Library views recycling

app/src/main/java/eu/kanade/tachiyomi/ui/base/adapter/FlexibleViewHolder.kt

@@ -27,7 +27,7 @@ abstract class FlexibleViewHolder(view: View,
         return true
     }
 
-    protected fun toggleActivation() {
+    fun toggleActivation() {
         itemView.isActivated = adapter.isSelected(adapterPosition)
     }
 

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

@@ -1,22 +1,23 @@
 package eu.kanade.tachiyomi.ui.library
 
-import android.support.v4.app.Fragment
+import android.view.View
-import android.support.v4.app.FragmentManager
+import android.view.ViewGroup
+import eu.kanade.tachiyomi.R
 import eu.kanade.tachiyomi.data.database.models.Category
-import eu.kanade.tachiyomi.ui.base.adapter.SmartFragmentStatePagerAdapter
+import eu.kanade.tachiyomi.util.inflate
+import eu.kanade.tachiyomi.widget.RecyclerViewPagerAdapter
 
 /**
  * This adapter stores the categories from the library, used with a ViewPager.
  *
- * @param fm the fragment manager.
  * @constructor creates an instance of the adapter.
  */
-class LibraryAdapter(fm: FragmentManager) : SmartFragmentStatePagerAdapter(fm) {
+class LibraryAdapter(private val fragment: LibraryFragment) : RecyclerViewPagerAdapter() {
 
     /**
      * The categories to bind in the adapter.
      */
-    var categories: List<Category>? = null
+    var categories: List<Category> = emptyList()
         // This setter helps to not refresh the adapter if the reference to the list doesn't change.
         set(value) {
             if (field !== value) {
@@ -26,13 +27,34 @@ class LibraryAdapter(fm: FragmentManager) : SmartFragmentStatePagerAdapter(fm) {
         }
 
     /**
-     * Creates a new fragment for the given position when it's called.
+     * Creates a new view for this adapter.
      *
-     * @param position the position to instantiate.
+     * @return a new view.
-     * @return a fragment for the given position.
      */
-    override fun getItem(position: Int): Fragment {
+    override fun createView(container: ViewGroup): View {
-        return LibraryCategoryFragment.newInstance(position)
+        val view = container.inflate(R.layout.item_library_category) as LibraryCategoryFragment
+        view.onCreate(fragment)
+        return view
+    }
+
+    /**
+     * Binds a view with a position.
+     *
+     * @param view the view to bind.
+     * @param position the position in the adapter.
+     */
+    override fun bindView(view: View, position: Int) {
+        (view as LibraryCategoryFragment).onBind(categories[position])
+    }
+
+    /**
+     * Recycles a view.
+     *
+     * @param view the view to recycle.
+     * @param position the position in the adapter.
+     */
+    override fun recycleView(view: View, position: Int) {
+        (view as LibraryCategoryFragment).onRecycle()
     }
 
     /**
@@ -41,7 +63,7 @@ class LibraryAdapter(fm: FragmentManager) : SmartFragmentStatePagerAdapter(fm) {
      * @return the number of categories or 0 if the list is null.
      */
     override fun getCount(): Int {
-        return categories?.size ?: 0
+        return categories.size
     }
 
     /**
@@ -51,28 +73,7 @@ class LibraryAdapter(fm: FragmentManager) : SmartFragmentStatePagerAdapter(fm) {
      * @return the title to display.
      */
     override fun getPageTitle(position: Int): CharSequence {
-        return categories!![position].name
+        return categories[position].name
-    }
-
-    /**
-     * Method to enable or disable the action mode (multiple selection) for all the instantiated
-     * fragments.
-     *
-     * @param mode the mode to set.
-     */
-    fun setSelectionMode(mode: Int) {
-        for (fragment in getRegisteredFragments()) {
-            (fragment as LibraryCategoryFragment).setSelectionMode(mode)
-        }
-    }
-
-    /**
-     * Notifies the adapters in all the registered fragments to refresh their content.
-     */
-    fun refreshRegisteredAdapters() {
-        for (fragment in getRegisteredFragments()) {
-            (fragment as LibraryCategoryFragment).adapter.notifyDataSetChanged()
-        }
     }
 
 }

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

@@ -84,7 +84,7 @@ class LibraryCategoryAdapter(val fragment: LibraryCategoryFragment) :
      * @return a new view holder for a manga.
      */
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): LibraryHolder {
-        //depending on preferences, display a list or display a grid
+        // Depending on preferences, display a list or display a grid
         if (parent is AutofitRecyclerView) {
             val view = parent.inflate(R.layout.item_catalogue_grid).apply {
                 val coverHeight = parent.itemWidth / 3 * 4
@@ -96,7 +96,6 @@ class LibraryCategoryAdapter(val fragment: LibraryCategoryFragment) :
             val view = parent.inflate(R.layout.item_library_list)
             return LibraryListHolder(view, this, fragment)
         }
-
     }
 
     /**
@@ -109,8 +108,17 @@ class LibraryCategoryAdapter(val fragment: LibraryCategoryFragment) :
         val manga = getItem(position)
 
         holder.onSetValues(manga)
-        //When user scrolls this bind the correct selection status
+        // When user scrolls this bind the correct selection status
         holder.itemView.isActivated = isSelected(position)
     }
 
+    /**
+     * Returns the position in the adapter for the given manga.
+     *
+     * @param manga the manga to find.
+     */
+    fun indexOf(manga: Manga): Int {
+        return mangas.orEmpty().indexOfFirst { it.id == manga.id }
+    }
+
 }

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

@@ -1,24 +1,23 @@
 package eu.kanade.tachiyomi.ui.library
 
-import android.os.Bundle
+import android.content.Context
 import android.support.v7.widget.LinearLayoutManager
 import android.support.v7.widget.RecyclerView
-import android.view.LayoutInflater
+import android.util.AttributeSet
-import android.view.View
+import android.widget.FrameLayout
-import android.view.ViewGroup
 import eu.davidea.flexibleadapter.FlexibleAdapter
 import eu.kanade.tachiyomi.R
+import eu.kanade.tachiyomi.data.database.models.Category
 import eu.kanade.tachiyomi.data.database.models.Manga
 import eu.kanade.tachiyomi.data.library.LibraryUpdateService
 import eu.kanade.tachiyomi.data.preference.PreferencesHelper
 import eu.kanade.tachiyomi.data.preference.getOrDefault
 import eu.kanade.tachiyomi.ui.base.adapter.FlexibleViewHolder
-import eu.kanade.tachiyomi.ui.base.fragment.BaseFragment
 import eu.kanade.tachiyomi.ui.manga.MangaActivity
 import eu.kanade.tachiyomi.util.inflate
 import eu.kanade.tachiyomi.util.toast
 import eu.kanade.tachiyomi.widget.AutofitRecyclerView
-import kotlinx.android.synthetic.main.fragment_library_category.*
+import kotlinx.android.synthetic.main.item_library_category.view.*
 import rx.Subscription
 import uy.kohesive.injekt.injectLazy
 
@@ -26,23 +25,33 @@ import uy.kohesive.injekt.injectLazy
  * Fragment containing the library manga for a certain category.
  * Uses R.layout.fragment_library_category.
  */
-class LibraryCategoryFragment : BaseFragment(), FlexibleViewHolder.OnListItemClickListener {
+class LibraryCategoryFragment @JvmOverloads constructor(context: Context, attrs: AttributeSet? = null)
+: FrameLayout(context, attrs), FlexibleViewHolder.OnListItemClickListener {
 
     /**
      * Preferences.
      */
-    val preferences: PreferencesHelper by injectLazy()
+    private val preferences: PreferencesHelper by injectLazy()
+
+    /**
+     * The fragment containing this view.
+     */
+    private lateinit var fragment: LibraryFragment
+
+    /**
+     * Category for this view.
+     */
+    private lateinit var category: Category
+
+    /**
+     * Recycler view of the list of manga.
+     */
+    private lateinit var recycler: RecyclerView
 
     /**
      * Adapter to hold the manga in this category.
      */
-    lateinit var adapter: LibraryCategoryAdapter
+    private lateinit var adapter: LibraryCategoryAdapter
-        private set
-
-    /**
-     * Position in the adapter from [LibraryAdapter].
-     */
-    private var position: Int = 0
 
     /**
      * Subscription for the library manga.
@@ -54,69 +63,30 @@ class LibraryCategoryFragment : BaseFragment(), FlexibleViewHolder.OnListItemCli
      */
     private var searchSubscription: Subscription? = null
 
-    companion object {
+    /**
-        /**
+     * Subscription of the library selections.
-         * Key to save and restore [position] from a [Bundle].
+     */
-         */
+    private var selectionSubscription: Subscription? = null
-        const val POSITION_KEY = "position_key"
 
-        /**
+    fun onCreate(fragment: LibraryFragment) {
-         * Creates a new instance of this class.
+        this.fragment = fragment
-         *
-         * @param position the position in the adapter from [LibraryAdapter].
-         * @return a new instance of [LibraryCategoryFragment].
-         */
-        fun newInstance(position: Int): LibraryCategoryFragment {
-            val fragment = LibraryCategoryFragment()
-            fragment.position = position
 
-            return fragment
+        recycler = if (preferences.libraryAsList().getOrDefault()) {
-        }
-    }
-
-    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedState: Bundle?): View? {
-        return inflater.inflate(R.layout.fragment_library_category, container, false)
-    }
-
-    override fun onViewCreated(view: View, savedState: Bundle?) {
-        adapter = LibraryCategoryAdapter(this)
-
-        val recycler = if (preferences.libraryAsList().getOrDefault()) {
             (swipe_refresh.inflate(R.layout.library_list_recycler) as RecyclerView).apply {
                 layoutManager = LinearLayoutManager(context)
             }
         } else {
             (swipe_refresh.inflate(R.layout.library_grid_recycler) as AutofitRecyclerView).apply {
-                spanCount = libraryFragment.mangaPerRow
+                spanCount = fragment.mangaPerRow
             }
         }
 
-        // This crashes when opening a manga after changing categories, but then viewholders aren't
+        adapter = LibraryCategoryAdapter(this)
-        // recycled between pages. It may be fixed if this fragment is replaced with a custom view.
+
-        //(recycler.layoutManager as LinearLayoutManager).recycleChildrenOnDetach = true
-        //recycler.recycledViewPool = libraryFragment.pool
         recycler.setHasFixedSize(true)
         recycler.adapter = adapter
         swipe_refresh.addView(recycler)
 
-        if (libraryFragment.actionMode != null) {
-            setSelectionMode(FlexibleAdapter.MODE_MULTI)
-        }
-
-        searchSubscription = libraryPresenter.searchSubject.subscribe { text ->
-            adapter.searchText = text
-            adapter.updateDataSet()
-        }
-
-        if (savedState != null) {
-            position = savedState.getInt(POSITION_KEY)
-            adapter.onRestoreInstanceState(savedState)
-
-            if (adapter.mode == FlexibleAdapter.MODE_SINGLE) {
-                adapter.clearSelection()
-            }
-        }
-
         recycler.addOnScrollListener(object : RecyclerView.OnScrollListener() {
             override fun onScrollStateChanged(recycler: RecyclerView, newState: Int) {
                 // Disable swipe refresh when view is not at the top
@@ -130,36 +100,47 @@ class LibraryCategoryFragment : BaseFragment(), FlexibleViewHolder.OnListItemCli
         swipe_refresh.setDistanceToTriggerSync((2 * 64 * resources.displayMetrics.density).toInt())
         swipe_refresh.setOnRefreshListener {
             if (!LibraryUpdateService.isRunning(context)) {
-                libraryPresenter.categories.getOrNull(position)?.let {
+                LibraryUpdateService.start(context, true, category)
-                    LibraryUpdateService.start(context, true, it)
+                context.toast(R.string.updating_category)
-                    context.toast(R.string.updating_category)
-                }
             }
             // It can be a very long operation, so we disable swipe refresh and show a toast.
             swipe_refresh.isRefreshing = false
         }
     }
 
-    override fun onDestroyView() {
+    fun onBind(category: Category) {
-        searchSubscription?.unsubscribe()
+        this.category = category
-        super.onDestroyView()
-    }
 
-    override fun onResume() {
+        val presenter = fragment.presenter
-        super.onResume()
+
-        libraryMangaSubscription = libraryPresenter.libraryMangaSubject
+        searchSubscription = presenter.searchSubject.subscribe { text ->
+            adapter.searchText = text
+            adapter.updateDataSet()
+        }
+
+        adapter.mode = if (presenter.selectedMangas.isNotEmpty()) {
+            FlexibleAdapter.MODE_MULTI
+        } else {
+            FlexibleAdapter.MODE_SINGLE
+        }
+
+        libraryMangaSubscription = presenter.libraryMangaSubject
                 .subscribe { onNextLibraryManga(it) }
+
+        selectionSubscription = presenter.selectionSubject
+                .subscribe { onSelectionChanged(it) }
     }
 
-    override fun onPause() {
+    fun onRecycle() {
+        adapter.setItems(emptyList())
+        adapter.clearSelection()
+    }
+
+    override fun onDetachedFromWindow() {
+        searchSubscription?.unsubscribe()
         libraryMangaSubscription?.unsubscribe()
-        super.onPause()
+        selectionSubscription?.unsubscribe()
-    }
+        super.onDetachedFromWindow()
-
-    override fun onSaveInstanceState(outState: Bundle) {
-        outState.putInt(POSITION_KEY, position)
-        adapter.onSaveInstanceState(outState)
-        super.onSaveInstanceState(outState)
     }
 
     /**
@@ -169,17 +150,61 @@ class LibraryCategoryFragment : BaseFragment(), FlexibleViewHolder.OnListItemCli
      * @param event the event received.
      */
     fun onNextLibraryManga(event: LibraryMangaEvent) {
-        // Get the categories from the parent fragment.
-        val categories = libraryFragment.adapter.categories ?: return
-
-        // When a category is deleted, the index can be greater than the number of categories.
-        if (position >= categories.size) return
-
         // Get the manga list for this category.
-        val mangaForCategory = event.getMangaForCategory(categories[position]) ?: emptyList()
+        val mangaForCategory = event.getMangaForCategory(category).orEmpty()
 
         // Update the category with its manga.
         adapter.setItems(mangaForCategory)
+
+        if (adapter.mode == FlexibleAdapter.MODE_MULTI) {
+            fragment.presenter.selectedMangas.forEach { manga ->
+                val position = adapter.indexOf(manga)
+                if (position != -1 && !adapter.isSelected(position)) {
+                    adapter.toggleSelection(position)
+                    (recycler.findViewHolderForItemId(manga.id!!) as? LibraryHolder)?.toggleActivation()
+                }
+            }
+        }
+    }
+
+    /**
+     * Subscribe to [LibrarySelectionEvent]. When an event is received, it updates the selection
+     * depending on the type of event received.
+     *
+     * @param event the selection event received.
+     */
+    private fun onSelectionChanged(event: LibrarySelectionEvent) {
+        when (event) {
+            is LibrarySelectionEvent.Selected -> {
+                if (adapter.mode != FlexibleAdapter.MODE_MULTI) {
+                    adapter.mode = FlexibleAdapter.MODE_MULTI
+                }
+                findAndToggleSelection(event.manga)
+            }
+            is LibrarySelectionEvent.Unselected -> {
+                findAndToggleSelection(event.manga)
+                if (fragment.presenter.selectedMangas.isEmpty()) {
+                    adapter.mode = FlexibleAdapter.MODE_SINGLE
+                }
+            }
+            is LibrarySelectionEvent.Cleared -> {
+                adapter.mode = FlexibleAdapter.MODE_SINGLE
+                adapter.clearSelection()
+            }
+        }
+    }
+
+    /**
+     * Toggles the selection for the given manga and updates the view if needed.
+     *
+     * @param manga the manga to toggle.
+     */
+    private fun findAndToggleSelection(manga: Manga) {
+        val position = adapter.indexOf(manga)
+        if (position != -1) {
+            adapter.toggleSelection(position)
+            (recycler.findViewHolderForItemId(manga.id!!) as? LibraryHolder)?.toggleActivation()
+        }
     }
 
     /**
@@ -191,7 +216,7 @@ class LibraryCategoryFragment : BaseFragment(), FlexibleViewHolder.OnListItemCli
     override fun onListItemClick(position: Int): Boolean {
         // If the action mode is created and the position is valid, toggle the selection.
         val item = adapter.getItem(position) ?: return false
-        if (libraryFragment.actionMode != null) {
+        if (adapter.mode == FlexibleAdapter.MODE_MULTI) {
             toggleSelection(position)
             return true
         } else {
@@ -206,7 +231,7 @@ class LibraryCategoryFragment : BaseFragment(), FlexibleViewHolder.OnListItemCli
      * @param position the position of the element clicked.
      */
     override fun onListItemLongClick(position: Int) {
-        libraryFragment.createActionModeIfNeeded()
+        fragment.createActionModeIfNeeded()
         toggleSelection(position)
     }
 
@@ -217,63 +242,24 @@ class LibraryCategoryFragment : BaseFragment(), FlexibleViewHolder.OnListItemCli
      */
     private fun openManga(manga: Manga) {
         // Notify the presenter a manga is being opened.
-        libraryPresenter.onOpenManga()
+        fragment.presenter.onOpenManga()
 
         // Create a new activity with the manga.
         val intent = MangaActivity.newIntent(context, manga)
-        startActivity(intent)
+        fragment.startActivity(intent)
     }
 
 
     /**
-     * Toggles the selection for a manga.
+     * Tells the presenter to toggle the selection for the given position.
      *
      * @param position the position to toggle.
      */
     private fun toggleSelection(position: Int) {
-        val library = libraryFragment
+        val manga = adapter.getItem(position) ?: return
 
-        // Toggle the selection.
+        fragment.presenter.setSelection(manga, !adapter.isSelected(position))
-        adapter.toggleSelection(position, false)
+        fragment.invalidateActionMode()
-
-        // Notify the selection to the presenter.
-        library.presenter.setSelection(adapter.getItem(position), adapter.isSelected(position))
-
-        // Get the selected count.
-        val count = library.presenter.selectedMangas.size
-        if (count == 0) {
-            // Destroy action mode if there are no items selected.
-            library.destroyActionModeIfNeeded()
-        } else {
-            // Update action mode with the new selection.
-            library.setContextTitle(count)
-            library.setVisibilityOfCoverEdit(count)
-            library.invalidateActionMode()
-        }
     }
 
-    /**
-     * Sets the mode for the adapter.
-     *
-     * @param mode the mode to set. It should be MODE_SINGLE or MODE_MULTI.
-     */
-    fun setSelectionMode(mode: Int) {
-        adapter.mode = mode
-        if (mode == FlexibleAdapter.MODE_SINGLE) {
-            adapter.clearSelection()
-        }
-    }
-
-    /**
-     * Property to get the library fragment.
-     */
-    private val libraryFragment: LibraryFragment
-        get() = parentFragment as LibraryFragment
-
-    /**
-     * Property to get the library presenter.
-     */
-    private val libraryPresenter: LibraryPresenter
-        get() = libraryFragment.presenter
-
 }

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

@@ -11,7 +11,6 @@ import android.support.v7.widget.SearchView
 import android.view.*
 import com.afollestad.materialdialogs.MaterialDialog
 import com.f2prateek.rx.preferences.Preference
-import eu.davidea.flexibleadapter.FlexibleAdapter
 import eu.kanade.tachiyomi.R
 import eu.kanade.tachiyomi.data.database.models.Category
 import eu.kanade.tachiyomi.data.database.models.Manga
@@ -26,6 +25,7 @@ import kotlinx.android.synthetic.main.activity_main.*
 import kotlinx.android.synthetic.main.fragment_library.*
 import nucleus.factory.RequiresPresenter
 import rx.Subscription
+import timber.log.Timber
 import uy.kohesive.injekt.injectLazy
 import java.io.IOException
 
@@ -66,8 +66,7 @@ class LibraryFragment : BaseRxFragment<LibraryPresenter>(), ActionMode.Callback
     /**
      * Action mode for manga selection.
      */
-    var actionMode: ActionMode? = null
+    private var actionMode: ActionMode? = null
-        private set
 
     /**
      * Selected manga for editing its cover.
@@ -91,14 +90,8 @@ class LibraryFragment : BaseRxFragment<LibraryPresenter>(), ActionMode.Callback
         private set
 
     /**
-     * A pool to share view holders between all the registered categories (fragments).
+     * Subscription for the number of manga per row.
      */
-    // TODO find out why this breaks sometimes
-//    var pool = RecyclerView.RecycledViewPool().apply { setMaxRecycledViews(0, 20) }
-//        private set(value) {
-//            field = value.apply { setMaxRecycledViews(0, 20) }
-//        }
-
     private var numColumnsSubscription: Subscription? = null
 
     companion object {
@@ -141,7 +134,7 @@ class LibraryFragment : BaseRxFragment<LibraryPresenter>(), ActionMode.Callback
     override fun onViewCreated(view: View, savedState: Bundle?) {
         setToolbarTitle(getString(R.string.label_library))
 
-        adapter = LibraryAdapter(childFragmentManager)
+        adapter = LibraryAdapter(this)
         view_pager.adapter = adapter
         view_pager.addOnPageChangeListener(object : ViewPager.SimpleOnPageChangeListener() {
             override fun onPageSelected(position: Int) {
@@ -154,6 +147,9 @@ class LibraryFragment : BaseRxFragment<LibraryPresenter>(), ActionMode.Callback
             activeCategory = savedState.getInt(CATEGORY_KEY)
             query = savedState.getString(QUERY_KEY)
             presenter.searchSubject.onNext(query)
+            if (presenter.selectedMangas.isNotEmpty()) {
+                createActionModeIfNeeded()
+            }
         } else {
             activeCategory = preferences.lastUsedCategory().getOrDefault()
         }
@@ -261,8 +257,7 @@ class LibraryFragment : BaseRxFragment<LibraryPresenter>(), ActionMode.Callback
      * Applies filter change
      */
     private fun onFilterCheckboxChanged() {
-        presenter.updateLibrary()
+        presenter.resubscribeLibrary()
-        adapter.refreshRegisteredAdapters()
         activity.supportInvalidateOptionsMenu()
     }
 
@@ -278,11 +273,11 @@ class LibraryFragment : BaseRxFragment<LibraryPresenter>(), ActionMode.Callback
      * Reattaches the adapter to the view pager to recreate fragments
      */
     private fun reattachAdapter() {
-//        pool.clear()
-//        pool = RecyclerView.RecycledViewPool()
         val position = view_pager.currentItem
+        adapter.recycle = false
         view_pager.adapter = adapter
         view_pager.currentItem = position
+        adapter.recycle = true
     }
 
     /**
@@ -323,7 +318,7 @@ class LibraryFragment : BaseRxFragment<LibraryPresenter>(), ActionMode.Callback
                 R.string.information_empty_library, R.drawable.ic_book_black_128dp)
 
         // Get the current active category.
-        val activeCat = if (adapter.categories != null) view_pager.currentItem else activeCategory
+        val activeCat = if (adapter.categories.isNotEmpty()) view_pager.currentItem else activeCategory
 
         // Set the categories
         adapter.categories = categories
@@ -339,31 +334,42 @@ class LibraryFragment : BaseRxFragment<LibraryPresenter>(), ActionMode.Callback
     }
 
     /**
-     * Sets the title of the action mode.
+     * Creates the action mode if it's not created already.
-     *
-     * @param count the number of items selected.
      */
-    fun setContextTitle(count: Int) {
+    fun createActionModeIfNeeded() {
-        actionMode?.title = getString(R.string.label_selected, count)
+        if (actionMode == null) {
+            actionMode = activity.startSupportActionMode(this)
+        }
     }
 
     /**
-     * Sets the visibility of the edit cover item.
+     * Destroys the action mode.
-     *
-     * @param count the number of items selected.
      */
-    fun setVisibilityOfCoverEdit(count: Int) {
+    fun destroyActionModeIfNeeded() {
-        // If count = 1 display edit button
+        actionMode?.finish()
-        actionMode?.menu?.findItem(R.id.action_edit_cover)?.isVisible = count == 1
+    }
+
+    /**
+     * Invalidates the action mode, forcing it to refresh its content.
+     */
+    fun invalidateActionMode() {
+        actionMode?.invalidate()
     }
 
     override fun onCreateActionMode(mode: ActionMode, menu: Menu): Boolean {
         mode.menuInflater.inflate(R.menu.library_selection, menu)
-        adapter.setSelectionMode(FlexibleAdapter.MODE_MULTI)
         return true
     }
 
     override fun onPrepareActionMode(mode: ActionMode, menu: Menu): Boolean {
+        val count = presenter.selectedMangas.size
+        if (count == 0) {
+            // Destroy action mode if there are no items selected.
+            destroyActionModeIfNeeded()
+        } else {
+            mode.title = getString(R.string.label_selected, count)
+            menu.findItem(R.id.action_edit_cover)?.isVisible = count == 1
+        }
         return false
     }
 
@@ -381,18 +387,10 @@ class LibraryFragment : BaseRxFragment<LibraryPresenter>(), ActionMode.Callback
     }
 
     override fun onDestroyActionMode(mode: ActionMode) {
-        adapter.setSelectionMode(FlexibleAdapter.MODE_SINGLE)
+        presenter.clearSelections()
-        presenter.selectedMangas.clear()
         actionMode = null
     }
 
-    /**
-     * Destroys the action mode.
-     */
-    fun destroyActionModeIfNeeded() {
-        actionMode?.finish()
-    }
-
     /**
      * Changes the cover for the selected manga.
      *
@@ -422,14 +420,14 @@ class LibraryFragment : BaseRxFragment<LibraryPresenter>(), ActionMode.Callback
                     context.contentResolver.openInputStream(data.data).use {
                         // Update cover to selected file, show error if something went wrong
                         if (presenter.editCoverWithStream(it, manga)) {
-                            adapter.refreshRegisteredAdapters()
+                            // TODO refresh cover
                         } else {
                             context.toast(R.string.notification_manga_update_failed)
                         }
                     }
-                } catch (e: IOException) {
+                } catch (error: IOException) {
                     context.toast(R.string.notification_manga_update_failed)
-                    e.printStackTrace()
+                    Timber.e(error, error.message)
                 }
             }
 
@@ -476,20 +474,4 @@ class LibraryFragment : BaseRxFragment<LibraryPresenter>(), ActionMode.Callback
                 .show()
     }
 
-    /**
-     * Creates the action mode if it's not created already.
-     */
-    fun createActionModeIfNeeded() {
-        if (actionMode == null) {
-            actionMode = activity.startSupportActionMode(this)
-        }
-    }
-
-    /**
-     * Invalidates the action mode, forcing it to refresh its content.
-     */
-    fun invalidateActionMode() {
-        actionMode?.invalidate()
-    }
-
 }

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

@@ -16,6 +16,7 @@ import rx.Observable
 import rx.android.schedulers.AndroidSchedulers
 import rx.schedulers.Schedulers
 import rx.subjects.BehaviorSubject
+import rx.subjects.PublishSubject
 import uy.kohesive.injekt.injectLazy
 import java.io.IOException
 import java.io.InputStream
@@ -29,22 +30,27 @@ class LibraryPresenter : BasePresenter<LibraryFragment>() {
     /**
      * Categories of the library.
      */
-    lateinit var categories: List<Category>
+    var categories: List<Category> = emptyList()
 
     /**
      * Currently selected manga.
      */
-    var selectedMangas = mutableListOf<Manga>()
+    val selectedMangas = mutableListOf<Manga>()
 
     /**
      * Search query of the library.
      */
-    val searchSubject: BehaviorSubject<String> = BehaviorSubject.create<String>()
+    val searchSubject: BehaviorSubject<String> = BehaviorSubject.create()
 
     /**
      * Subject to notify the library's viewpager for updates.
      */
-    val libraryMangaSubject: BehaviorSubject<LibraryMangaEvent> = BehaviorSubject.create<LibraryMangaEvent>()
+    val libraryMangaSubject: BehaviorSubject<LibraryMangaEvent> = BehaviorSubject.create()
+
+    /**
+     * Subject to notify the UI of selection updates.
+     */
+    val selectionSubject: PublishSubject<LibrarySelectionEvent> = PublishSubject.create()
 
     /**
      * Database.
@@ -149,7 +155,7 @@ class LibraryPresenter : BasePresenter<LibraryFragment>() {
     /**
      * Resubscribes to library.
      */
-    fun updateLibrary() {
+    fun resubscribeLibrary() {
         start(GET_LIBRARY)
     }
 
@@ -219,11 +225,21 @@ class LibraryPresenter : BasePresenter<LibraryFragment>() {
     fun setSelection(manga: Manga, selected: Boolean) {
         if (selected) {
             selectedMangas.add(manga)
+            selectionSubject.onNext(LibrarySelectionEvent.Selected(manga))
         } else {
             selectedMangas.remove(manga)
+            selectionSubject.onNext(LibrarySelectionEvent.Unselected(manga))
         }
     }
 
+    /**
+     * Clears all the manga selections and notifies the UI.
+     */
+    fun clearSelections() {
+        selectedMangas.clear()
+        selectionSubject.onNext(LibrarySelectionEvent.Cleared())
+    }
+
     /**
      * Returns the common categories for the given list of manga.
      *

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

@@ -0,0 +1,10 @@
+package eu.kanade.tachiyomi.ui.library
+
+import eu.kanade.tachiyomi.data.database.models.Manga
+
+sealed class LibrarySelectionEvent {
+
+    class Selected(val manga: Manga) : LibrarySelectionEvent()
+    class Unselected(val manga: Manga) : LibrarySelectionEvent()
+    class Cleared() : LibrarySelectionEvent()
+}

app/src/main/java/eu/kanade/tachiyomi/widget/RecyclerViewPagerAdapter.kt

@@ -0,0 +1,42 @@
+package eu.kanade.tachiyomi.widget
+
+import android.support.v4.view.PagerAdapter
+import android.view.View
+import android.view.ViewGroup
+import java.util.*
+
+abstract class RecyclerViewPagerAdapter : PagerAdapter() {
+
+    private val pool = Stack<View>()
+
+    var recycle = true
+        set(value) {
+            if (!value) pool.clear()
+            field = value
+        }
+
+    protected abstract fun createView(container: ViewGroup): View
+
+    protected abstract fun bindView(view: View, position: Int)
+
+    protected open fun recycleView(view: View, position: Int) {}
+
+    override fun instantiateItem(container: ViewGroup, position: Int): Any {
+        val view = if (pool.isNotEmpty()) pool.pop() else createView(container)
+        bindView(view, position)
+        container.addView(view)
+        return view
+    }
+
+    override fun destroyItem(container: ViewGroup, position: Int, obj: Any) {
+        val view = obj as View
+        recycleView(view, position)
+        container.removeView(view)
+        if (recycle) pool.push(view)
+    }
+
+    override fun isViewFromObject(view: View, obj: Any): Boolean {
+        return view === obj
+    }
+
+}

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

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<eu.kanade.tachiyomi.ui.library.LibraryCategoryFragment
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <android.support.v4.widget.SwipeRefreshLayout
+        android:id="@+id/swipe_refresh"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent">
+
+    </android.support.v4.widget.SwipeRefreshLayout>
+
+</eu.kanade.tachiyomi.ui.library.LibraryCategoryFragment>