diff --git a/app/build.gradle b/app/build.gradle
index b2a372d97..46101a548 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -173,8 +173,8 @@ dependencies {
 
     //网络
     implementation 'com.squareup.okhttp3:okhttp:4.9.0'
-    implementation 'com.ljx.rxhttp:rxhttp:2.4.4-beta4'
-    kapt 'com.ljx.rxhttp:rxhttp-compiler:2.4.4-beta4'
+    implementation 'com.ljx.rxhttp:rxhttp:2.5.1'
+    kapt 'com.ljx.rxhttp:rxhttp-compiler:2.5.1'
 
     //Glide
     implementation 'com.github.bumptech.glide:glide:4.11.0'
diff --git a/app/src/main/assets/updateLog.md b/app/src/main/assets/updateLog.md
index 79223d416..ce115a174 100644
--- a/app/src/main/assets/updateLog.md
+++ b/app/src/main/assets/updateLog.md
@@ -3,6 +3,10 @@
 * 关注合作公众号 **[小说拾遗]** 获取好看的小说。
 * 旧版数据导入教程：先在旧版阅读(2.x)中进行备份，然后在新版阅读(3.x)【我的】->【备份与恢复】，选择【导入旧版本数据】。
 
+**2020/12/15**
+* 修复一些引起崩溃的bug
+* 修复搜书和换源可能什么分组都没有的bug
+
 **2020/12/14**
 * 修复bug
 * 电池图标不允许改字体
diff --git a/app/src/main/java/io/legado/app/base/adapter/CommonRecyclerAdapter.kt b/app/src/main/java/io/legado/app/base/adapter/CommonRecyclerAdapter.kt
index 0939dc242..96de8207e 100644
--- a/app/src/main/java/io/legado/app/base/adapter/CommonRecyclerAdapter.kt
+++ b/app/src/main/java/io/legado/app/base/adapter/CommonRecyclerAdapter.kt
@@ -4,11 +4,13 @@ import android.content.Context
 import android.util.SparseArray
 import android.view.LayoutInflater
 import android.view.ViewGroup
+import androidx.recyclerview.widget.AsyncListDiffer
 import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.GridLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import androidx.viewbinding.ViewBinding
 import java.util.*
+import kotlin.collections.ArrayList
 
 /**
  * Created by Invincible on 2017/11/24.
@@ -36,7 +38,10 @@ abstract class CommonRecyclerAdapter<ITEM, VB : ViewBinding>(protected val conte
     private val footerItems: SparseArray<(parent: ViewGroup) -> ViewBinding> by lazy { SparseArray() }
 
     private val itemDelegates: HashMap<Int, ItemViewDelegate<ITEM, VB>> = hashMapOf()
-    private val items: MutableList<ITEM> = mutableListOf()
+
+    private val asyncListDiffer: AsyncListDiffer<ITEM> by lazy {
+        AsyncListDiffer(this, diffItemCallback)
+    }
 
     private val lock = Object()
 
@@ -45,6 +50,19 @@ abstract class CommonRecyclerAdapter<ITEM, VB : ViewBinding>(protected val conte
 
     var itemAnimation: ItemAnimation? = null
 
+    open val diffItemCallback: DiffUtil.ItemCallback<ITEM> =
+        object : DiffUtil.ItemCallback<ITEM>() {
+
+            override fun areItemsTheSame(oldItem: ITEM, newItem: ITEM): Boolean {
+                return oldItem == newItem
+            }
+
+            override fun areContentsTheSame(oldItem: ITEM, newItem: ITEM): Boolean {
+                return true
+            }
+
+        }
+
     fun setOnItemClickListener(listener: (holder: ItemViewHolder, item: ITEM) -> Unit) {
         itemClickListener = listener
     }
@@ -115,88 +133,65 @@ abstract class CommonRecyclerAdapter<ITEM, VB : ViewBinding>(protected val conte
 
     fun setItems(items: List<ITEM>?) {
         synchronized(lock) {
-            if (this.items.isNotEmpty()) {
-                this.items.clear()
-            }
-            if (items != null) {
-                this.items.addAll(items)
-            }
-            notifyDataSetChanged()
-        }
-    }
-
-    fun setItems(items: List<ITEM>?, diffResult: DiffUtil.DiffResult) {
-        synchronized(lock) {
-            if (this.items.isNotEmpty()) {
-                this.items.clear()
-            }
-            if (items != null) {
-                this.items.addAll(items)
-            }
-            diffResult.dispatchUpdatesTo(this)
+            asyncListDiffer.submitList(items)
         }
     }
 
     fun setItem(position: Int, item: ITEM) {
         synchronized(lock) {
-            val oldSize = getActualItemCount()
-            if (position in 0 until oldSize) {
-                this.items[position] = item
-                notifyItemChanged(position + getHeaderCount())
-            }
+            val list = ArrayList(asyncListDiffer.currentList)
+            list[position] = item
+            asyncListDiffer.submitList(list)
         }
     }
 
     fun addItem(item: ITEM) {
         synchronized(lock) {
-            val oldSize = getActualItemCount()
-            if (this.items.add(item)) {
-                notifyItemInserted(oldSize + getHeaderCount())
-            }
+            val list = ArrayList(asyncListDiffer.currentList)
+            list.add(item)
+            asyncListDiffer.submitList(list)
         }
     }
 
     fun addItems(position: Int, newItems: List<ITEM>) {
         synchronized(lock) {
-            if (this.items.addAll(position, newItems)) {
-                notifyItemRangeInserted(position + getHeaderCount(), newItems.size)
-            }
+            val list = ArrayList(asyncListDiffer.currentList)
+            list.addAll(position, newItems)
+            asyncListDiffer.submitList(list)
         }
     }
 
     fun addItems(newItems: List<ITEM>) {
         synchronized(lock) {
-            val oldSize = getActualItemCount()
-            if (this.items.addAll(newItems)) {
-                if (oldSize == 0 && getHeaderCount() == 0) {
-                    notifyDataSetChanged()
-                } else {
-                    notifyItemRangeInserted(oldSize + getHeaderCount(), newItems.size)
-                }
-            }
+            val list = ArrayList(asyncListDiffer.currentList)
+            list.addAll(newItems)
+            asyncListDiffer.submitList(list)
         }
     }
 
     fun removeItem(position: Int) {
         synchronized(lock) {
-            if (this.items.removeAt(position) != null) {
-                notifyItemRemoved(position + getHeaderCount())
+            val list = ArrayList(asyncListDiffer.currentList)
+            if (list.removeAt(position) != null) {
+                asyncListDiffer.submitList(list)
             }
         }
     }
 
     fun removeItem(item: ITEM) {
         synchronized(lock) {
-            if (this.items.remove(item)) {
-                notifyItemRemoved(this.items.indexOf(item) + getHeaderCount())
+            val list = ArrayList(asyncListDiffer.currentList)
+            if (list.remove(item)) {
+                asyncListDiffer.submitList(list)
             }
         }
     }
 
     fun removeItems(items: List<ITEM>) {
         synchronized(lock) {
-            if (this.items.removeAll(items)) {
-                notifyDataSetChanged()
+            val list = ArrayList(asyncListDiffer.currentList)
+            if (list.removeAll(items)) {
+                asyncListDiffer.submitList(list)
             }
         }
     }
@@ -207,7 +202,7 @@ abstract class CommonRecyclerAdapter<ITEM, VB : ViewBinding>(protected val conte
             if (oldPosition in 0 until size && newPosition in 0 until size) {
                 val srcPosition = oldPosition + getHeaderCount()
                 val targetPosition = newPosition + getHeaderCount()
-                Collections.swap(this.items, srcPosition, targetPosition)
+                Collections.swap(asyncListDiffer.currentList, srcPosition, targetPosition)
                 notifyItemChanged(srcPosition)
                 notifyItemChanged(targetPosition)
             }
@@ -216,9 +211,9 @@ abstract class CommonRecyclerAdapter<ITEM, VB : ViewBinding>(protected val conte
 
     fun updateItem(item: ITEM) =
         synchronized(lock) {
-            val index = this.items.indexOf(item)
+            val index = asyncListDiffer.currentList.indexOf(item)
             if (index >= 0) {
-                this.items[index] = item
+                asyncListDiffer.currentList[index] = item
                 notifyItemChanged(index)
             }
         }
@@ -245,18 +240,17 @@ abstract class CommonRecyclerAdapter<ITEM, VB : ViewBinding>(protected val conte
 
     fun clearItems() =
         synchronized(lock) {
-            this.items.clear()
-            notifyDataSetChanged()
+            asyncListDiffer.submitList(arrayListOf())
         }
 
-    fun isEmpty() = items.isEmpty()
+    fun isEmpty() = asyncListDiffer.currentList.isEmpty()
 
-    fun isNotEmpty() = items.isNotEmpty()
+    fun isNotEmpty() = asyncListDiffer.currentList.isNotEmpty()
 
     /**
      * 除去header和footer
      */
-    fun getActualItemCount() = items.size
+    fun getActualItemCount() = asyncListDiffer.currentList.size
 
 
     fun getHeaderCount() = headerItems.size()
@@ -264,11 +258,12 @@ abstract class CommonRecyclerAdapter<ITEM, VB : ViewBinding>(protected val conte
 
     fun getFooterCount() = footerItems.size()
 
-    fun getItem(position: Int): ITEM? = items.getOrNull(position)
+    fun getItem(position: Int): ITEM? = asyncListDiffer.currentList.getOrNull(position)
 
-    fun getItemByLayoutPosition(position: Int) = items.getOrNull(position - getHeaderCount())
+    fun getItemByLayoutPosition(position: Int) =
+        asyncListDiffer.currentList.getOrNull(position - getHeaderCount())
 
-    fun getItems(): List<ITEM> = items
+    fun getItems(): List<ITEM> = asyncListDiffer.currentList
 
     protected open fun getItemViewType(item: ITEM, position: Int) = 0
 
diff --git a/app/src/main/java/io/legado/app/ui/book/group/GroupManageDialog.kt b/app/src/main/java/io/legado/app/ui/book/group/GroupManageDialog.kt
index 7b3b53ef2..45ee0f784 100644
--- a/app/src/main/java/io/legado/app/ui/book/group/GroupManageDialog.kt
+++ b/app/src/main/java/io/legado/app/ui/book/group/GroupManageDialog.kt
@@ -32,7 +32,6 @@ import io.legado.app.utils.*
 import io.legado.app.utils.viewbindingdelegate.viewBinding
 import org.jetbrains.anko.sdk27.listeners.onClick
 import java.util.*
-import kotlin.collections.ArrayList
 
 class GroupManageDialog : BaseDialogFragment(), Toolbar.OnMenuItemClickListener {
     private lateinit var viewModel: GroupViewModel
@@ -77,9 +76,7 @@ class GroupManageDialog : BaseDialogFragment(), Toolbar.OnMenuItemClickListener
 
     private fun initData() {
         App.db.bookGroupDao.liveDataAll().observe(viewLifecycleOwner, {
-            val diffResult =
-                DiffUtil.calculateDiff(GroupDiffCallBack(ArrayList(adapter.getItems()), it))
-            adapter.setItems(it, diffResult)
+            adapter.setItems(it)
         })
     }
 
@@ -140,40 +137,29 @@ class GroupManageDialog : BaseDialogFragment(), Toolbar.OnMenuItemClickListener
         }.show()
     }
 
-    private class GroupDiffCallBack(
-        private val oldItems: List<BookGroup>,
-        private val newItems: List<BookGroup>
-    ) : DiffUtil.Callback() {
-
-        override fun getOldListSize(): Int {
-            return oldItems.size
-        }
-
-        override fun getNewListSize(): Int {
-            return newItems.size
-        }
-
-        override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
-            val oldItem = oldItems[oldItemPosition]
-            val newItem = newItems[newItemPosition]
-            return oldItem.groupId == newItem.groupId
-        }
-
-        override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
-            val oldItem = oldItems[oldItemPosition]
-            val newItem = newItems[newItemPosition]
-            return oldItem.groupName == newItem.groupName
-                    && oldItem.show == newItem.show
-        }
-
-    }
-
     private inner class GroupAdapter(context: Context) :
         SimpleRecyclerAdapter<BookGroup, ItemGroupManageBinding>(context),
         ItemTouchCallback.Callback {
 
         private var isMoved = false
 
+        override val diffItemCallback: DiffUtil.ItemCallback<BookGroup>
+            get() = object : DiffUtil.ItemCallback<BookGroup>() {
+
+                override fun areItemsTheSame(oldItem: BookGroup, newItem: BookGroup): Boolean {
+                    return oldItem.groupId == newItem.groupId
+                }
+
+                override fun areContentsTheSame(
+                    oldItem: BookGroup,
+                    newItem: BookGroup
+                ): Boolean {
+                    return oldItem.groupName == newItem.groupName
+                            && oldItem.show == newItem.show
+                }
+
+            }
+
         override fun getViewBinding(parent: ViewGroup): ItemGroupManageBinding {
             return ItemGroupManageBinding.inflate(inflater, parent, false)
         }
diff --git a/app/src/main/java/io/legado/app/ui/book/read/config/BgTextConfigDialog.kt b/app/src/main/java/io/legado/app/ui/book/read/config/BgTextConfigDialog.kt
index 4a808df44..99d9285ea 100644
--- a/app/src/main/java/io/legado/app/ui/book/read/config/BgTextConfigDialog.kt
+++ b/app/src/main/java/io/legado/app/ui/book/read/config/BgTextConfigDialog.kt
@@ -287,7 +287,7 @@ class BgTextConfigDialog : BaseDialogFragment(), FilePickerDialog.CallBack {
 
     private fun importNetConfig(url: String) {
         execute {
-            RxHttp.get(url).toByteArray().await()?.let {
+            RxHttp.get(url).toByteArray().await().let {
                 importConfig(it)
             }
         }.onError {
diff --git a/app/src/main/java/io/legado/app/ui/book/search/DiffCallBack.kt b/app/src/main/java/io/legado/app/ui/book/search/DiffCallBack.kt
index 4125489b8..7cd271c19 100644
--- a/app/src/main/java/io/legado/app/ui/book/search/DiffCallBack.kt
+++ b/app/src/main/java/io/legado/app/ui/book/search/DiffCallBack.kt
@@ -4,20 +4,9 @@ import android.os.Bundle
 import androidx.recyclerview.widget.DiffUtil
 import io.legado.app.data.entities.SearchBook
 
-class DiffCallBack(private val oldItems: List<SearchBook>, private val newItems: List<SearchBook>) :
-    DiffUtil.Callback() {
+class DiffCallBack : DiffUtil.ItemCallback<SearchBook>() {
 
-    override fun getNewListSize(): Int {
-        return newItems.size
-    }
-
-    override fun getOldListSize(): Int {
-        return oldItems.size
-    }
-
-    override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
-        val oldItem = oldItems[oldItemPosition]
-        val newItem = newItems[newItemPosition]
+    override fun areItemsTheSame(oldItem: SearchBook, newItem: SearchBook): Boolean {
         return when {
             oldItem.name != newItem.name -> false
             oldItem.author != newItem.author -> false
@@ -25,9 +14,7 @@ class DiffCallBack(private val oldItems: List<SearchBook>, private val newItems:
         }
     }
 
-    override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
-        val oldItem = oldItems[oldItemPosition]
-        val newItem = newItems[newItemPosition]
+    override fun areContentsTheSame(oldItem: SearchBook, newItem: SearchBook): Boolean {
         return when {
             oldItem.origins.size != newItem.origins.size -> false
             oldItem.coverUrl != newItem.coverUrl -> false
@@ -38,10 +25,8 @@ class DiffCallBack(private val oldItems: List<SearchBook>, private val newItems:
         }
     }
 
-    override fun getChangePayload(oldItemPosition: Int, newItemPosition: Int): Any? {
+    override fun getChangePayload(oldItem: SearchBook, newItem: SearchBook): Any? {
         val payload = Bundle()
-        val newItem = newItems[newItemPosition]
-        val oldItem = oldItems[oldItemPosition]
         if (oldItem.name != newItem.name) payload.putString("name", newItem.name)
         if (oldItem.author != newItem.author) payload.putString("author", newItem.author)
         if (oldItem.origins.size != newItem.origins.size)
diff --git a/app/src/main/java/io/legado/app/ui/book/search/SearchAdapter.kt b/app/src/main/java/io/legado/app/ui/book/search/SearchAdapter.kt
index 10cb49d8d..20636f42f 100644
--- a/app/src/main/java/io/legado/app/ui/book/search/SearchAdapter.kt
+++ b/app/src/main/java/io/legado/app/ui/book/search/SearchAdapter.kt
@@ -3,6 +3,7 @@ package io.legado.app.ui.book.search
 import android.content.Context
 import android.os.Bundle
 import android.view.ViewGroup
+import androidx.recyclerview.widget.DiffUtil
 import io.legado.app.R
 import io.legado.app.base.adapter.ItemViewHolder
 import io.legado.app.base.adapter.SimpleRecyclerAdapter
@@ -15,6 +16,9 @@ import org.jetbrains.anko.sdk27.listeners.onClick
 class SearchAdapter(context: Context, val callBack: CallBack) :
     SimpleRecyclerAdapter<SearchBook, ItemSearchBinding>(context) {
 
+    override val diffItemCallback: DiffUtil.ItemCallback<SearchBook>
+        get() = DiffCallBack()
+
     override fun getViewBinding(parent: ViewGroup): ItemSearchBinding {
         return ItemSearchBinding.inflate(inflater, parent, false)
     }
diff --git a/app/src/main/java/io/legado/app/ui/book/source/manage/BookSourceActivity.kt b/app/src/main/java/io/legado/app/ui/book/source/manage/BookSourceActivity.kt
index 026f02a4d..5621e3b68 100644
--- a/app/src/main/java/io/legado/app/ui/book/source/manage/BookSourceActivity.kt
+++ b/app/src/main/java/io/legado/app/ui/book/source/manage/BookSourceActivity.kt
@@ -11,7 +11,6 @@ import androidx.appcompat.widget.PopupMenu
 import androidx.appcompat.widget.SearchView
 import androidx.documentfile.provider.DocumentFile
 import androidx.lifecycle.LiveData
-import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.ItemTouchHelper
 import androidx.recyclerview.widget.LinearLayoutManager
 import com.google.android.material.snackbar.Snackbar
@@ -207,9 +206,7 @@ class BookSourceActivity : VMBaseActivity<ActivityBookSourceBinding, BookSourceV
                     Sort.Update -> data.sortedBy { it.lastUpdateTime }
                     else -> data.reversed()
                 }
-            val diffResult = DiffUtil
-                .calculateDiff(DiffCallBack(ArrayList(adapter.getItems()), sourceList))
-            adapter.setItems(sourceList, diffResult)
+            adapter.setItems(sourceList)
             upCountView()
         })
     }
diff --git a/app/src/main/java/io/legado/app/ui/book/source/manage/BookSourceAdapter.kt b/app/src/main/java/io/legado/app/ui/book/source/manage/BookSourceAdapter.kt
index 93fc4fdfd..739e79120 100644
--- a/app/src/main/java/io/legado/app/ui/book/source/manage/BookSourceAdapter.kt
+++ b/app/src/main/java/io/legado/app/ui/book/source/manage/BookSourceAdapter.kt
@@ -8,6 +8,7 @@ import android.view.ViewGroup
 import android.widget.ImageView
 import android.widget.PopupMenu
 import androidx.core.os.bundleOf
+import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.RecyclerView
 import io.legado.app.R
 import io.legado.app.base.adapter.ItemViewHolder
@@ -26,6 +27,9 @@ class BookSourceAdapter(context: Context, val callBack: CallBack) :
     SimpleRecyclerAdapter<BookSource, ItemBookSourceBinding>(context),
     Callback {
 
+    override val diffItemCallback: DiffUtil.ItemCallback<BookSource>
+        get() = DiffCallBack()
+
     private val selected = linkedSetOf<BookSource>()
 
     override fun getViewBinding(parent: ViewGroup): ItemBookSourceBinding {
diff --git a/app/src/main/java/io/legado/app/ui/book/source/manage/DiffCallBack.kt b/app/src/main/java/io/legado/app/ui/book/source/manage/DiffCallBack.kt
index 8810d2dd9..787e3a129 100644
--- a/app/src/main/java/io/legado/app/ui/book/source/manage/DiffCallBack.kt
+++ b/app/src/main/java/io/legado/app/ui/book/source/manage/DiffCallBack.kt
@@ -4,28 +4,13 @@ import android.os.Bundle
 import androidx.recyclerview.widget.DiffUtil
 import io.legado.app.data.entities.BookSource
 
-class DiffCallBack(
-    private val oldItems: List<BookSource>,
-    private val newItems: List<BookSource>
-) : DiffUtil.Callback() {
+class DiffCallBack : DiffUtil.ItemCallback<BookSource>() {
 
-    override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
-        val oldItem = oldItems[oldItemPosition]
-        val newItem = newItems[newItemPosition]
+    override fun areItemsTheSame(oldItem: BookSource, newItem: BookSource): Boolean {
         return oldItem.bookSourceUrl == newItem.bookSourceUrl
     }
 
-    override fun getOldListSize(): Int {
-        return oldItems.size
-    }
-
-    override fun getNewListSize(): Int {
-        return newItems.size
-    }
-
-    override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
-        val oldItem = oldItems[oldItemPosition]
-        val newItem = newItems[newItemPosition]
+    override fun areContentsTheSame(oldItem: BookSource, newItem: BookSource): Boolean {
         if (oldItem.bookSourceName != newItem.bookSourceName)
             return false
         if (oldItem.bookSourceGroup != newItem.bookSourceGroup)
@@ -40,9 +25,7 @@ class DiffCallBack(
         return true
     }
 
-    override fun getChangePayload(oldItemPosition: Int, newItemPosition: Int): Any? {
-        val oldItem = oldItems[oldItemPosition]
-        val newItem = newItems[newItemPosition]
+    override fun getChangePayload(oldItem: BookSource, newItem: BookSource): Any? {
         val payload = Bundle()
         if (oldItem.bookSourceName != newItem.bookSourceName) {
             payload.putString("name", newItem.bookSourceName)
diff --git a/app/src/main/java/io/legado/app/ui/main/bookshelf/books/BaseBooksAdapter.kt b/app/src/main/java/io/legado/app/ui/main/bookshelf/books/BaseBooksAdapter.kt
index 54f78e25d..034003538 100644
--- a/app/src/main/java/io/legado/app/ui/main/bookshelf/books/BaseBooksAdapter.kt
+++ b/app/src/main/java/io/legado/app/ui/main/bookshelf/books/BaseBooksAdapter.kt
@@ -2,6 +2,7 @@ package io.legado.app.ui.main.bookshelf.books
 
 import android.content.Context
 import androidx.core.os.bundleOf
+import androidx.recyclerview.widget.DiffUtil
 import androidx.viewbinding.ViewBinding
 import io.legado.app.base.adapter.SimpleRecyclerAdapter
 import io.legado.app.data.entities.Book
@@ -9,6 +10,9 @@ import io.legado.app.data.entities.Book
 abstract class BaseBooksAdapter<VB : ViewBinding>(context: Context) :
     SimpleRecyclerAdapter<Book, VB>(context) {
 
+    override val diffItemCallback: DiffUtil.ItemCallback<Book>
+        get() = BooksDiffCallBack()
+
     fun notification(bookUrl: String) {
         for (i in 0 until itemCount) {
             getItem(i)?.let {
diff --git a/app/src/main/java/io/legado/app/ui/main/bookshelf/books/BooksDiffCallBack.kt b/app/src/main/java/io/legado/app/ui/main/bookshelf/books/BooksDiffCallBack.kt
index 8498b77a3..5c5fcf62f 100644
--- a/app/src/main/java/io/legado/app/ui/main/bookshelf/books/BooksDiffCallBack.kt
+++ b/app/src/main/java/io/legado/app/ui/main/bookshelf/books/BooksDiffCallBack.kt
@@ -4,27 +4,14 @@ import androidx.core.os.bundleOf
 import androidx.recyclerview.widget.DiffUtil
 import io.legado.app.data.entities.Book
 
-class BooksDiffCallBack(private val oldItems: List<Book>, private val newItems: List<Book>) :
-    DiffUtil.Callback() {
+class BooksDiffCallBack() : DiffUtil.ItemCallback<Book>() {
 
-    override fun getOldListSize(): Int {
-        return oldItems.size
-    }
-
-    override fun getNewListSize(): Int {
-        return newItems.size
-    }
-
-    override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
-        val oldItem = oldItems[oldItemPosition]
-        val newItem = newItems[newItemPosition]
+    override fun areItemsTheSame(oldItem: Book, newItem: Book): Boolean {
         return oldItem.name == newItem.name
                 && oldItem.author == newItem.author
     }
 
-    override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
-        val oldItem = oldItems[oldItemPosition]
-        val newItem = newItems[newItemPosition]
+    override fun areContentsTheSame(oldItem: Book, newItem: Book): Boolean {
         return when {
             oldItem.durChapterTime != newItem.durChapterTime -> false
             oldItem.name != newItem.name -> false
@@ -38,9 +25,7 @@ class BooksDiffCallBack(private val oldItems: List<Book>, private val newItems:
         }
     }
 
-    override fun getChangePayload(oldItemPosition: Int, newItemPosition: Int): Any? {
-        val oldItem = oldItems[oldItemPosition]
-        val newItem = newItems[newItemPosition]
+    override fun getChangePayload(oldItem: Book, newItem: Book): Any? {
         val bundle = bundleOf()
         if (oldItem.name != newItem.name) {
             bundle.putString("name", newItem.name)
diff --git a/app/src/main/java/io/legado/app/ui/main/bookshelf/books/BooksFragment.kt b/app/src/main/java/io/legado/app/ui/main/bookshelf/books/BooksFragment.kt
index 5fcdec875..77de0cc75 100644
--- a/app/src/main/java/io/legado/app/ui/main/bookshelf/books/BooksFragment.kt
+++ b/app/src/main/java/io/legado/app/ui/main/bookshelf/books/BooksFragment.kt
@@ -4,7 +4,6 @@ import android.os.Bundle
 import android.view.View
 import androidx.core.view.isGone
 import androidx.lifecycle.LiveData
-import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.GridLayoutManager
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
@@ -117,9 +116,7 @@ class BooksFragment : BaseFragment(R.layout.fragment_books),
                     3 -> list.sortedBy { it.order }
                     else -> list.sortedByDescending { it.durChapterTime }
                 }
-                val diffResult = DiffUtil
-                    .calculateDiff(BooksDiffCallBack(booksAdapter.getItems(), books))
-                booksAdapter.setItems(books, diffResult)
+                booksAdapter.setItems(books)
             }
         }
     }
diff --git a/app/src/main/java/io/legado/app/ui/replace/DiffCallBack.kt b/app/src/main/java/io/legado/app/ui/replace/DiffCallBack.kt
index 0a5200116..ea58a1fa4 100644
--- a/app/src/main/java/io/legado/app/ui/replace/DiffCallBack.kt
+++ b/app/src/main/java/io/legado/app/ui/replace/DiffCallBack.kt
@@ -4,27 +4,13 @@ import android.os.Bundle
 import androidx.recyclerview.widget.DiffUtil
 import io.legado.app.data.entities.ReplaceRule
 
-class DiffCallBack(
-    private val oldItems: List<ReplaceRule>,
-    private val newItems: List<ReplaceRule>
-) : DiffUtil.Callback() {
-    override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
-        val oldItem = oldItems[oldItemPosition]
-        val newItem = newItems[newItemPosition]
-        return oldItem.id == newItem.id
-    }
+class DiffCallBack : DiffUtil.ItemCallback<ReplaceRule>() {
 
-    override fun getOldListSize(): Int {
-        return oldItems.size
-    }
-
-    override fun getNewListSize(): Int {
-        return newItems.size
+    override fun areItemsTheSame(oldItem: ReplaceRule, newItem: ReplaceRule): Boolean {
+        return oldItem.id == newItem.id
     }
 
-    override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
-        val oldItem = oldItems[oldItemPosition]
-        val newItem = newItems[newItemPosition]
+    override fun areContentsTheSame(oldItem: ReplaceRule, newItem: ReplaceRule): Boolean {
         if (oldItem.name != newItem.name) {
             return false
         }
@@ -37,9 +23,7 @@ class DiffCallBack(
         return true
     }
 
-    override fun getChangePayload(oldItemPosition: Int, newItemPosition: Int): Any? {
-        val oldItem = oldItems[oldItemPosition]
-        val newItem = newItems[newItemPosition]
+    override fun getChangePayload(oldItem: ReplaceRule, newItem: ReplaceRule): Any? {
         val payload = Bundle()
         if (oldItem.name != newItem.name) {
             payload.putString("name", newItem.name)
diff --git a/app/src/main/java/io/legado/app/ui/replace/ReplaceRuleActivity.kt b/app/src/main/java/io/legado/app/ui/replace/ReplaceRuleActivity.kt
index b527aaade..9bd05e999 100644
--- a/app/src/main/java/io/legado/app/ui/replace/ReplaceRuleActivity.kt
+++ b/app/src/main/java/io/legado/app/ui/replace/ReplaceRuleActivity.kt
@@ -11,7 +11,6 @@ import androidx.appcompat.widget.PopupMenu
 import androidx.appcompat.widget.SearchView
 import androidx.documentfile.provider.DocumentFile
 import androidx.lifecycle.LiveData
-import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.ItemTouchHelper
 import androidx.recyclerview.widget.LinearLayoutManager
 import io.legado.app.App
@@ -153,9 +152,7 @@ class ReplaceRuleActivity : VMBaseActivity<ActivityReplaceRuleBinding, ReplaceRu
             if (dataInit) {
                 setResult(Activity.RESULT_OK)
             }
-            val diffResult =
-                DiffUtil.calculateDiff(DiffCallBack(ArrayList(adapter.getItems()), it))
-            adapter.setItems(it, diffResult)
+            adapter.setItems(it)
             dataInit = true
             upCountView()
         })
diff --git a/app/src/main/java/io/legado/app/ui/rss/source/manage/DiffCallBack.kt b/app/src/main/java/io/legado/app/ui/rss/source/manage/DiffCallBack.kt
index cb539e803..2945a9b95 100644
--- a/app/src/main/java/io/legado/app/ui/rss/source/manage/DiffCallBack.kt
+++ b/app/src/main/java/io/legado/app/ui/rss/source/manage/DiffCallBack.kt
@@ -4,36 +4,19 @@ import android.os.Bundle
 import androidx.recyclerview.widget.DiffUtil
 import io.legado.app.data.entities.RssSource
 
-class DiffCallBack(
-    private val oldItems: List<RssSource>,
-    private val newItems: List<RssSource>
-) : DiffUtil.Callback() {
+class DiffCallBack : DiffUtil.ItemCallback<RssSource>() {
 
-    override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
-        val oldItem = oldItems[oldItemPosition]
-        val newItem = newItems[newItemPosition]
+    override fun areItemsTheSame(oldItem: RssSource, newItem: RssSource): Boolean {
         return oldItem.sourceUrl == newItem.sourceUrl
     }
 
-    override fun getOldListSize(): Int {
-        return oldItems.size
-    }
-
-    override fun getNewListSize(): Int {
-        return newItems.size
-    }
-
-    override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
-        val oldItem = oldItems[oldItemPosition]
-        val newItem = newItems[newItemPosition]
+    override fun areContentsTheSame(oldItem: RssSource, newItem: RssSource): Boolean {
         return oldItem.sourceName == newItem.sourceName
                 && oldItem.sourceGroup == newItem.sourceGroup
                 && oldItem.enabled == newItem.enabled
     }
 
-    override fun getChangePayload(oldItemPosition: Int, newItemPosition: Int): Any? {
-        val oldItem = oldItems[oldItemPosition]
-        val newItem = newItems[newItemPosition]
+    override fun getChangePayload(oldItem: RssSource, newItem: RssSource): Any? {
         val payload = Bundle()
         if (oldItem.sourceName != newItem.sourceName) {
             payload.putString("name", newItem.sourceName)
diff --git a/app/src/main/java/io/legado/app/ui/rss/source/manage/RssSourceActivity.kt b/app/src/main/java/io/legado/app/ui/rss/source/manage/RssSourceActivity.kt
index 01abc2e16..94cfd3eb3 100644
--- a/app/src/main/java/io/legado/app/ui/rss/source/manage/RssSourceActivity.kt
+++ b/app/src/main/java/io/legado/app/ui/rss/source/manage/RssSourceActivity.kt
@@ -11,7 +11,6 @@ import androidx.appcompat.widget.PopupMenu
 import androidx.appcompat.widget.SearchView
 import androidx.documentfile.provider.DocumentFile
 import androidx.lifecycle.LiveData
-import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.ItemTouchHelper
 import androidx.recyclerview.widget.LinearLayoutManager
 import io.legado.app.App
@@ -209,9 +208,7 @@ class RssSourceActivity : VMBaseActivity<ActivityRssSourceBinding, RssSourceView
                 App.db.rssSourceDao.liveSearch("%$key%")
             }
         sourceLiveData?.observe(this, {
-            val diffResult = DiffUtil
-                .calculateDiff(DiffCallBack(adapter.getItems(), it))
-            adapter.setItems(it, diffResult)
+            adapter.setItems(it)
             upCountView()
         })
     }
diff --git a/app/src/main/java/io/legado/app/ui/rss/source/manage/RssSourceAdapter.kt b/app/src/main/java/io/legado/app/ui/rss/source/manage/RssSourceAdapter.kt
index 1de2c8ebe..391cad892 100644
--- a/app/src/main/java/io/legado/app/ui/rss/source/manage/RssSourceAdapter.kt
+++ b/app/src/main/java/io/legado/app/ui/rss/source/manage/RssSourceAdapter.kt
@@ -6,6 +6,7 @@ import android.view.View
 import android.view.ViewGroup
 import android.widget.PopupMenu
 import androidx.core.os.bundleOf
+import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.RecyclerView
 import io.legado.app.R
 import io.legado.app.base.adapter.ItemViewHolder
@@ -22,6 +23,9 @@ class RssSourceAdapter(context: Context, val callBack: CallBack) :
     SimpleRecyclerAdapter<RssSource, ItemRssSourceBinding>(context),
     ItemTouchCallback.Callback {
 
+    override val diffItemCallback: DiffUtil.ItemCallback<RssSource>
+        get() = DiffCallBack()
+
     private val selected = linkedSetOf<RssSource>()
 
     override fun getViewBinding(parent: ViewGroup): ItemRssSourceBinding {