Fix ChaptersPagesSheet nested scrolling

app/src/main/kotlin/org/koitharu/kotatsu/core/ui/util/PagerNestedScrollHelper.kt

@@ -0,0 +1,50 @@
+package org.koitharu.kotatsu.core.ui.util
+
+import android.view.View
+import androidx.coordinatorlayout.widget.CoordinatorLayout
+import androidx.core.view.ancestors
+import androidx.lifecycle.DefaultLifecycleObserver
+import androidx.lifecycle.Lifecycle.State.RESUMED
+import androidx.lifecycle.LifecycleOwner
+import androidx.recyclerview.widget.RecyclerView
+import com.google.android.material.bottomsheet.BottomSheetBehavior
+
+class PagerNestedScrollHelper(
+	private val recyclerView: RecyclerView,
+) : DefaultLifecycleObserver {
+
+	fun bind(lifecycleOwner: LifecycleOwner) {
+		lifecycleOwner.lifecycle.addObserver(this)
+		recyclerView.isNestedScrollingEnabled = lifecycleOwner.lifecycle.currentState.isAtLeast(RESUMED)
+	}
+
+	override fun onPause(owner: LifecycleOwner) {
+		recyclerView.isNestedScrollingEnabled = false
+		invalidateBottomSheetScrollTarget()
+	}
+
+	override fun onResume(owner: LifecycleOwner) {
+		recyclerView.isNestedScrollingEnabled = true
+	}
+
+	override fun onDestroy(owner: LifecycleOwner) {
+		owner.lifecycle.removeObserver(this)
+	}
+
+	/**
+	 * Here we need to invalidate the `nestedScrollingChildRef` of the [BottomSheetBehavior]
+	 */
+	private fun invalidateBottomSheetScrollTarget() {
+		var handleCoordinator = false
+		for (parent in recyclerView.ancestors) {
+			if (handleCoordinator && parent is CoordinatorLayout) {
+				parent.requestLayout()
+				break
+			}
+			val lp = (parent as? View)?.layoutParams ?: continue
+			if (lp is CoordinatorLayout.LayoutParams && lp.behavior is BottomSheetBehavior<*>) {
+				handleCoordinator = true
+			}
+		}
+	}
+}

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

@@ -156,7 +156,6 @@ class DetailsActivity :
 		viewBinding.chipsTags.onChipClickListener = this
 		TitleScrollCoordinator(viewBinding.textViewTitle).attach(viewBinding.scrollView)
 		viewBinding.containerBottomSheet?.let { BottomSheetBehavior.from(it) }?.let { behavior ->
-			behavior.addBottomSheetCallback(BottomSheetNoHalfExpandedCallback())
 			onBackPressedDispatcher.addCallback(BottomSheetClollapseCallback(behavior))
 		}
 

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

@@ -25,6 +25,7 @@ import org.koitharu.kotatsu.core.util.ext.doOnPageChanged
 import org.koitharu.kotatsu.core.util.ext.menuView
 import org.koitharu.kotatsu.core.util.ext.observe
 import org.koitharu.kotatsu.core.util.ext.observeEvent
+import org.koitharu.kotatsu.core.util.ext.recyclerView
 import org.koitharu.kotatsu.core.util.ext.setTabsEnabled
 import org.koitharu.kotatsu.core.util.ext.showDistinct
 import org.koitharu.kotatsu.core.util.ext.withArgs
@@ -56,6 +57,7 @@ class ChaptersPagesSheet : BaseAdaptiveSheet<SheetChaptersPagesBinding>(), Actio
 			defaultTab = (defaultTab - 1).coerceAtLeast(TAB_CHAPTERS)
 		}
 		binding.pager.offscreenPageLimit = adapter.itemCount
+		binding.pager.recyclerView?.isNestedScrollingEnabled = false
 		binding.pager.adapter = adapter
 		binding.pager.doOnPageChanged(::onPageChanged)
 		TabLayoutMediator(binding.tabs, binding.pager, adapter).attach()

app/src/main/kotlin/org/koitharu/kotatsu/details/ui/pager/bookmarks/MangaBookmarksFragment.kt

@@ -15,6 +15,7 @@ import org.koitharu.kotatsu.bookmarks.ui.sheet.BookmarksAdapter
 import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.core.ui.BaseFragment
 import org.koitharu.kotatsu.core.ui.list.OnListItemClickListener
+import org.koitharu.kotatsu.core.ui.util.PagerNestedScrollHelper
 import org.koitharu.kotatsu.core.util.ext.dismissParentDialog
 import org.koitharu.kotatsu.core.util.ext.findParentCallback
 import org.koitharu.kotatsu.core.util.ext.observe
@@ -69,6 +70,8 @@ class MangaBookmarksFragment : BaseFragment<FragmentMangaBookmarksBinding>(),
 		viewModel.gridScale.observe(viewLifecycleOwner, ::onGridScaleChanged) // before rv initialization
 		with(binding.recyclerView) {
 			addItemDecoration(TypedListSpacingDecoration(context, false))
+			setHasFixedSize(true)
+			PagerNestedScrollHelper(this).bind(viewLifecycleOwner)
 			adapter = bookmarksAdapter
 			addOnLayoutChangeListener(spanResolver)
 			(layoutManager as GridLayoutManager).let {
@@ -76,7 +79,7 @@ class MangaBookmarksFragment : BaseFragment<FragmentMangaBookmarksBinding>(),
 				it.spanCount = checkNotNull(spanResolver).spanCount
 			}
 		}
-		viewModel.content.observe(viewLifecycleOwner, checkNotNull(bookmarksAdapter))
+		viewModel.content.observe(viewLifecycleOwner) { bookmarksAdapter?.setItems(it, listCommitCallback) }
 	}
 
 	override fun onDestroyView() {
@@ -86,17 +89,6 @@ class MangaBookmarksFragment : BaseFragment<FragmentMangaBookmarksBinding>(),
 		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: Bookmark, view: View) {

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

@@ -22,6 +22,7 @@ import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.core.ui.BaseFragment
 import org.koitharu.kotatsu.core.ui.list.ListSelectionController
 import org.koitharu.kotatsu.core.ui.list.OnListItemClickListener
+import org.koitharu.kotatsu.core.ui.util.PagerNestedScrollHelper
 import org.koitharu.kotatsu.core.util.RecyclerViewScrollCallback
 import org.koitharu.kotatsu.core.util.ext.dismissParentDialog
 import org.koitharu.kotatsu.core.util.ext.findAppCompatDelegate
@@ -80,7 +81,7 @@ class ChaptersFragment :
 			addItemDecoration(TypedListSpacingDecoration(context, true))
 			checkNotNull(selectionController).attachToRecyclerView(this)
 			setHasFixedSize(true)
-			isNestedScrollingEnabled = false
+			PagerNestedScrollHelper(this).bind(viewLifecycleOwner)
 			adapter = chaptersAdapter
 			ChapterGridSpanHelper.attach(this)
 		}
@@ -101,17 +102,6 @@ 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

@@ -22,6 +22,7 @@ import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.core.ui.BaseFragment
 import org.koitharu.kotatsu.core.ui.list.BoundsScrollListener
 import org.koitharu.kotatsu.core.ui.list.OnListItemClickListener
+import org.koitharu.kotatsu.core.ui.util.PagerNestedScrollHelper
 import org.koitharu.kotatsu.core.util.RecyclerViewScrollCallback
 import org.koitharu.kotatsu.core.util.ext.dismissParentDialog
 import org.koitharu.kotatsu.core.util.ext.findParentCallback
@@ -93,7 +94,7 @@ class PagesFragment :
 			addItemDecoration(TypedListSpacingDecoration(context, false))
 			adapter = thumbnailsAdapter
 			setHasFixedSize(true)
-			isNestedScrollingEnabled = false
+			PagerNestedScrollHelper(this).bind(viewLifecycleOwner)
 			addOnLayoutChangeListener(spanResolver)
 			addOnScrollListener(ScrollListener().also { scrollListener = it })
 			(layoutManager as GridLayoutManager).let {
@@ -117,17 +118,6 @@ 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/res/layout/activity_details.xml

@@ -406,7 +406,7 @@
 		android:nestedScrollingEnabled="false"
 		android:outlineProvider="background"
 		app:behavior_fitToContents="false"
-		app:behavior_halfExpandedRatio="0.00001"
+		app:behavior_halfExpandedRatio="0.8"
 		app:behavior_hideable="false"
 		app:behavior_peekHeight="@dimen/details_bs_peek_height"
 		app:layout_behavior="com.google.android.material.bottomsheet.BottomSheetBehavior"