Fix pages list scrolling

app/src/debug/kotlin/org/koitharu/kotatsu/KotatsuApp.kt

@@ -36,7 +36,7 @@ class KotatsuApp : BaseApp() {
 		FragmentStrictMode.defaultPolicy = FragmentStrictMode.Policy.Builder()
 			.penaltyDeath()
 			.detectFragmentReuse()
-			// .detectWrongFragmentContainer() FIXME: migrate to ViewPager2
+			.detectWrongFragmentContainer()
 			.detectRetainInstanceUsage()
 			.detectSetUserVisibleHint()
 			.detectFragmentTagUsage()

app/src/main/kotlin/org/koitharu/kotatsu/core/ui/list/fastscroll/FastScrollRecyclerView.kt

@@ -17,7 +17,16 @@ class FastScrollRecyclerView @JvmOverloads constructor(
 ) : RecyclerView(context, attrs, defStyleAttr) {
 
 	val fastScroller = FastScroller(context, attrs)
-	private var applyViewPager2Fix = false
+	var isVP2BugWorkaroundEnabled = false
+		set(value) {
+			field = value
+			if (value && isAttachedToWindow) {
+				checkIfInVP2()
+			} else if (!value) {
+				applyVP2Workaround = false
+			}
+		}
+	private var applyVP2Workaround = false
 
 	var isFastScrollerEnabled: Boolean = true
 		set(value) {
@@ -46,23 +55,29 @@ class FastScrollRecyclerView @JvmOverloads constructor(
 	override fun onAttachedToWindow() {
 		super.onAttachedToWindow()
 		fastScroller.attachRecyclerView(this)
-		applyViewPager2Fix = ancestors.any { it is ViewPager2 } == true
+		if (isVP2BugWorkaroundEnabled) {
+			checkIfInVP2()
+		}
 	}
 
 	override fun onDetachedFromWindow() {
 		fastScroller.detachRecyclerView()
 		super.onDetachedFromWindow()
-		applyViewPager2Fix = false
+		applyVP2Workaround = false
 	}
 
 	override fun isLayoutRequested(): Boolean {
-		return if (applyViewPager2Fix) false else super.isLayoutRequested()
+		return if (applyVP2Workaround) false else super.isLayoutRequested()
 	}
 
 	override fun requestLayout() {
 		super.requestLayout()
-		if (applyViewPager2Fix && parent?.isLayoutRequested == true) {
+		if (applyVP2Workaround && parent?.isLayoutRequested == true) {
 			parent?.requestLayout()
 		}
 	}
+
+	private fun checkIfInVP2() {
+		applyVP2Workaround = ancestors.any { it is ViewPager2 } == true
+	}
 }

app/src/main/kotlin/org/koitharu/kotatsu/details/ui/DetailsActivity.kt

@@ -363,8 +363,8 @@ class DetailsActivity :
 	}
 
 	private fun initPager() {
-		viewBinding.pager.recyclerView?.isNestedScrollingEnabled = false
 		val adapter = DetailsPagerAdapter(this)
+		viewBinding.pager.recyclerView?.isNestedScrollingEnabled = false
 		viewBinding.pager.offscreenPageLimit = 1
 		viewBinding.pager.adapter = adapter
 		TabLayoutMediator(viewBinding.tabs, viewBinding.pager, adapter).attach()

app/src/main/kotlin/org/koitharu/kotatsu/details/ui/pager/chapters/ChaptersFragment.kt

@@ -59,6 +59,7 @@ class ChaptersFragment :
 		with(binding.recyclerViewChapters) {
 			checkNotNull(selectionController).attachToRecyclerView(this)
 			setHasFixedSize(true)
+			isNestedScrollingEnabled = false
 			adapter = chaptersAdapter
 		}
 		viewModel.isLoading.observe(viewLifecycleOwner, this::onLoadingStateChanged)
@@ -83,6 +84,17 @@ class ChaptersFragment :
 		super.onDestroyView()
 	}
 
+	override fun onPause() {
+		// required for BottomSheetBehavior
+		requireViewBinding().recyclerViewChapters.isNestedScrollingEnabled = false
+		super.onPause()
+	}
+
+	override fun onResume() {
+		requireViewBinding().recyclerViewChapters.isNestedScrollingEnabled = true
+		super.onResume()
+	}
+
 	override fun onItemClick(item: ChapterListItem, view: View) {
 		if (selectionController?.onItemClick(item.chapter.id) == true) {
 			return

app/src/main/kotlin/org/koitharu/kotatsu/details/ui/pager/pages/PagesFragment.kt

@@ -88,6 +88,7 @@ class PagesFragment :
 			addItemDecoration(TypedListSpacingDecoration(context, false))
 			adapter = thumbnailsAdapter
 			setHasFixedSize(true)
+			isNestedScrollingEnabled = false
 			addOnLayoutChangeListener(spanResolver)
 			spanResolver?.setGridSize(settings.gridSize / 100f, this)
 			addOnScrollListener(ScrollListener().also { scrollListener = it })
@@ -112,6 +113,17 @@ class PagesFragment :
 		super.onDestroyView()
 	}
 
+	override fun onPause() {
+		// required for BottomSheetBehavior
+		requireViewBinding().recyclerView.isNestedScrollingEnabled = false
+		super.onPause()
+	}
+
+	override fun onResume() {
+		requireViewBinding().recyclerView.isNestedScrollingEnabled = true
+		super.onResume()
+	}
+
 	override fun onWindowInsetsChanged(insets: Insets) = Unit
 
 	override fun onItemClick(item: PageThumbnail, view: View) {

app/src/main/kotlin/org/koitharu/kotatsu/favourites/ui/list/FavouritesListFragment.kt

@@ -1,5 +1,6 @@
 package org.koitharu.kotatsu.favourites.ui.list
 
+import android.os.Bundle
 import android.view.Menu
 import android.view.MenuItem
 import android.view.View
@@ -12,6 +13,7 @@ import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.core.ui.list.ListSelectionController
 import org.koitharu.kotatsu.core.util.ext.sortedByOrdinal
 import org.koitharu.kotatsu.core.util.ext.withArgs
+import org.koitharu.kotatsu.databinding.FragmentListBinding
 import org.koitharu.kotatsu.list.domain.ListSortOrder
 import org.koitharu.kotatsu.list.ui.MangaListFragment
 import org.koitharu.kotatsu.parsers.model.MangaSource
@@ -26,6 +28,11 @@ class FavouritesListFragment : MangaListFragment(), PopupMenu.OnMenuItemClickLis
 	val categoryId
 		get() = viewModel.categoryId
 
+	override fun onViewBindingCreated(binding: FragmentListBinding, savedInstanceState: Bundle?) {
+		super.onViewBindingCreated(binding, savedInstanceState)
+		binding.recyclerView.isVP2BugWorkaroundEnabled = true
+	}
+
 	override fun onScrolledToEnd() = Unit
 
 	override fun onFilterClick(view: View?) {