Jump to category using the backdrop on the top of the library

Along with only showing a single category at a time

app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferencesHelper.kt

@@ -263,6 +263,8 @@ class PreferencesHelper(val context: Context) {
 
     fun deleteRemovedChapters() = flowPrefs.getInt(Keys.deleteRemovedChapters, 0)
 
+    fun showAllCategories() = flowPrefs.getBoolean("show_all_categories", true)
+
     // Tutorial preferences
     fun shownFilterTutorial() = flowPrefs.getBoolean("shown_filter_tutorial", false)
 

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryCategoryAdapter.kt

@@ -21,8 +21,8 @@ import kotlin.math.max
  *
  * @param view the fragment containing this adapter.
  */
-class LibraryCategoryAdapter(val libraryListener: LibraryListener) :
+class LibraryCategoryAdapter(val controller: LibraryController) :
-        FlexibleAdapter<IFlexible<*>>(null, libraryListener, true) {
+        FlexibleAdapter<IFlexible<*>>(null, controller, true) {
 
     init {
         setDisplayHeadersAtStartUp(true)
@@ -32,6 +32,8 @@ class LibraryCategoryAdapter(val libraryListener: LibraryListener) :
      */
     private var mangas: List<LibraryItem> = emptyList()
 
+    val libraryListener: LibraryListener = controller
+
     /**
      * Sets a list of manga in the adapter.
      *
@@ -97,13 +99,18 @@ class LibraryCategoryAdapter(val libraryListener: LibraryListener) :
         val preferences: PreferencesHelper by injectLazy()
         val db: DatabaseHelper by injectLazy()
         if (position == itemCount - 1) return "-"
-        val sorting = if (preferences.hideCategories().getOrDefault())
+        val sorting = if (!preferences.showAllCategories().get()) {
-            preferences.hideCategories().getOrDefault()
+            controller.presenter.getCurrentCategory()?.sortingMode() ?: LibrarySort.DRAG_AND_DROP
-        else (headerItems.firstOrNull() as? LibraryHeaderItem)?.category?.sortingMode()
+        } else if (preferences.hideCategories().getOrDefault()) {
-        ?: LibrarySort.DRAG_AND_DROP
+            preferences.librarySortingMode().getOrDefault()
+        } else {
+            (headerItems.firstOrNull() as? LibraryHeaderItem)?.category?.sortingMode()
+                ?: LibrarySort.DRAG_AND_DROP
+        }
         return when (val item: IFlexible<*>? = getItem(position)) {
             is LibraryHeaderItem ->
-                if (preferences.hideCategories().getOrDefault() || item.category.id == 0) null
+                if (preferences.hideCategories().getOrDefault() || item.category.id == 0 ||
+                    !preferences.showAllCategories().get()) null
                 else getFirstChar(item.category.name) +
                     "\u200B".repeat(max(0, item.category.order))
             is LibraryItem -> {
@@ -123,11 +130,11 @@ class LibraryCategoryAdapter(val libraryListener: LibraryListener) :
                     }
                     LibrarySort.TOTAL -> {
                         val unread = item.chapterCount
-                        (unread / 100).toString()
+                        getShortRange(unread)
                     }
                     LibrarySort.UNREAD -> {
                         val unread = item.manga.unread
-                        if (unread > 0) (unread / 100).toString()
+                        if (unread > 0) getShortRange(unread)
                         else "R"
                     }
                     LibrarySort.LATEST_CHAPTER -> {
@@ -168,7 +175,9 @@ class LibraryCategoryAdapter(val libraryListener: LibraryListener) :
                 else recyclerView.context.getString(R.string.top)
             is LibraryItem -> {
                 if (iFlexible.manga.isBlank()) ""
-                else when (preferences.librarySortingMode().getOrDefault()) {
+                else when (if (!preferences.showAllCategories().get()) {
+                    controller.presenter.getCurrentCategory()?.sortingMode() ?: LibrarySort.DRAG_AND_DROP
+                } else preferences.librarySortingMode().getOrDefault()) {
                     LibrarySort.DRAG_AND_DROP -> {
                         if (!preferences.hideCategories().getOrDefault()) {
                             val title = iFlexible.manga.title
@@ -225,18 +234,36 @@ class LibraryCategoryAdapter(val libraryListener: LibraryListener) :
         }
     }
 
+    private fun getShortRange(value: Int): String {
+        return when (value) {
+            1 -> "1"
+            2 -> "2"
+            3 -> "3"
+            4 -> "4"
+            5 -> "5"
+            in 6..10 -> "6"
+            in 11..50 -> "10"
+            in 51..100 -> "50"
+            in 101..500 -> "1+"
+            in 499..899 -> "4+"
+            in 901..Int.MAX_VALUE -> "9+"
+            else -> "0"
+        }
+    }
+
     private fun getRange(value: Int): String {
         return when (value) {
-            in 1..99 -> "< 100"
+            1 -> "1"
-            in 100..199 -> "100-199"
+            2 -> "2"
-            in 200..299 -> "200-299"
+            3 -> "3"
-            in 300..399 -> "300-399"
+            4 -> "4"
-            in 400..499 -> "400-499"
+            5 -> "5"
-            in 500..599 -> "500-599"
+            in 6..10 -> "6-10"
-            in 600..699 -> "600-699"
+            in 11..50 -> "11-50"
-            in 700..799 -> "700-799"
+            in 51..100 -> "51-100"
-            in 800..899 -> "800-899"
+            in 101..500 -> "100-500"
-            in 900..Int.MAX_VALUE -> "900+"
+            in 499..899 -> "499-900"
+            in 901..Int.MAX_VALUE -> "900+"
             else -> "None"
         }
     }

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryController.kt

@@ -1,5 +1,6 @@
 package eu.kanade.tachiyomi.ui.library
 
+import android.animation.ValueAnimator
 import android.app.Activity
 import android.content.Context
 import android.graphics.Color
@@ -16,6 +17,7 @@ import android.view.inputmethod.InputMethodManager
 import androidx.appcompat.app.AppCompatActivity
 import androidx.appcompat.view.ActionMode
 import androidx.appcompat.widget.SearchView
+import androidx.recyclerview.widget.DefaultItemAnimator
 import androidx.recyclerview.widget.GridLayoutManager
 import androidx.recyclerview.widget.ItemTouchHelper
 import androidx.recyclerview.widget.LinearLayoutManager
@@ -56,10 +58,11 @@ import eu.kanade.tachiyomi.util.system.dpToPxEnd
 import eu.kanade.tachiyomi.util.system.getResourceColor
 import eu.kanade.tachiyomi.util.system.launchUI
 import eu.kanade.tachiyomi.util.view.applyWindowInsetsForRootController
+import eu.kanade.tachiyomi.util.view.doOnApplyWindowInsets
 import eu.kanade.tachiyomi.util.view.getItemView
 import eu.kanade.tachiyomi.util.view.gone
 import eu.kanade.tachiyomi.util.view.hide
-import eu.kanade.tachiyomi.util.view.scrollViewWith
+import eu.kanade.tachiyomi.util.view.marginTop
 import eu.kanade.tachiyomi.util.view.setBackground
 import eu.kanade.tachiyomi.util.view.setOnQueryTextChangeListener
 import eu.kanade.tachiyomi.util.view.setStartTranslationX
@@ -68,6 +71,7 @@ import eu.kanade.tachiyomi.util.view.show
 import eu.kanade.tachiyomi.util.view.snack
 import eu.kanade.tachiyomi.util.view.updateLayoutParams
 import eu.kanade.tachiyomi.util.view.updatePaddingRelative
+import eu.kanade.tachiyomi.util.view.visibleIf
 import eu.kanade.tachiyomi.util.view.withFadeTransaction
 import kotlinx.android.synthetic.main.filter_bottom_sheet.*
 import kotlinx.android.synthetic.main.library_grid_recycler.*
@@ -142,7 +146,8 @@ class LibraryController(
     private var scrollAnim: ViewPropertyAnimator? = null
     private var alwaysShowScroller: Boolean = preferences.alwaysShowSeeker().getOrDefault()
     private var filterTooltip: ViewTooltip? = null
-
+    private var elevationAnim: ValueAnimator? = null
+    private var elevate = false
     override fun getTitle(): String? {
         return view?.context?.getString(R.string.library)
     }
@@ -150,6 +155,8 @@ class LibraryController(
     private var scrollListener = object : RecyclerView.OnScrollListener() {
         override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
             super.onScrolled(recyclerView, dx, dy)
+            val notAtTop = recycler.canScrollVertically(-1)
+            if (notAtTop != elevate) elevateFunc(notAtTop)
             val order = getCategoryOrder()
             if (filter_bottom_sheet.sheetBehavior?.state != BottomSheetBehavior.STATE_HIDDEN) {
                 scrollDistance += abs(dy)
@@ -161,6 +168,7 @@ class LibraryController(
             if (order != null && order != activeCategory && lastItem == null) {
                 preferences.lastUsedCategory().set(order)
                 activeCategory = order
+                setActiveCategory()
                 if (presenter.categories.size > 1 && dy != 0) {
                     val headerItem = getHeader() ?: return
                     val view = fast_scroller?.getChildAt(0) ?: return
@@ -226,6 +234,12 @@ class LibraryController(
         fast_scroller.setStartTranslationX(!alwaysShowScroller)
         fast_scroller.setBackground(!alwaysShowScroller)
 
+        show_all.isChecked = preferences.showAllCategories().get()
+        show_all.setOnCheckedChangeListener { _, isChecked ->
+            preferences.showAllCategories().set(isChecked)
+            presenter.getLibrary()
+        }
+
         adapter = LibraryCategoryAdapter(this)
         adapter.expandItemsAtStartUp()
         adapter.isRecursiveCollapse = true
@@ -243,7 +257,7 @@ class LibraryController(
         recycler.adapter = adapter
         fast_scroller.setupWithRecyclerView(recycler, { position ->
             val letter = adapter.getSectionText(position)
-            if (!singleCategory &&
+            if (!singleCategory && presenter.showAllCategories &&
                 !adapter.isHeader(adapter.getItem(position)) &&
                 position != adapter.itemCount - 1) null
             else if (letter != null) FastScrollItemIndicator.Text(letter)
@@ -287,8 +301,7 @@ class LibraryController(
                 appbar?.y = 0f
                 recycler.suppressLayout(true)
                 (recycler.layoutManager as LinearLayoutManager).scrollToPositionWithOffset(
-                    itemPosition,
+                    itemPosition, 0
-                    if (singleCategory) 0 else (if (itemPosition == 0) 0 else (-40).dpToPx)
                 )
                 recycler.suppressLayout(false)
             }
@@ -298,16 +311,43 @@ class LibraryController(
         val tv = TypedValue()
         activity!!.theme.resolveAttribute(R.attr.actionBarTintColor, tv, true)
         swipe_refresh.setStyle()
-        scrollViewWith(recycler, swipeRefreshLayout = swipe_refresh, afterInsets = { insets ->
+
+        recycler_cover.setOnClickListener {
+            showCategories(false)
+        }
+        category_recycler.onCategoryClicked = {
+            scrollToHeader(it)
+            showCategories(false)
+        }
+        swipe_refresh.setDistanceToTriggerSync(150.dpToPx)
+        val marginTop = category_layout.marginTop
+        recycler.doOnApplyWindowInsets { recyclerView, insets, _ ->
+            recyclerView.updateLayoutParams<ViewGroup.MarginLayoutParams> {
+                topMargin = marginTop + insets.systemWindowInsetTop
+            }
+            category_layout?.updateLayoutParams<ViewGroup.MarginLayoutParams> {
+                topMargin = marginTop + insets.systemWindowInsetTop
+            }
+            recycler_cover?.updateLayoutParams<ViewGroup.MarginLayoutParams> {
+                topMargin = marginTop + insets.systemWindowInsetTop
+            }
             fast_scroller?.updateLayoutParams<ViewGroup.MarginLayoutParams> {
                 topMargin = insets.systemWindowInsetTop
             }
-        })
+            swipe_refresh?.setProgressViewOffset(
+                true, (marginTop + insets.systemWindowInsetTop) + (-60).dpToPx, marginTop + insets.systemWindowInsetTop + 10.dpToPx
+            )
+        }
 
         swipe_refresh.setOnRefreshListener {
             swipe_refresh.isRefreshing = false
             if (!LibraryUpdateService.isRunning()) {
                 when {
+                    !presenter.showAllCategories -> {
+                        presenter.categories.find { it.id == presenter.currentCategory }?.let {
+                            updateLibrary(it)
+                        }
+                    }
                     presenter.allCategories.size <= 1 -> updateLibrary()
                     preferences.updateOnRefresh().getOrDefault() == -1 -> {
                         MaterialDialog(activity!!).title(R.string.what_should_update)
@@ -357,7 +397,7 @@ class LibraryController(
 
         presenter.onRestore()
         if (presenter.libraryItems.isNotEmpty()) {
-            onNextLibraryUpdate(presenter.libraryItems, true)
+            presenter.restoreLibrary()
         } else {
             recycler_layout.alpha = 0f
             presenter.getLibrary()
@@ -453,7 +493,13 @@ class LibraryController(
             presenter.getLibrary()
             DownloadService.callListeners()
             LibraryUpdateService.setListener(this)
-        } else closeTip()
+            recycler_cover.isClickable = false
+            recycler_cover.isFocusable = false
+            activity?.dropdown?.visibleIf(!singleCategory)
+        } else {
+            closeTip()
+            activity?.dropdown?.gone()
+        }
     }
 
     override fun onActivityResumed(activity: Activity) {
@@ -482,7 +528,7 @@ class LibraryController(
     }
 
     fun onNextLibraryUpdate(mangaMap: List<LibraryItem>, freshStart: Boolean = false) {
-        if (view == null) return
+        val view = view ?: return
         destroyActionModeIfNeeded()
         if (mangaMap.isNotEmpty()) {
             empty_view?.hide()
@@ -494,8 +540,12 @@ class LibraryController(
             )
         }
         adapter.setItems(mangaMap)
+        if (recycler.itemAnimator == null)
+        recycler.post {
+            recycler.itemAnimator = DefaultItemAnimator()
+        }
         singleCategory = presenter.categories.size <= 1
-
+        activity?.dropdown?.visibleIf(!singleCategory)
         progress.gone()
         if (!freshStart) {
             justStarted = false
@@ -506,15 +556,69 @@ class LibraryController(
             scrollToHeader(activeCategory)
             if (!alwaysShowScroller) {
                 fast_scroller?.show(false)
-                view?.post {
+                view.post {
                     scrollAnim = fast_scroller?.hide(2000)
                 }
             }
         }
         adapter.isLongPressDragEnabled = canDrag()
+        category_recycler.setCategories(presenter.categories)
+        setActiveCategory()
+        activity?.toolbar?.setOnClickListener {
+            val recycler = recycler ?: return@setOnClickListener
+            if (singleCategory) {
+                recycler.scrollToPosition(0)
+            } else {
+                showCategories(recycler.translationY == 0f)
+            }
+        }
+    }
+
+    private fun showCategories(show: Boolean) {
+        recycler_cover.isClickable = show
+        recycler_cover.isFocusable = show
+        val translateY = if (show) category_layout.height.toFloat() + 12f.dpToPx else 0f
+        recycler.animate().translationY(translateY).start()
+        recycler_cover.animate().translationY(translateY).start()
+        recycler_cover.animate().alpha(if (show) 0.75f else 0f).start()
+        if (show) {
+            elevateFunc(false)
+            activity?.dropdown?.setImageResource(R.drawable.ic_arrow_drop_up_24dp)
+        } else {
+            val notAtTop = recycler.canScrollVertically(-1)
+            if (notAtTop != elevate) elevateFunc(notAtTop)
+            activity?.dropdown?.setImageResource(R.drawable.ic_arrow_drop_down_24dp)
+        }
+    }
+
+    private fun elevateFunc(el: Boolean) {
+        elevate = el
+        elevationAnim?.cancel()
+        elevationAnim = ValueAnimator.ofFloat(
+            activity?.appbar?.elevation ?: 0f, if (el) 15f else 0f
+        )
+        elevationAnim?.addUpdateListener { valueAnimator ->
+            activity?.appbar?.elevation = valueAnimator.animatedValue as Float
+        }
+        elevationAnim?.start()
+    }
+
+    fun setActiveCategory() {
+        val currentCategory = presenter.categories.indexOfFirst {
+            if (presenter.showAllCategories) it.order == activeCategory else presenter.currentCategory == it.id
+        }
+        category_recycler.setCategories(currentCategory)
     }
 
     private fun scrollToHeader(pos: Int) {
+        if (!presenter.showAllCategories) {
+            recycler.itemAnimator = null
+            presenter.switchSection(pos)
+            activeCategory = pos
+            setActiveCategory()
+            recycler.scrollToPosition(0)
+            return
+        }
         val headerPosition = adapter.indexOf(pos)
         if (headerPosition > -1) {
             val appbar = activity?.appbar
@@ -523,7 +627,7 @@ class LibraryController(
                 view?.rootWindowInsets?.systemWindowInsetTop ?: 0
             ) ?: 0f).roundToInt() + 30.dpToPx
             (recycler.layoutManager as LinearLayoutManager).scrollToPositionWithOffset(
-                headerPosition, (if (headerPosition == 0) 0 else (-40).dpToPx) + appbarOffset
+                headerPosition, (if (headerPosition == 0) 0 else (-32).dpToPx) + appbarOffset
             )
             recycler.suppressLayout(false)
         }
@@ -815,6 +919,10 @@ class LibraryController(
     }
 
     override fun toggleCategoryVisibility(position: Int) {
+        if (!presenter.showAllCategories) {
+            showCategories(true)
+            return
+        }
         val catId = (adapter.getItem(position) as? LibraryHeaderItem)?.category?.id ?: return
         presenter.toggleCategoryVisibility(catId)
     }
@@ -842,6 +950,7 @@ class LibraryController(
         return items.all { adapter.isSelected(it) }
     }
 
+    //region sheet methods
     override fun showSheet() {
         closeTip()
         when {
@@ -875,6 +984,7 @@ class LibraryController(
         }
         return false
     }
+    //endregion
 
     //region Toolbar options methods
     override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryHeaderItem.kt

@@ -36,6 +36,7 @@ import eu.kanade.tachiyomi.util.view.invisible
 import eu.kanade.tachiyomi.util.view.updateLayoutParams
 import eu.kanade.tachiyomi.util.view.visInvisIf
 import eu.kanade.tachiyomi.util.view.visible
+import eu.kanade.tachiyomi.util.view.visibleIf
 import kotlinx.android.synthetic.main.library_category_header_item.*
 import uy.kohesive.injekt.Injekt
 import uy.kohesive.injekt.api.get
@@ -184,16 +185,16 @@ class LibraryHeaderItem(
                     updateButton.gone()
                 }
                 LibraryUpdateService.categoryInQueue(category.id) -> {
-                    expandImage.visible()
+                    expandImage.visibleIf(adapter.headerItems.size > 1)
                     checkboxImage.gone()
                     catProgress.visible()
                     updateButton.invisible()
                 }
                 else -> {
-                    expandImage.visible()
+                    expandImage.visibleIf(adapter.headerItems.size > 1)
                     catProgress.gone()
                     checkboxImage.gone()
-                    updateButton.visInvisIf(category.id ?: 0 > -1)
+                    updateButton.visInvisIf(category.id ?: 0 > -1 && adapter.headerItems.size > 1)
                 }
             }
         }

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt

@@ -60,7 +60,12 @@ class LibraryPresenter(
 
     /** List of all manga to update the */
     var libraryItems: List<LibraryItem> = emptyList()
+    private var sectionedLibraryItems: Map<Int, List<LibraryItem>> = emptyMap()
+    var currentCategory = -1
+        private set
     private var allLibraryItems: List<LibraryItem> = emptyList()
+    val showAllCategories
+        get() = preferences.showAllCategories().get()
 
     private var totalChapters: Map<Long, Int>? = null
 
@@ -92,16 +97,56 @@ class LibraryPresenter(
             mangaMap = applyFilters(mangaMap)
             mangaMap = applySort(mangaMap)
             val freshStart = libraryItems.isEmpty()
-            libraryItems = mangaMap
+            sectionLibrary(mangaMap, freshStart)
-            withContext(Dispatchers.Main) {
-                view.onNextLibraryUpdate(libraryItems, freshStart)
-            }
             withContext(Dispatchers.IO) {
                 setTotalChapters()
             }
         }
     }
 
+    fun getCurrentCategory() = categories.find { it.id == currentCategory }
+
+    fun switchSection(order: Int) {
+        preferences.lastUsedCategory().set(order)
+        val category = categories.find { it.order == order }?.id ?: return
+        currentCategory = category
+        view.onNextLibraryUpdate(sectionedLibraryItems[currentCategory] ?: emptyList())
+    }
+
+    fun restoreLibrary() {
+        val items = libraryItems
+        val show = showAllCategories || preferences.hideCategories().getOrDefault()
+        if (!show) {
+            sectionedLibraryItems = items.groupBy { it.manga.category }
+            if (currentCategory == -1) currentCategory = categories.find {
+                it.order == preferences.lastUsedCategory().getOrDefault()
+            }?.id ?: 0
+        }
+        view.onNextLibraryUpdate(
+            if (!show) sectionedLibraryItems[currentCategory]
+                ?: sectionedLibraryItems[categories.first().id] ?: emptyList()
+            else libraryItems, true
+        )
+    }
+
+    private suspend fun sectionLibrary(items: List<LibraryItem>, freshStart: Boolean = false) {
+        libraryItems = items
+        val show = showAllCategories || preferences.hideCategories().getOrDefault()
+        if (!show) {
+            sectionedLibraryItems = items.groupBy { it.manga.category }
+            if (currentCategory == -1) currentCategory = categories.find {
+                it.order == preferences.lastUsedCategory().getOrDefault()
+            }?.id ?: 0
+        }
+        withContext(Dispatchers.Main) {
+            view.onNextLibraryUpdate(
+                if (!show) sectionedLibraryItems[currentCategory]
+                ?: sectionedLibraryItems[categories.first().id] ?: emptyList()
+                else libraryItems, freshStart
+            )
+        }
+    }
+
     /**
      * Applies library filters to the given list of manga.
      *
@@ -402,6 +447,7 @@ class LibraryPresenter(
         val showCategories = !preferences.hideCategories().getOrDefault()
         var libraryManga = db.getLibraryMangas().executeAsBlocking()
         val seekPref = preferences.alwaysShowSeeker()
+        val showAll = showAllCategories
         if (!showCategories) libraryManga = libraryManga.distinctBy { it.id }
         val categoryAll = Category.createAll(
             context,
@@ -430,12 +476,13 @@ class LibraryPresenter(
         if (showCategories) {
             categories.forEach { category ->
                 val catId = category.id ?: return@forEach
-                if (catId > 0 && !categorySet.contains(catId) && catId !in categoriesHidden) {
+                if (catId > 0 && !categorySet.contains(catId) &&
+                    (catId !in categoriesHidden || !showAll)) {
                     val headerItem = headerItems[catId]
                     if (headerItem != null) items.add(
                         LibraryItem(LibraryManga.createBlank(catId), headerItem)
                     )
-                } else if (catId in categoriesHidden) {
+                } else if (catId in categoriesHidden && showAll) {
                     val mangaToRemove = items.filter { it.manga.category == catId }
                     val mergedTitle = mangaToRemove.joinToString("-") {
                         it.manga.title + "-" + it.manga.author
@@ -450,7 +497,7 @@ class LibraryPresenter(
         }
 
         categories.forEach {
-            it.isHidden = it.id in categoriesHidden
+            it.isHidden = it.id in categoriesHidden && showAll
         }
 
         this.allCategories = categories
@@ -476,10 +523,7 @@ class LibraryPresenter(
             var mangaMap = allLibraryItems
             mangaMap = applyFilters(mangaMap)
             mangaMap = applySort(mangaMap)
-            libraryItems = mangaMap
+            sectionLibrary(mangaMap)
-            withContext(Dispatchers.Main) {
-                view.onNextLibraryUpdate(libraryItems)
-            }
         }
     }
 
@@ -491,10 +535,7 @@ class LibraryPresenter(
             allLibraryItems = mangaMap
             val current = libraryItems
             setDownloadCount(current)
-            libraryItems = current
+            sectionLibrary(current)
-            withContext(Dispatchers.Main) {
-                view.onNextLibraryUpdate(libraryItems)
-            }
         }
     }
 
@@ -506,10 +547,7 @@ class LibraryPresenter(
             allLibraryItems = mangaMap
             val current = libraryItems
             setUnreadBadge(current)
-            libraryItems = current
+            sectionLibrary(current)
-            withContext(Dispatchers.Main) {
-                view.onNextLibraryUpdate(libraryItems)
-            }
         }
     }
 
@@ -518,10 +556,7 @@ class LibraryPresenter(
         scope.launch {
             var mangaMap = libraryItems
             mangaMap = applySort(mangaMap)
-            libraryItems = mangaMap
+            sectionLibrary(mangaMap)
-            withContext(Dispatchers.Main) {
-                view.onNextLibraryUpdate(libraryItems)
-            }
         }
     }
 

app/src/main/java/eu/kanade/tachiyomi/ui/library/category/CategoryItem.kt

@@ -0,0 +1,36 @@
+package eu.kanade.tachiyomi.ui.library.category
+
+import android.view.View
+import android.widget.TextView
+import com.mikepenz.fastadapter.FastAdapter
+import com.mikepenz.fastadapter.items.AbstractItem
+import eu.kanade.tachiyomi.R
+import eu.kanade.tachiyomi.data.database.models.Category
+
+class CategoryItem(val category: Category) :
+AbstractItem<CategoryItem.ViewHolder>() {
+
+    /** defines the type defining this item. must be unique. preferably an id */
+    override val type: Int = R.id.category_text
+
+    /** defines the layout which will be used for this item in the list */
+    override val layoutRes: Int = R.layout.catergory_text_view
+
+    override var identifier = category.id?.toLong() ?: -1L
+
+    override fun getViewHolder(v: View): ViewHolder {
+        return ViewHolder(v)
+    }
+
+    class ViewHolder(view: View) : FastAdapter.ViewHolder<CategoryItem>(view) {
+        val categoryTitle: TextView = view.findViewById(R.id.category_text)
+
+        override fun bindView(item: CategoryItem, payloads: List<Any>) {
+            categoryTitle.text = item.category.name
+        }
+
+        override fun unbindView(item: CategoryItem) {
+            categoryTitle.text = null
+        }
+    }
+}

app/src/main/java/eu/kanade/tachiyomi/ui/library/category/CategoryRecyclerView.kt

@@ -0,0 +1,70 @@
+package eu.kanade.tachiyomi.ui.library.category
+
+import android.content.Context
+import android.util.AttributeSet
+import android.view.ViewGroup
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import com.mikepenz.fastadapter.FastAdapter
+import com.mikepenz.fastadapter.adapters.ItemAdapter
+import com.mikepenz.fastadapter.listeners.OnBindViewHolderListenerImpl
+import eu.kanade.tachiyomi.R
+import eu.kanade.tachiyomi.data.database.models.Category
+import eu.kanade.tachiyomi.util.view.marginBottom
+import eu.kanade.tachiyomi.util.view.marginTop
+
+class CategoryRecyclerView @JvmOverloads constructor(
+    context: Context,
+    attrs: AttributeSet? = null
+) : RecyclerView(context, attrs) {
+
+    val manager = LinearLayoutManager(context)
+    private val fastAdapter: FastAdapter<CategoryItem>
+    var onCategoryClicked: (Int) -> Unit = { _ -> }
+    private val itemAdapter = ItemAdapter<CategoryItem>()
+    var selectedCategory: Int = 0
+
+    init {
+        fastAdapter = FastAdapter.with(itemAdapter)
+        layoutManager = manager
+        adapter = fastAdapter
+    }
+
+    fun setCategories(items: List<Category>) {
+        itemAdapter.set(items.map(::CategoryItem))
+        fastAdapter.onBindViewHolderListener = (object : OnBindViewHolderListenerImpl<CategoryItem>() {
+            override fun onBindViewHolder(
+                viewHolder: ViewHolder,
+                position: Int,
+                payloads: List<Any>
+            ) {
+                super.onBindViewHolder(viewHolder, position, payloads)
+                (viewHolder as? CategoryItem.ViewHolder)?.categoryTitle?.isSelected =
+                    selectedCategory == position
+            }
+        })
+        fastAdapter.onClickListener = { _, _, item, _ ->
+            onCategoryClicked(item.category.order)
+            true
+        }
+    }
+
+    fun setCategories(selected: Int) {
+        selectedCategory = selected
+        for (i in 0..manager.itemCount) {
+            (findViewHolderForAdapterPosition(i) as? CategoryItem.ViewHolder)?.categoryTitle?.isSelected =
+                selectedCategory == i
+        }
+    }
+
+    override fun onMeasure(widthSpec: Int, heightSpec: Int) {
+        val recyclerView = (parent.parent as ViewGroup).findViewById<RecyclerView>(R.id.recycler)
+        val top = recyclerView.marginTop
+        val bottom = recyclerView.marginBottom
+        val parent = recyclerView.measuredHeight - top - bottom
+        val heightS = if (parent > 0)
+            MeasureSpec.makeMeasureSpec(parent, MeasureSpec.AT_MOST)
+        else heightSpec
+        super.onMeasure(widthSpec, heightS)
+    }
+}

app/src/main/res/drawable/ic_arrow_drop_down_24dp.xml

@@ -0,0 +1,5 @@
+<vector android:height="24dp" android:tint="#FFFFFF"
+    android:viewportHeight="24.0" android:viewportWidth="24.0"
+    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="#FF000000" android:pathData="M7,10l5,5 5,-5z"/>
+</vector>

app/src/main/res/drawable/ic_arrow_drop_up_24dp.xml

@@ -0,0 +1,5 @@
+<vector android:height="24dp" android:tint="#FFFFFF"
+    android:viewportHeight="24.0" android:viewportWidth="24.0"
+    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="#FF000000" android:pathData="M7,14l5,-5 5,5z"/>
+</vector>

app/src/main/res/drawable/list_item_selector.xml

@@ -15,7 +15,7 @@
             </item>
 
             <item android:id="@android:id/mask">
-                <color android:color="@android:color/transparent" />
+                <color android:color="?android:colorBackground" />
             </item>
         </selector>
     </item>

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

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:background="@drawable/list_item_selector">
+
+    <com.google.android.material.textview.MaterialTextView
+        android:id="@+id/category_text"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:background="@drawable/list_item_selector"
+        android:paddingStart="12dp"
+        android:paddingTop="8dp"
+        android:paddingEnd="0dp"
+        android:paddingBottom="8dp"
+        tools:text="@string/categories"
+        android:textAppearance="@style/TextAppearance.MaterialComponents.Headline6"
+        android:textSize="16sp" />
+</FrameLayout>

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

@@ -8,6 +8,14 @@
     android:background="@drawable/list_item_selector"
     android:gravity="center_vertical">
 
+    <Space
+        android:id="@+id/start_space"
+        android:layout_width="6dp"
+        app:layout_constraintBottom_toBottomOf="@+id/category_title"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="@+id/category_title"
+        android:layout_height="1dp"/>
+
     <ImageView
         android:id="@+id/checkbox"
         android:layout_width="wrap_content"
@@ -42,7 +50,7 @@
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         app:barrierDirection="right"
-        app:constraint_referenced_ids="collapse_arrow,checkbox"
+        app:constraint_referenced_ids="start_space,collapse_arrow,checkbox"
         />
 
     <TextView

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

@@ -7,4 +7,5 @@
     android:layout_height="match_parent"
     android:columnWidth="140dp"
     android:clipToPadding="false"
-    tools:listitem="@layout/manga_grid_item" />
+    android:background="@drawable/bottom_sheet_rounded_background"
+    tools:listitem="@layout/manga_grid_item"/>

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

@@ -22,8 +22,37 @@
             android:layout_width="match_parent"
             android:layout_height="match_parent">
 
+            <LinearLayout
+                android:id="@+id/category_layout"
+                android:layout_width="match_parent"
+                android:layout_marginTop="?actionBarSize"
+                android:orientation="vertical"
+                android:gravity="top"
+                android:layout_height="wrap_content" >
+                <com.google.android.material.checkbox.MaterialCheckBox
+                    android:id="@+id/show_all"
+                    android:layout_marginStart="6dp"
+                    android:layout_width="match_parent"
+                    android:layout_height="wrap_content"
+                    android:text="@string/show_all"/>
+
+                <eu.kanade.tachiyomi.ui.library.category.CategoryRecyclerView
+                    android:id="@+id/category_recycler"
+                    android:layout_width="match_parent"
+                    android:layout_height="wrap_content" />
+            </LinearLayout>
+
             <include layout="@layout/library_grid_recycler" />
+
+            <View
+                android:id="@+id/recycler_cover"
+                android:layout_marginTop="?actionBarSize"
+                android:alpha="0"
+                android:layout_width="match_parent"
+                android:layout_height="match_parent"
+                android:background="?android:colorBackground"/>
         </FrameLayout>
+
     </androidx.swiperefreshlayout.widget.SwipeRefreshLayout>
 
     <androidx.constraintlayout.widget.ConstraintLayout

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

@@ -55,6 +55,16 @@
                     android:textColor="?actionBarTintColor"
                     android:textSize="20sp"
                     tools:text="Title Text" />
+
+                <ImageView
+                    android:id="@+id/dropdown"
+                    android:visibility="gone"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:layout_gravity="center"
+                    android:layout_marginStart="4dp"
+                    android:src="@drawable/ic_arrow_drop_down_24dp"
+                    android:tint="?actionBarTintColor" />
             </LinearLayout>
         </eu.kanade.tachiyomi.ui.base.CenteredToolbar>
     </com.google.android.material.appbar.AppBarLayout>

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

@@ -4,7 +4,6 @@
     xmlns:tools="http://schemas.android.com/tools"
     android:id="@+id/manga_layout"
     android:layout_width="match_parent"
-    tools:background="?android:attr/colorBackground"
     android:layout_height="wrap_content"
     android:layout_gravity="bottom">
 

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

@@ -9,5 +9,4 @@
     android:columnWidth="120dp"
     android:clipToPadding="false"
     tools:listitem="@layout/manga_grid_item"
-    android:background="?android:colorBackground"
     xmlns:app="http://schemas.android.com/apk/res-auto" />