Fix BottomSheet blinking

app/src/main/java/org/koitharu/kotatsu/base/ui/widgets/BottomSheetHeaderBar.kt

@@ -26,6 +26,8 @@ import org.koitharu.kotatsu.utils.ext.getAnimationDuration
 import org.koitharu.kotatsu.utils.ext.getThemeDrawable
 import org.koitharu.kotatsu.utils.ext.parents
 
+private const val THROTTLE_DELAY = 200L
+
 class BottomSheetHeaderBar @JvmOverloads constructor(
 	context: Context,
 	attrs: AttributeSet? = null,
@@ -35,6 +37,7 @@ class BottomSheetHeaderBar @JvmOverloads constructor(
 	private val binding = LayoutSheetHeaderBinding.inflate(LayoutInflater.from(context), this)
 	private val closeDrawable = context.getThemeDrawable(materialR.attr.actionModeCloseDrawable)
 	private val bottomSheetCallback = Callback()
+	private val adjustStateRunnable = Runnable { adjustState() }
 	private var bottomSheetBehavior: BottomSheetBehavior<*>? = null
 	private val locationBuffer = IntArray(2)
 	private val expansionListeners = LinkedList<OnExpansionChangeListener>()
@@ -43,6 +46,8 @@ class BottomSheetHeaderBar @JvmOverloads constructor(
 	private val maxHandleHeight = context.resources.getDimensionPixelSize(R.dimen.bottom_sheet_handle_size_max)
 	private var isLayoutSuppressedCompat = false
 	private var isLayoutCalledWhileSuppressed = false
+	private var isBsExpanded = false
+	private var stateAdjustedAt = 0L
 
 	@Deprecated("")
 	val toolbar: MaterialToolbar
@@ -173,16 +178,11 @@ class BottomSheetHeaderBar @JvmOverloads constructor(
 	}
 
 	private fun onBottomSheetStateChanged(newState: Int) {
-		val isExpanded = newState == BottomSheetBehavior.STATE_EXPANDED && isOnTopOfScreen()
-		if (isExpanded == binding.dragHandle.isGone) {
-			return
+		val expanded = newState == BottomSheetBehavior.STATE_EXPANDED && isOnTopOfScreen()
+		if (isBsExpanded != expanded) {
+			isBsExpanded = expanded
+			postAdjustState()
 		}
-		suppressLayoutCompat(true)
-		binding.toolbar.navigationIcon = (if (isExpanded) closeDrawable else null)
-		binding.dragHandle.isGone = isExpanded
-		expansionListeners.forEach { it.onExpansionStateChanged(this, isExpanded) }
-		dispatchInsets(ViewCompat.getRootWindowInsets(this))
-		suppressLayoutCompat(false)
 	}
 
 	private fun suppressLayoutCompat(suppress: Boolean) {
@@ -262,6 +262,26 @@ class BottomSheetHeaderBar @JvmOverloads constructor(
 		}
 	}
 
+	private fun postAdjustState() {
+		removeCallbacks(adjustStateRunnable)
+		val now = System.currentTimeMillis()
+		if (stateAdjustedAt + THROTTLE_DELAY < now) {
+			adjustState()
+		} else {
+			postDelayed(adjustStateRunnable, THROTTLE_DELAY)
+		}
+	}
+
+	private fun adjustState() {
+		suppressLayoutCompat(true)
+		binding.toolbar.navigationIcon = (if (isBsExpanded) closeDrawable else null)
+		binding.dragHandle.isGone = isBsExpanded
+		expansionListeners.forEach { it.onExpansionStateChanged(this, isBsExpanded) }
+		dispatchInsets(ViewCompat.getRootWindowInsets(this))
+		stateAdjustedAt = System.currentTimeMillis()
+		suppressLayoutCompat(false)
+	}
+
 	private inner class Callback : BottomSheetBehavior.BottomSheetCallback(), View.OnClickListener {
 
 		override fun onStateChanged(bottomSheet: View, newState: Int) {

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

@@ -1,9 +1,11 @@
 package org.koitharu.kotatsu.list.ui.filter
 
+import androidx.recyclerview.widget.AsyncListDiffer.ListListener
 import com.hannesdorfmann.adapterdelegates4.AsyncListDifferDelegationAdapter
 
 class FilterAdapter(
 	listener: OnFilterChangedListener,
+	listListener: ListListener<FilterItem>,
 ) : AsyncListDifferDelegationAdapter<FilterItem>(
 	FilterDiffCallback(),
 	filterSortDelegate(listener),
@@ -11,4 +13,9 @@ class FilterAdapter(
 	filterHeaderDelegate(),
 	filterLoadingDelegate(),
 	filterErrorDelegate(),
-)
+) {
+
+	init {
+		differ.addListListener(listListener)
+	}
+}

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

@@ -6,17 +6,21 @@ import android.os.Bundle
 import android.view.*
 import androidx.appcompat.widget.SearchView
 import androidx.fragment.app.FragmentManager
+import androidx.recyclerview.widget.AsyncListDiffer
+import androidx.recyclerview.widget.LinearLayoutManager
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.base.ui.BaseBottomSheet
 import org.koitharu.kotatsu.databinding.SheetFilterBinding
 import org.koitharu.kotatsu.remotelist.ui.RemoteListViewModel
+import org.koitharu.kotatsu.utils.ext.isScrolledToTop
 import org.koitharu.kotatsu.utils.ext.parentFragmentViewModels
 
 class FilterBottomSheet :
 	BaseBottomSheet<SheetFilterBinding>(),
 	MenuItem.OnActionExpandListener,
 	SearchView.OnQueryTextListener,
-	DialogInterface.OnKeyListener {
+	DialogInterface.OnKeyListener,
+	AsyncListDiffer.ListListener<FilterItem> {
 
 	private val viewModel by parentFragmentViewModels<RemoteListViewModel>()
 
@@ -32,7 +36,7 @@ class FilterBottomSheet :
 
 	override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
 		super.onViewCreated(view, savedInstanceState)
-		val adapter = FilterAdapter(viewModel)
+		val adapter = FilterAdapter(viewModel, this)
 		binding.recyclerView.adapter = adapter
 		viewModel.filterItems.observe(viewLifecycleOwner, adapter::setItems)
 		initOptionsMenu()
@@ -70,6 +74,12 @@ class FilterBottomSheet :
 		return false
 	}
 
+	override fun onCurrentListChanged(previousList: MutableList<FilterItem>, currentList: MutableList<FilterItem>) {
+		if (currentList.size > previousList.size && view != null) {
+			(binding.recyclerView.layoutManager as LinearLayoutManager).scrollToPositionWithOffset(0, 0)
+		}
+	}
+
 	private fun initOptionsMenu() {
 		binding.headerBar.toolbar.inflateMenu(R.menu.opt_filter)
 		val searchMenuItem = binding.headerBar.toolbar.menu.findItem(R.id.action_search)