优化

app/src/main/java/io/legado/app/ui/main/MainViewModel.kt

@@ -3,6 +3,7 @@ package io.legado.app.ui.main
 import android.app.Application
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.viewModelScope
+import androidx.recyclerview.widget.RecyclerView.RecycledViewPool
 import io.legado.app.base.BaseViewModel
 import io.legado.app.constant.AppConst
 import io.legado.app.constant.AppLog
@@ -52,6 +53,12 @@ class MainViewModel(application: Application) : BaseViewModel(application) {
     val onUpBooksLiveData = MutableLiveData<Int>()
     private var upTocJob: Job? = null
     private var cacheBookJob: Job? = null
+    val booksListRecycledViewPool = RecycledViewPool().apply {
+        setMaxRecycledViews(0, 30)
+    }
+    val booksGridRecycledViewPool = RecycledViewPool().apply {
+        setMaxRecycledViews(0, 100)
+    }
 
     override fun onCleared() {
         super.onCleared()

app/src/main/java/io/legado/app/ui/main/bookshelf/BaseBookshelfFragment.kt

@@ -28,7 +28,15 @@ import io.legado.app.ui.file.HandleFileContract
 import io.legado.app.ui.main.MainFragmentInterface
 import io.legado.app.ui.main.MainViewModel
 import io.legado.app.ui.widget.dialog.WaitDialog
-import io.legado.app.utils.*
+import io.legado.app.utils.checkByIndex
+import io.legado.app.utils.getCheckedIndex
+import io.legado.app.utils.isAbsUrl
+import io.legado.app.utils.postEvent
+import io.legado.app.utils.readText
+import io.legado.app.utils.sendToClip
+import io.legado.app.utils.showDialogFragment
+import io.legado.app.utils.startActivity
+import io.legado.app.utils.toastOnUi
 
 abstract class BaseBookshelfFragment(layoutId: Int) : VMBaseFragment<BookshelfViewModel>(layoutId),
     MainFragmentInterface {
@@ -198,6 +206,11 @@ abstract class BaseBookshelfFragment(layoutId: Int) : VMBaseFragment<BookshelfVi
                     }
                     if (bookshelfLayout != rgLayout.getCheckedIndex()) {
                         AppConfig.bookshelfLayout = rgLayout.getCheckedIndex()
+                        if (AppConfig.bookshelfLayout == 0) {
+                            activityViewModel.booksGridRecycledViewPool.clear()
+                        } else {
+                            activityViewModel.booksListRecycledViewPool.clear()
+                        }
                         postEvent(EventBus.RECREATE, "")
                     }
                 }

app/src/main/java/io/legado/app/ui/main/bookshelf/style1/books/BooksFragment.kt

@@ -3,6 +3,7 @@ package io.legado.app.ui.main.bookshelf.style1.books
 import android.annotation.SuppressLint
 import android.os.Bundle
 import android.view.View
+import android.view.ViewConfiguration
 import androidx.core.view.isGone
 import androidx.fragment.app.activityViewModels
 import androidx.lifecycle.Lifecycle
@@ -79,7 +80,6 @@ class BooksFragment() : BaseFragment(R.layout.fragment_books),
     var bookSort = 0
         private set
     private var upLastUpdateTimeJob: Job? = null
-    private var defaultScrollBarSize = 0
     private var enableRefresh = true
 
     override fun onFragmentCreated(view: View, savedInstanceState: Bundle?) {
@@ -97,7 +97,6 @@ class BooksFragment() : BaseFragment(R.layout.fragment_books),
 
     private fun initRecyclerView() {
         binding.rvBookshelf.setEdgeEffectColor(primaryColor)
-        defaultScrollBarSize = binding.rvBookshelf.scrollBarSize
         upFastScrollerBar()
         binding.refreshLayout.setColorSchemeColors(accentColor)
         binding.refreshLayout.setOnRefreshListener {
@@ -109,6 +108,11 @@ class BooksFragment() : BaseFragment(R.layout.fragment_books),
         } else {
             binding.rvBookshelf.layoutManager = GridLayoutManager(context, bookshelfLayout + 2)
         }
+        if (bookshelfLayout == 0) {
+            binding.rvBookshelf.setRecycledViewPool(activityViewModel.booksListRecycledViewPool)
+        } else {
+            binding.rvBookshelf.setRecycledViewPool(activityViewModel.booksGridRecycledViewPool)
+        }
         binding.rvBookshelf.adapter = booksAdapter
         booksAdapter.registerAdapterDataObserver(object : RecyclerView.AdapterDataObserver() {
             override fun onItemRangeInserted(positionStart: Int, itemCount: Int) {
@@ -136,7 +140,8 @@ class BooksFragment() : BaseFragment(R.layout.fragment_books),
         if (showBookshelfFastScroller) {
             binding.rvBookshelf.scrollBarSize = 0
         } else {
-            binding.rvBookshelf.scrollBarSize = defaultScrollBarSize
+            binding.rvBookshelf.scrollBarSize =
+                ViewConfiguration.get(requireContext()).scaledScrollBarSize
         }
     }
 
@@ -258,6 +263,15 @@ class BooksFragment() : BaseFragment(R.layout.fragment_books),
         }
     }
 
+    override fun onDestroyView() {
+        super.onDestroyView()
+        /**
+         * 将 RecyclerView 中的视图全部回收到 RecycledViewPool 中
+         */
+        binding.rvBookshelf.setItemViewCacheSize(0)
+        binding.rvBookshelf.adapter = null
+    }
+
     override fun open(book: Book) {
         when {
             book.isAudio ->