Migrate library to ViewPager2

app/build.gradle

@@ -143,6 +143,7 @@ dependencies {
     implementation 'androidx.preference:preference:1.1.1'
     implementation 'androidx.recyclerview:recyclerview:1.2.0-alpha04'
     implementation 'androidx.swiperefreshlayout:swiperefreshlayout:1.1.0'
+    implementation "androidx.viewpager2:viewpager2:1.0.0"
     implementation 'androidx.webkit:webkit:1.3.0-rc01'
 
     final lifecycle_version = '2.3.0-alpha05'
@@ -259,7 +260,7 @@ dependencies {
     implementation "io.github.reactivecircus.flowbinding:flowbinding-appcompat:$flowbinding_version"
     implementation "io.github.reactivecircus.flowbinding:flowbinding-recyclerview:$flowbinding_version"
     implementation "io.github.reactivecircus.flowbinding:flowbinding-swiperefreshlayout:$flowbinding_version"
-    implementation "io.github.reactivecircus.flowbinding:flowbinding-viewpager:$flowbinding_version"
+    implementation "io.github.reactivecircus.flowbinding:flowbinding-viewpager2:$flowbinding_version"
 
     // Licenses
     final aboutlibraries_version = '8.2.0'

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

@@ -1,18 +1,20 @@
 package eu.kanade.tachiyomi.ui.library
 
+import android.content.Context
+import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
-import eu.kanade.tachiyomi.R
+import androidx.recyclerview.widget.RecyclerView
 import eu.kanade.tachiyomi.data.database.models.Category
-import eu.kanade.tachiyomi.util.view.inflate
-import eu.kanade.tachiyomi.widget.RecyclerViewPagerAdapter
+import eu.kanade.tachiyomi.databinding.LibraryCategoryBinding
 
 /**
  * This adapter stores the categories from the library, used with a ViewPager.
- *
- * @constructor creates an instance of the adapter.
  */
-class LibraryAdapter(private val controller: LibraryController) : RecyclerViewPagerAdapter() {
+class LibraryAdapter(
+    private val context: Context,
+    private val controller: LibraryController
+) : RecyclerView.Adapter<LibraryAdapter.ViewHolder>() {
 
     /**
      * The categories to bind in the adapter.
@@ -28,45 +30,25 @@ class LibraryAdapter(private val controller: LibraryController) : RecyclerViewPa
 
     private var boundViews = arrayListOf<View>()
 
-    /**
-     * Creates a new view for this adapter.
-     *
-     * @return a new view.
-     */
-    override fun createView(container: ViewGroup): View {
-        val view = container.inflate(R.layout.library_category) as LibraryCategoryView
-        view.onCreate(controller)
-        return view
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
+        val binding = LibraryCategoryBinding.inflate(LayoutInflater.from(context), parent, false)
+        binding.root.onCreate(controller)
+        return ViewHolder(binding)
     }
 
-    /**
-     * 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 LibraryCategoryView).onBind(categories[position])
+    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
+        val view = (holder.itemView as LibraryCategoryView)
+        view.onBind(categories[position])
         boundViews.add(view)
     }
 
-    /**
-     * 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 LibraryCategoryView).onRecycle()
+    override fun onViewRecycled(holder: ViewHolder) {
+        val view = (holder.itemView as LibraryCategoryView)
+        view.onRecycle()
         boundViews.remove(view)
     }
 
-    /**
-     * Returns the number of categories.
-     *
-     * @return the number of categories or 0 if the list is null.
-     */
-    override fun getCount(): Int {
+    override fun getItemCount(): Int {
         return categories.size
     }
 
@@ -76,19 +58,10 @@ class LibraryAdapter(private val controller: LibraryController) : RecyclerViewPa
      * @param position the position of the element.
      * @return the title to display.
      */
-    override fun getPageTitle(position: Int): CharSequence {
+    fun getPageTitle(position: Int): CharSequence {
         return categories[position].name
     }
 
-    /**
-     * Returns the position of the view.
-     */
-    override fun getItemPosition(obj: Any): Int {
-        val view = obj as? LibraryCategoryView ?: return POSITION_NONE
-        val index = categories.indexOfFirst { it.id == view.category.id }
-        return if (index == -1) POSITION_NONE else index
-    }
-
     /**
      * Called when the view of this adapter is being destroyed.
      */
@@ -99,4 +72,6 @@ class LibraryAdapter(private val controller: LibraryController) : RecyclerViewPa
             }
         }
     }
+
+    class ViewHolder(binding: LibraryCategoryBinding) : RecyclerView.ViewHolder(binding.root)
 }

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

@@ -15,6 +15,7 @@ import androidx.core.graphics.drawable.DrawableCompat
 import com.bluelinelabs.conductor.ControllerChangeHandler
 import com.bluelinelabs.conductor.ControllerChangeType
 import com.google.android.material.tabs.TabLayout
+import com.google.android.material.tabs.TabLayoutMediator
 import com.jakewharton.rxrelay.BehaviorRelay
 import com.jakewharton.rxrelay.PublishRelay
 import com.tfcporciuncula.flow.Preference
@@ -45,7 +46,7 @@ import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
 import reactivecircus.flowbinding.android.view.clicks
 import reactivecircus.flowbinding.appcompat.queryTextChanges
-import reactivecircus.flowbinding.viewpager.pageSelections
+import reactivecircus.flowbinding.viewpager2.pageSelections
 import rx.Subscription
 import uy.kohesive.injekt.Injekt
 import uy.kohesive.injekt.api.get
@@ -164,7 +165,8 @@ class LibraryController(
     override fun onViewCreated(view: View) {
         super.onViewCreated(view)
 
-        adapter = LibraryAdapter(this)
+        adapter = LibraryAdapter(activity!!, this)
+        binding.libraryPager.offscreenPageLimit = 5
         binding.libraryPager.adapter = adapter
         binding.libraryPager.pageSelections()
             .onEach {
@@ -212,7 +214,11 @@ class LibraryController(
     override fun onChangeStarted(handler: ControllerChangeHandler, type: ControllerChangeType) {
         super.onChangeStarted(handler, type)
         if (type.isEnter) {
-            activity?.tabs?.setupWithViewPager(binding.libraryPager)
+            activity?.tabs?.let { tabLayout ->
+                TabLayoutMediator(tabLayout, binding.libraryPager) { tab, position ->
+                    tab.text = adapter?.getPageTitle(position)
+                }.attach()
+            }
             presenter.subscribeLibrary()
         }
     }
@@ -333,10 +339,8 @@ class LibraryController(
 
         val position = binding.libraryPager.currentItem
 
-        adapter.recycle = false
         binding.libraryPager.adapter = adapter
         binding.libraryPager.currentItem = position
-        adapter.recycle = true
     }
 
     /**

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

@@ -1,34 +0,0 @@
-package eu.kanade.tachiyomi.widget
-
-import android.view.View
-import android.view.ViewGroup
-import com.nightlynexus.viewstatepageradapter.ViewStatePagerAdapter
-import java.util.Stack
-
-abstract class RecyclerViewPagerAdapter : ViewStatePagerAdapter() {
-
-    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 createView(container: ViewGroup, position: Int): View {
-        val view = if (pool.isNotEmpty()) pool.pop() else createView(container)
-        bindView(view, position)
-        return view
-    }
-
-    override fun destroyView(container: ViewGroup, position: Int, view: View) {
-        recycleView(view, position)
-        if (recycle) pool.push(view)
-    }
-}

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

@@ -39,7 +39,7 @@
             tools:text="Search"
             tools:visibility="visible" />
 
-        <androidx.viewpager.widget.ViewPager
+        <androidx.viewpager2.widget.ViewPager2
             android:id="@+id/library_pager"
             android:layout_width="match_parent"
             android:layout_height="match_parent" />