu/ui/common/list/ProgressBarHolder.kt

@@ -8,11 +8,27 @@ import org.koitharu.kotatsu.R
 class ProgressBarHolder(parent: ViewGroup) :
 	BaseViewHolder<Boolean, Unit>(parent, R.layout.item_progress) {
 
+	private var pendingVisibility: Int = View.GONE
+	private val action = Runnable {
+		progressBar?.visibility = pendingVisibility
+		pendingVisibility = View.GONE
+	}
+
 	override fun onBind(data: Boolean, extra: Unit) {
-		progressBar.visibility = if (data) {
+		val visibility = if (data) {
 			View.VISIBLE
 		} else {
 			View.INVISIBLE
 		}
+		if (visibility != progressBar.visibility && visibility != pendingVisibility) {
+			progressBar.removeCallbacks(action)
+			pendingVisibility = visibility
+			progressBar.postDelayed(action, 400)
+		}
+	}
+
+	override fun onRecycled() {
+		progressBar.removeCallbacks(action)
+		super.onRecycled()
 	}
 }

app/src/main/java/org/koitharu/kotatsu/ui/list/MangaListFragment.kt

@@ -9,10 +9,7 @@ import androidx.core.view.GravityCompat
 import androidx.core.view.isGone
 import androidx.core.view.isVisible
 import androidx.drawerlayout.widget.DrawerLayout
-import androidx.recyclerview.widget.DividerItemDecoration
+import androidx.recyclerview.widget.*
-import androidx.recyclerview.widget.GridLayoutManager
-import androidx.recyclerview.widget.LinearLayoutManager
-import androidx.recyclerview.widget.RecyclerView
 import androidx.swiperefreshlayout.widget.SwipeRefreshLayout
 import com.google.android.material.snackbar.Snackbar
 import kotlinx.android.synthetic.main.fragment_list.*
@@ -28,6 +25,7 @@ import org.koitharu.kotatsu.core.prefs.ListMode
 import org.koitharu.kotatsu.ui.common.BaseFragment
 import org.koitharu.kotatsu.ui.common.list.OnRecyclerItemClickListener
 import org.koitharu.kotatsu.ui.common.list.PaginationScrollListener
+import org.koitharu.kotatsu.ui.common.list.ProgressBarAdapter
 import org.koitharu.kotatsu.ui.common.list.decor.ItemTypeDividerDecoration
 import org.koitharu.kotatsu.ui.common.list.decor.SectionItemDecoration
 import org.koitharu.kotatsu.ui.common.list.decor.SpacingItemDecoration
@@ -38,14 +36,19 @@ import org.koitharu.kotatsu.utils.UiUtils
 import org.koitharu.kotatsu.utils.ext.*
 
 abstract class MangaListFragment<E> : BaseFragment(R.layout.fragment_list),
-	MangaListView<E>,
+	MangaListView<E>, PaginationScrollListener.Callback, OnRecyclerItemClickListener<Manga>,
-	PaginationScrollListener.Callback, OnRecyclerItemClickListener<Manga>,
 	SharedPreferences.OnSharedPreferenceChangeListener, OnFilterChangedListener,
 	SectionItemDecoration.Callback, SwipeRefreshLayout.OnRefreshListener {
 
 	private val settings by inject<AppSettings>()
+	private val adapterConfig = MergeAdapter.Config.Builder()
+		.setIsolateViewTypes(true)
+		.setStableIdMode(MergeAdapter.Config.StableIdMode.SHARED_STABLE_IDS)
+		.build()
 
 	private var adapter: MangaListAdapter? = null
+	private var progressAdapter: ProgressBarAdapter? = null
+	private var paginationListener : PaginationScrollListener? = null
 
 	override fun onCreate(savedInstanceState: Bundle?) {
 		super.onCreate(savedInstanceState)
@@ -56,10 +59,11 @@ abstract class MangaListFragment<E> : BaseFragment(R.layout.fragment_list),
 		super.onViewCreated(view, savedInstanceState)
 		drawer?.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED)
 		adapter = MangaListAdapter(this)
+		progressAdapter = ProgressBarAdapter()
+		paginationListener = PaginationScrollListener(4, this)
 		recyclerView.setHasFixedSize(true)
 		initListMode(settings.listMode)
-		// recyclerView.adapter = adapter
+		recyclerView.addOnScrollListener(paginationListener!!)
-		recyclerView.addOnScrollListener(PaginationScrollListener(4, this))
 		swipeRefreshLayout.setOnRefreshListener(this)
 		recyclerView_filter.setHasFixedSize(true)
 		recyclerView_filter.addItemDecoration(ItemTypeDividerDecoration(view.context))
@@ -72,6 +76,8 @@ abstract class MangaListFragment<E> : BaseFragment(R.layout.fragment_list),
 
 	override fun onDestroyView() {
 		adapter = null
+		progressAdapter = null
+		paginationListener = null
 		settings.unsubscribe(this)
 		super.onDestroyView()
 	}
@@ -123,6 +129,7 @@ abstract class MangaListFragment<E> : BaseFragment(R.layout.fragment_list),
 	}
 
 	override fun onListChanged(list: List<Manga>) {
+		paginationListener?.reset()
 		adapter?.replaceData(list)
 		if (list.isEmpty()) {
 			setUpEmptyListHolder()
@@ -130,11 +137,16 @@ abstract class MangaListFragment<E> : BaseFragment(R.layout.fragment_list),
 		} else {
 			layout_holder.isVisible = false
 		}
+		progressAdapter?.isProgressVisible = list.isNotEmpty()
 		recyclerView.callOnScrollListeners()
 	}
 
 	override fun onListAppended(list: List<Manga>) {
 		adapter?.appendData(list)
+		progressAdapter?.isProgressVisible = list.isNotEmpty()
+		if (list.isNotEmpty()) {
+			layout_holder.isVisible = false
+		}
 		recyclerView.callOnScrollListeners()
 	}
 
@@ -231,11 +243,19 @@ abstract class MangaListFragment<E> : BaseFragment(R.layout.fragment_list),
 		recyclerView.removeOnLayoutChangeListener(UiUtils.SpanCountResolver)
 		adapter?.listMode = mode
 		recyclerView.layoutManager = when (mode) {
-			ListMode.GRID -> GridLayoutManager(ctx, UiUtils.resolveGridSpanCount(ctx))
+			ListMode.GRID -> {
+				val spanCount = UiUtils.resolveGridSpanCount(ctx)
+				GridLayoutManager(ctx, spanCount).apply {
+					spanSizeLookup = object : GridLayoutManager.SpanSizeLookup() {
+						override fun getSpanSize(position: Int) = if (position < getItemsCount())
+							1 else spanCount
+					}
+				}
+			}
 			else -> LinearLayoutManager(ctx)
 		}
 		recyclerView.recycledViewPool.clear()
-		recyclerView.adapter = adapter
+		recyclerView.adapter = MergeAdapter(adapterConfig, adapter, progressAdapter)
 		recyclerView.addItemDecoration(
 			when (mode) {
 				ListMode.LIST -> DividerItemDecoration(ctx, RecyclerView.VERTICAL)
@@ -252,6 +272,8 @@ abstract class MangaListFragment<E> : BaseFragment(R.layout.fragment_list),
 		recyclerView.firstItem = position
 	}
 
+	override fun getItemsCount() = adapter?.itemCount ?: 0
+
 	final override fun isSection(position: Int): Boolean {
 		return position == 0 || recyclerView_filter.adapter?.run {
 			getItemViewType(position) != getItemViewType(position - 1)

app/src/main/java/org/koitharu/kotatsu/ui/list/MangaListSheet.kt

@@ -7,10 +7,7 @@ import android.view.View
 import androidx.appcompat.widget.Toolbar
 import androidx.core.view.isGone
 import androidx.core.view.isVisible
-import androidx.recyclerview.widget.DividerItemDecoration
+import androidx.recyclerview.widget.*
-import androidx.recyclerview.widget.GridLayoutManager
-import androidx.recyclerview.widget.LinearLayoutManager
-import androidx.recyclerview.widget.RecyclerView
 import com.google.android.material.bottomsheet.BottomSheetBehavior
 import com.google.android.material.bottomsheet.BottomSheetDialog
 import com.google.android.material.snackbar.Snackbar
@@ -27,6 +24,7 @@ import org.koitharu.kotatsu.core.prefs.ListMode
 import org.koitharu.kotatsu.ui.common.BaseBottomSheet
 import org.koitharu.kotatsu.ui.common.list.OnRecyclerItemClickListener
 import org.koitharu.kotatsu.ui.common.list.PaginationScrollListener
+import org.koitharu.kotatsu.ui.common.list.ProgressBarAdapter
 import org.koitharu.kotatsu.ui.common.list.decor.SpacingItemDecoration
 import org.koitharu.kotatsu.ui.details.MangaDetailsActivity
 import org.koitharu.kotatsu.utils.UiUtils
@@ -38,12 +36,18 @@ abstract class MangaListSheet<E> : BaseBottomSheet(R.layout.sheet_list),
 	SharedPreferences.OnSharedPreferenceChangeListener, Toolbar.OnMenuItemClickListener {
 
 	private val settings by inject<AppSettings>()
+	private val adapterConfig = MergeAdapter.Config.Builder()
+		.setIsolateViewTypes(true)
+		.setStableIdMode(MergeAdapter.Config.StableIdMode.SHARED_STABLE_IDS)
+		.build()
 
 	private var adapter: MangaListAdapter? = null
+	private var progressAdapter: ProgressBarAdapter? = null
 
 	override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
 		super.onViewCreated(view, savedInstanceState)
 		adapter = MangaListAdapter(this)
+		progressAdapter = ProgressBarAdapter()
 		initListMode(settings.listMode)
 		recyclerView.adapter = adapter
 		recyclerView.addOnScrollListener(PaginationScrollListener(4, this))
@@ -66,6 +70,7 @@ abstract class MangaListSheet<E> : BaseBottomSheet(R.layout.sheet_list),
 	override fun onDestroyView() {
 		settings.unsubscribe(this)
 		adapter = null
+		progressAdapter = null
 		super.onDestroyView()
 	}
 
@@ -123,6 +128,7 @@ abstract class MangaListSheet<E> : BaseBottomSheet(R.layout.sheet_list),
 	override fun onListChanged(list: List<Manga>) {
 		adapter?.replaceData(list)
 		textView_holder.isVisible = list.isEmpty()
+		progressAdapter?.isProgressVisible = list.isNotEmpty()
 		recyclerView.callOnScrollListeners()
 	}
 
@@ -131,6 +137,7 @@ abstract class MangaListSheet<E> : BaseBottomSheet(R.layout.sheet_list),
 		if (list.isNotEmpty()) {
 			textView_holder.isVisible = false
 		}
+		progressAdapter?.isProgressVisible = list.isNotEmpty()
 		recyclerView.callOnScrollListeners()
 	}
 
@@ -138,6 +145,8 @@ abstract class MangaListSheet<E> : BaseBottomSheet(R.layout.sheet_list),
 		Snackbar.make(recyclerView, e.getDisplayMessage(resources), Snackbar.LENGTH_SHORT).show()
 	}
 
+	override fun getItemsCount() = adapter?.itemCount ?: 0
+
 	override fun onInitFilter(
 		sortOrders: List<SortOrder>,
 		tags: List<MangaTag>,
@@ -171,10 +180,18 @@ abstract class MangaListSheet<E> : BaseBottomSheet(R.layout.sheet_list),
 		recyclerView.removeOnLayoutChangeListener(UiUtils.SpanCountResolver)
 		adapter?.listMode = mode
 		recyclerView.layoutManager = when (mode) {
-			ListMode.GRID -> GridLayoutManager(ctx, UiUtils.resolveGridSpanCount(ctx))
+			ListMode.GRID -> {
+				val spanCount = UiUtils.resolveGridSpanCount(ctx)
+				GridLayoutManager(ctx, spanCount).apply {
+					spanSizeLookup = object : GridLayoutManager.SpanSizeLookup() {
+						override fun getSpanSize(position: Int) = if (position < getItemsCount())
+							1 else spanCount
+					}
+				}
+			}
 			else -> LinearLayoutManager(ctx)
 		}
-		recyclerView.adapter = adapter
+		recyclerView.adapter = MergeAdapter(adapterConfig, adapter, progressAdapter)
 		recyclerView.addItemDecoration(
 			when (mode) {
 				ListMode.LIST -> DividerItemDecoration(ctx, RecyclerView.VERTICAL)

app/src/main/java/org/koitharu/kotatsu/ui/list/feed/FeedFragment.kt

@@ -102,6 +102,10 @@ class FeedFragment : BaseFragment(R.layout.fragment_tracklogs), FeedView,
 		}
 	}
 
+	override fun getItemsCount(): Int {
+		return adapter?.itemCount ?: 0
+	}
+
 	override fun onRequestMoreItems(offset: Int) {
 		presenter.loadList(offset)
 	}

app/src/main/java/org/koitharu/kotatsu/ui/list/feed/FeedPresenter.kt

@@ -25,13 +25,21 @@ class FeedPresenter : BasePresenter<FeedView>() {
 				val list = withContext(Dispatchers.IO) {
 					repository.getTrackingLog(offset, 20)
 				}
-				viewState.onListChanged(list)
+				if (offset == 0) {
+					viewState.onListChanged(list)
+				} else {
+					viewState.onListAppended(list)
+				}
 			} catch (e: CancellationException) {
 			} catch (e: Throwable) {
 				if (BuildConfig.DEBUG) {
 					e.printStackTrace()
 				}
-				viewState.onListError(e)
+				if (offset == 0) {
+					viewState.onListError(e)
+				} else {
+					viewState.onError(e)
+				}
 			} finally {
 				viewState.onLoadingStateChanged(false)
 			}

app/src/main/java/org/koitharu/kotatsu/ui/list/local/LocalListFragment.kt

@@ -23,9 +23,7 @@ class LocalListFragment : MangaListFragment<File>(), ActivityResultCallback<Uri>
 	private val presenter by moxyPresenter(factory = ::LocalListPresenter)
 
 	override fun onRequestMoreItems(offset: Int) {
-		if (offset == 0) {
+		presenter.loadList(offset)
-			presenter.loadList()
-		}
 	}
 
 	override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {

app/src/main/java/org/koitharu/kotatsu/ui/list/local/LocalListPresenter.kt

@@ -37,7 +37,11 @@ class LocalListPresenter : BasePresenter<MangaListView<File>>() {
 		super.onFirstViewAttach()
 	}
 
-	fun loadList() {
+	fun loadList(offset: Int) {
+		if (offset != 0) {
+			viewState.onListAppended(emptyList())
+			return
+		}
 		presenterScope.launch {
 			viewState.onLoadingStateChanged(true)
 			try {

app/src/main/java/org/koitharu/kotatsu/ui/search/global/GlobalSearchPresenter.kt

@@ -1,16 +1,12 @@
 package org.koitharu.kotatsu.ui.search.global
 
 import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.flow.catch
+import kotlinx.coroutines.flow.*
-import kotlinx.coroutines.flow.collect
-import kotlinx.coroutines.flow.flowOn
-import kotlinx.coroutines.flow.onEmpty
 import kotlinx.coroutines.launch
 import moxy.presenterScope
 import org.koitharu.kotatsu.domain.MangaSearchRepository
 import org.koitharu.kotatsu.ui.common.BasePresenter
 import org.koitharu.kotatsu.ui.list.MangaListView
-import org.koitharu.kotatsu.utils.ext.onFirst
 import java.io.IOException
 
 class GlobalSearchPresenter : BasePresenter<MangaListView<Unit>>() {
@@ -26,23 +22,27 @@ class GlobalSearchPresenter : BasePresenter<MangaListView<Unit>>() {
 	fun startSearch(query: String) {
 		presenterScope.launch {
 			viewState.onLoadingStateChanged(isLoading = true)
+			var isFirstCall = true
 			repository.globalSearch(query)
 				.flowOn(Dispatchers.IO)
 				.catch { e ->
 					if (e is IOException) {
 						viewState.onError(e)
 					}
-				}
+				}.filterNot { x -> x.isEmpty() }
-				.onFirst {
-					viewState.onListChanged(emptyList())
-					viewState.onLoadingStateChanged(isLoading = false)
-				}
 				.onEmpty {
 					viewState.onListChanged(emptyList())
 					viewState.onLoadingStateChanged(isLoading = false)
-				}
+				}.onCompletion {
-				.collect {
+					viewState.onListAppended(emptyList())
-					viewState.onListAppended(it)
+				}.collect {
+					if (isFirstCall) {
+						isFirstCall = false
+						viewState.onListChanged(it)
+						viewState.onLoadingStateChanged(isLoading = false)
+					} else {
+						viewState.onListAppended(it)
+					}
 				}
 		}
 	}

app/src/main/res/layout/item_progress.xml

@@ -9,6 +9,7 @@
 		android:id="@+id/progressBar"
 		style="@style/Widget.AppCompat.ProgressBar"
 		android:layout_width="wrap_content"
+		android:visibility="invisible"
 		android:layout_height="wrap_content"
 		android:layout_gravity="center" />